Currently the tracing_reset_all_online_cpus() requires the
trace_types_lock held. But only one caller of this function actually has
that lock held before calling it, and the other just takes the lock so
that it can call it. More users of this function is needed where the lock
is not held.
Add a tracing_reset_all_online_cpus_unlocked() function for the one use
case that calls it without being held, and also add a lockdep_assert to
make sure it is held when called.
Then have tracing_reset_all_online_cpus() take the lock internally, such
that callers do not need to worry about taking it.
Link: https://lkml.kernel.org/r/20221123192741.658273220@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
commit 94eedf3dde ("tracing: Fix race where eprobes can be called before
the event") fixed an issue where if an event is soft disabled, and the
trigger is being added, there's a small window where the event sees that
there's a trigger but does not see that it requires reading the event yet,
and then calls the trigger with the record == NULL.
This could be solved with adding memory barriers in the hot path, or to
make sure that all the triggers requiring a record check for NULL. The
latter was chosen.
Commit 94eedf3dde set the eprobe trigger handle to check for NULL, but
the same needs to be done with histograms.
Link: https://lore.kernel.org/linux-trace-kernel/20221118211809.701d40c0f8a757b0df3c025a@kernel.org/
Link: https://lore.kernel.org/linux-trace-kernel/20221123164323.03450c3a@gandalf.local.home
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 7491e2c442 ("tracing: Add a probe that attaches to trace events")
Reported-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The flag that tells the event to call its triggers after reading the event
is set for eprobes after the eprobe is enabled. This leads to a race where
the eprobe may be triggered at the beginning of the event where the record
information is NULL. The eprobe then dereferences the NULL record causing
a NULL kernel pointer bug.
Test for a NULL record to keep this from happening.
Link: https://lore.kernel.org/linux-trace-kernel/20221116192552.1066630-1-rafaelmendsr@gmail.com/
Link: https://lore.kernel.org/all/20221117214249.2addbe10@gandalf.local.home/
Cc: stable@vger.kernel.org
Fixes: 7491e2c442 ("tracing: Add a probe that attaches to trace events")
Reported-by: Rafael Mendonca <rafaelmendsr@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
The duration type is a 64 long value, not an int. This was
causing some long noise to report wrong values.
Change the duration to a 64 bits value.
Link: https://lkml.kernel.org/r/a93d8a8378c7973e9c609de05826533c9e977939.1668692096.git.bristot@kernel.org
Cc: stable@vger.kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Fixes: bce29ac9ce ("trace: Add osnoise tracer")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Before current_user_event_group(), it has allocated memory and save it
in @name, this should freed before return error.
Link: https://lkml.kernel.org/r/20221115014445.158419-1-xiujianfeng@huawei.com
Fixes: e5d271812e ("tracing/user_events: Move pages/locks into groups to prepare for namespaces")
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
There are a couple of missing * in comment blocks. Fix these.
Cleans up two clang warnings:
kernel/trace/trace_events_hist.c:986: warning: bad line:
kernel/trace/trace_events_hist.c:3229: warning: bad line:
Link: https://lkml.kernel.org/r/20221020133019.1547587-1-colin.i.king@gmail.com
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
-----BEGIN PGP SIGNATURE-----
iQFSBAABCAA8FiEEq68RxlopcLEwq+PEeb4+QwBBGIYFAmN6wAgeHHRvcnZhbGRz
QGxpbnV4LWZvdW5kYXRpb24ub3JnAAoJEHm+PkMAQRiG0EYH/3/RO90NbrFItraN
Lzr+d3VdbGjTu8xd1M+PRTmwh3zxLpB+Jwqr0T0A2gzL9B/D+AUPUJdrCVbv9DqS
FLJAVqoeV20dNBAHSffOOLPsgCZ+Eu+LzlNN7Iqde0e8cyZICFMNktitui84Xm/i
1NgFVgz9OZ6+aieYvUj3FrFq0p8GTIaC/oybDZrxYKcO8ZzKVMJ11swRw10wwq0g
qOOECvV3w7wlQ8upQZkzFxItKFc7EexZI6R4elXeGSJJ9Hlc092dv/zsKB9dwV+k
WcwkJrZRoezYXzgGBFxUcQtzi+ethjrPjuJuM1rYLUSIcfIW/0lkaSLgRoBu8D+I
1GfXkXs=
=gt6P
-----END PGP SIGNATURE-----
Merge tag 'v6.1-rc6' into x86/core, to resolve conflicts
Resolve conflicts between these commits in arch/x86/kernel/asm-offsets.c:
# upstream:
debc5a1ec0 ("KVM: x86: use a separate asm-offsets.c file")
# retbleed work in x86/core:
5d8213864a ("x86/retbleed: Add SKL return thunk")
... and these commits in include/linux/bpf.h:
# upstram:
18acb7fac2 ("bpf: Revert ("Fix dispatcher patchable function entry to 5 bytes nop")")
# x86/core commits:
931ab63664 ("x86/ibt: Implement FineIBT")
bea75b3389 ("x86/Kconfig: Introduce function padding")
The latter two modify BPF_DISPATCHER_ATTRIBUTES(), which was removed upstream.
Conflicts:
arch/x86/kernel/asm-offsets.c
include/linux/bpf.h
Signed-off-by: Ingo Molnar <mingo@kernel.org>
- Fix possible NULL pointer dereference on trace_event_file in kprobe_event_gen_test_exit()
- Fix NULL pointer dereference for trace_array in kprobe_event_gen_test_exit()
- Fix memory leak of filter string for eprobes
- Fix a possible memory leak in rethook_alloc()
- Skip clearing aggrprobe's post_handler in kprobe-on-ftrace case
which can cause a possible use-after-free
- Fix warning in eprobe filter creation
- Fix eprobe filter creation as it picked the wrong event for the fields
-----BEGIN PGP SIGNATURE-----
iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCY3qRDhQccm9zdGVkdEBn
b29kbWlzLm9yZwAKCRAp5XQQmuv6qgCdAP0cB1ZjmMM7O8OFdnrTV0jfavZTnNNC
ut9sczpYQ0upcwEArmVvB+H3sTM6Y7PrsQEUn8gsc7WmieUoDAOr0hIe4AI=
=DGVC
-----END PGP SIGNATURE-----
Merge tag 'trace-probes-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing/probes fixes from Steven Rostedt:
- Fix possible NULL pointer dereference on trace_event_file in
kprobe_event_gen_test_exit()
- Fix NULL pointer dereference for trace_array in
kprobe_event_gen_test_exit()
- Fix memory leak of filter string for eprobes
- Fix a possible memory leak in rethook_alloc()
- Skip clearing aggrprobe's post_handler in kprobe-on-ftrace case which
can cause a possible use-after-free
- Fix warning in eprobe filter creation
- Fix eprobe filter creation as it picked the wrong event for the
fields
* tag 'trace-probes-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing/eprobe: Fix eprobe filter to make a filter correctly
tracing/eprobe: Fix warning in filter creation
kprobes: Skip clearing aggrprobe's post_handler in kprobe-on-ftrace case
rethook: fix a potential memleak in rethook_alloc()
tracing/eprobe: Fix memory leak of filter string
tracing: kprobe: Fix potential null-ptr-deref on trace_array in kprobe_event_gen_test_exit()
tracing: kprobe: Fix potential null-ptr-deref on trace_event_file in kprobe_event_gen_test_exit()
The flag that tells the event to call its triggers after reading the event
is set for eprobes after the eprobe is enabled. This leads to a race where
the eprobe may be triggered at the beginning of the event where the record
information is NULL. The eprobe then dereferences the NULL record causing
a NULL kernel pointer bug.
Test for a NULL record to keep this from happening.
Link: https://lore.kernel.org/linux-trace-kernel/20221116192552.1066630-1-rafaelmendsr@gmail.com/
Link: https://lore.kernel.org/linux-trace-kernel/20221117214249.2addbe10@gandalf.local.home
Cc: Linux Trace Kernel <linux-trace-kernel@vger.kernel.org>
Cc: Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 7491e2c442 ("tracing: Add a probe that attaches to trace events")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reported-by: Rafael Mendonca <rafaelmendsr@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Kfuncs currently support specifying the KF_TRUSTED_ARGS flag to signal
to the verifier that it should enforce that a BPF program passes it a
"safe", trusted pointer. Currently, "safe" means that the pointer is
either PTR_TO_CTX, or is refcounted. There may be cases, however, where
the kernel passes a BPF program a safe / trusted pointer to an object
that the BPF program wishes to use as a kptr, but because the object
does not yet have a ref_obj_id from the perspective of the verifier, the
program would be unable to pass it to a KF_ACQUIRE | KF_TRUSTED_ARGS
kfunc.
The solution is to expand the set of pointers that are considered
trusted according to KF_TRUSTED_ARGS, so that programs can invoke kfuncs
with these pointers without getting rejected by the verifier.
There is already a PTR_UNTRUSTED flag that is set in some scenarios,
such as when a BPF program reads a kptr directly from a map
without performing a bpf_kptr_xchg() call. These pointers of course can
and should be rejected by the verifier. Unfortunately, however,
PTR_UNTRUSTED does not cover all the cases for safety that need to
be addressed to adequately protect kfuncs. Specifically, pointers
obtained by a BPF program "walking" a struct are _not_ considered
PTR_UNTRUSTED according to BPF. For example, say that we were to add a
kfunc called bpf_task_acquire(), with KF_ACQUIRE | KF_TRUSTED_ARGS, to
acquire a struct task_struct *. If we only used PTR_UNTRUSTED to signal
that a task was unsafe to pass to a kfunc, the verifier would mistakenly
allow the following unsafe BPF program to be loaded:
SEC("tp_btf/task_newtask")
int BPF_PROG(unsafe_acquire_task,
struct task_struct *task,
u64 clone_flags)
{
struct task_struct *acquired, *nested;
nested = task->last_wakee;
/* Would not be rejected by the verifier. */
acquired = bpf_task_acquire(nested);
if (!acquired)
return 0;
bpf_task_release(acquired);
return 0;
}
To address this, this patch defines a new type flag called PTR_TRUSTED
which tracks whether a PTR_TO_BTF_ID pointer is safe to pass to a
KF_TRUSTED_ARGS kfunc or a BPF helper function. PTR_TRUSTED pointers are
passed directly from the kernel as a tracepoint or struct_ops callback
argument. Any nested pointer that is obtained from walking a PTR_TRUSTED
pointer is no longer PTR_TRUSTED. From the example above, the struct
task_struct *task argument is PTR_TRUSTED, but the 'nested' pointer
obtained from 'task->last_wakee' is not PTR_TRUSTED.
A subsequent patch will add kfuncs for storing a task kfunc as a kptr,
and then another patch will add selftests to validate.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20221120051004.3605026-3-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In subsequent patches we'll arrange for architectures to have an
ftrace_regs which is entirely distinct from pt_regs. In preparation for
this, we need to minimize the use of pt_regs to where strictly necessary
in the core ftrace code.
This patch adds new ftrace_regs_{get,set}_*() helpers which can be used
to manipulate ftrace_regs. When CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS=y,
these can always be used on any ftrace_regs, and when
CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS=n these can be used when regs are
available. A new ftrace_regs_has_args(fregs) helper is added which code
can use to check when these are usable.
Co-developed-by: Florent Revest <revest@chromium.org>
Signed-off-by: Florent Revest <revest@chromium.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20221103170520.931305-4-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
In subsequent patches we'll arrange for architectures to have an
ftrace_regs which is entirely distinct from pt_regs. In preparation for
this, we need to minimize the use of pt_regs to where strictly
necessary in the core ftrace code.
This patch changes the prototype of arch_ftrace_set_direct_caller() to
take ftrace_regs rather than pt_regs, and moves the extraction of the
pt_regs into arch_ftrace_set_direct_caller().
On x86, arch_ftrace_set_direct_caller() can be used even when
CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS=n, and <linux/ftrace.h> defines
struct ftrace_regs. Due to this, it's necessary to define
arch_ftrace_set_direct_caller() as a macro to avoid using an incomplete
type. I've also moved the body of arch_ftrace_set_direct_caller() after
the CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS=y defineidion of struct
ftrace_regs.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20221103170520.931305-2-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Some architectures (powerpc) may not support ftrace locations being nop'ed
out at build time. Introduce CONFIG_HAVE_OBJTOOL_NOP_MCOUNT for objtool, as
a means for architectures to enable nop'ing of ftrace locations. Add --mnop
as an option to objtool --mcount, to indicate support for the same.
Also, make sure that --mnop can be passed as an option to objtool only when
--mcount is passed.
Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221114175754.1131267-12-sv@linux.ibm.com
Entries in list 'tr->err_log' will be reused after entry number
exceed TRACING_LOG_ERRS_MAX.
The cmd string of the to be reused entry will be freed first then
allocated a new one. If the allocation failed, then the entry will
still be in list 'tr->err_log' but its 'cmd' field is set to be NULL,
later access of 'cmd' is risky.
Currently above problem can cause the loss of 'cmd' information of first
entry in 'tr->err_log'. When execute `cat /sys/kernel/tracing/error_log`,
reproduce logs like:
[ 37.495100] trace_kprobe: error: Maxactive is not for kprobe(null) ^
[ 38.412517] trace_kprobe: error: Maxactive is not for kprobe
Command: p4:myprobe2 do_sys_openat2
^
Link: https://lore.kernel.org/linux-trace-kernel/20221114104632.3547266-1-zhengyejian1@huawei.com
Fixes: 1581a884b7 ("tracing: Remove size restriction on tracing_log_err cmd strings")
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Since the eprobe filter was defined based on the eprobe's trace event
itself, it doesn't work correctly. Use the original trace event of
the eprobe when making the filter so that the filter works correctly.
Without this fix:
# echo 'e syscalls/sys_enter_openat \
flags_rename=$flags:u32 if flags < 1000' >> dynamic_events
# echo 1 > events/eprobes/sys_enter_openat/enable
[ 114.551550] event trace: Could not enable event sys_enter_openat
-bash: echo: write error: Invalid argument
With this fix:
# echo 'e syscalls/sys_enter_openat \
flags_rename=$flags:u32 if flags < 1000' >> dynamic_events
# echo 1 > events/eprobes/sys_enter_openat/enable
# tail trace
cat-241 [000] ...1. 266.498449: sys_enter_openat: (syscalls.sys_enter_openat) flags_rename=0
cat-242 [000] ...1. 266.977640: sys_enter_openat: (syscalls.sys_enter_openat) flags_rename=0
Link: https://lore.kernel.org/all/166823166395.1385292.8931770640212414483.stgit@devnote3/
Fixes: 752be5c5c9 ("tracing/eprobe: Add eprobe filter support")
Reported-by: Rafael Mendonca <rafaelmendsr@gmail.com>
Tested-by: Rafael Mendonca <rafaelmendsr@gmail.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
In rethook_alloc(), the variable rh is not freed or passed out
if handler is NULL, which could lead to a memleak, fix it.
Link: https://lore.kernel.org/all/20221110104438.88099-1-yiyang13@huawei.com/
[Masami: Add "rethook:" tag to the title.]
Fixes: 54ecbe6f1e ("rethook: Add a generic return hook")
Cc: stable@vger.kernel.org
Signed-off-by: Yi Yang <yiyang13@huawei.com>
Acke-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
The @ftrace_mod is allocated by kzalloc(), so both the members {prev,next}
of @ftrace_mode->list are NULL, it's not a valid state to call list_del().
If kstrdup() for @ftrace_mod->{func|module} fails, it goes to @out_free
tag and calls free_ftrace_mod() to destroy @ftrace_mod, then list_del()
will write prev->next and next->prev, where null pointer dereference
happens.
BUG: kernel NULL pointer dereference, address: 0000000000000008
Oops: 0002 [#1] PREEMPT SMP NOPTI
Call Trace:
<TASK>
ftrace_mod_callback+0x20d/0x220
? do_filp_open+0xd9/0x140
ftrace_process_regex.isra.51+0xbf/0x130
ftrace_regex_write.isra.52.part.53+0x6e/0x90
vfs_write+0xee/0x3a0
? __audit_filter_op+0xb1/0x100
? auditd_test_task+0x38/0x50
ksys_write+0xa5/0xe0
do_syscall_64+0x3a/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Kernel panic - not syncing: Fatal exception
So call INIT_LIST_HEAD() to initialize the list member to fix this issue.
Link: https://lkml.kernel.org/r/20221116015207.30858-1-xiujianfeng@huawei.com
Cc: stable@vger.kernel.org
Fixes: 673feb9d76 ("ftrace: Add :mod: caching infrastructure to trace_array")
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
rb_head_page_deactivate() expects cpu_buffer to contain a valid list of
->pages, so verify that the list is actually present before calling it.
Found by Linux Verification Center (linuxtesting.org) with the SVACE
static analysis tool.
Link: https://lkml.kernel.org/r/20221114143129.3534443-1-d-tatianin@yandex-team.ru
Cc: stable@vger.kernel.org
Fixes: 77ae365eca ("ring-buffer: make lockless")
Signed-off-by: Daniil Tatianin <d-tatianin@yandex-team.ru>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
If we can't allocate this size, try something smaller with half of the
size. Its order should be decreased by one instead of divided by two.
Link: https://lkml.kernel.org/r/20221109094434.84046-3-wangwensheng4@huawei.com
Cc: <mhiramat@kernel.org>
Cc: <mark.rutland@arm.com>
Cc: stable@vger.kernel.org
Fixes: a790087554 ("ftrace: Allocate the mcount record pages as groups")
Signed-off-by: Wang Wensheng <wangwensheng4@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
If the number of mcount entries is an integer multiple of
ENTRIES_PER_PAGE, the page count showing on the console would be wrong.
Link: https://lkml.kernel.org/r/20221109094434.84046-2-wangwensheng4@huawei.com
Cc: <mhiramat@kernel.org>
Cc: <mark.rutland@arm.com>
Cc: stable@vger.kernel.org
Fixes: 5821e1b74f ("function tracing: fix wrong pos computing when read buffer has been fulfilled")
Signed-off-by: Wang Wensheng <wangwensheng4@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The function ring_buffer_nr_dirty_pages() was created to find out how many
pages are filled in the ring buffer. There's two running counters. One is
incremented whenever a new page is touched (pages_touched) and the other
is whenever a page is read (pages_read). The dirty count is the number
touched minus the number read. This is used to determine if a blocked task
should be woken up if the percentage of the ring buffer it is waiting for
is hit.
The problem is that it does not take into account dropped pages (when the
new writes overwrite pages that were not read). And then the dirty pages
will always be greater than the percentage.
This makes the "buffer_percent" file inaccurate, as the number of dirty
pages end up always being larger than the percentage, event when it's not
and this causes user space to be woken up more than it wants to be.
Add a new counter to keep track of lost pages, and include that in the
accounting of dirty pages so that it is actually accurate.
Link: https://lkml.kernel.org/r/20221021123013.55fb6055@gandalf.local.home
Fixes: 2c2b0a78b3 ("ring-buffer: Add percentage of ring buffer full to wake up reader")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Currently the way polling works on the ring buffer is broken. It will
return immediately if there's any data in the ring buffer whereas a read
will block until the watermark (defined by the tracefs buffer_percent file)
is hit.
That is, a select() or poll() will return as if there's data available,
but then the following read will block. This is broken for the way
select()s and poll()s are supposed to work.
Have the polling on the ring buffer also block the same way reads and
splice does on the ring buffer.
Link: https://lkml.kernel.org/r/20221020231427.41be3f26@gandalf.local.home
Cc: Linux Trace Kernel <linux-trace-kernel@vger.kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Primiano Tucci <primiano@google.com>
Cc: stable@vger.kernel.org
Fixes: 1e0d6714ac ("ring-buffer: Do not wake up a splice waiter when page is not full")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Since commit ab51e15d53 ("fprobe: Introduce FPROBE_FL_KPROBE_SHARED flag
for fprobe") introduced fprobe_kprobe_handler() for fprobe::ops::func,
unregister_fprobe() fails to unregister the registered if user specifies
FPROBE_FL_KPROBE_SHARED flag.
Moreover, __register_ftrace_function() is possible to change the
ftrace_ops::func, thus we have to check fprobe::ops::saved_func instead.
To check it correctly, it should confirm the fprobe::ops::saved_func is
either fprobe_handler() or fprobe_kprobe_handler().
Link: https://lore.kernel.org/all/166677683946.1459107.15997653945538644683.stgit@devnote3/
Fixes: cad9931f64 ("fprobe: Add ftrace based probe APIs")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Check if fp->rethook succeeded to be allocated. Otherwise, if
rethook_alloc() fails, then we end up dereferencing a NULL pointer in
rethook_add_node().
Link: https://lore.kernel.org/all/20221025031209.954836-1-rafaelmendsr@gmail.com/
Fixes: 5b0ab78998 ("fprobe: Add exit_handler support")
Cc: stable@vger.kernel.org
Signed-off-by: Rafael Mendonca <rafaelmendsr@gmail.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
KASAN reported a use-after-free with ftrace ops [1]. It was found from
vmcore that perf had registered two ops with the same content
successively, both dynamic. After unregistering the second ops, a
use-after-free occurred.
In ftrace_shutdown(), when the second ops is unregistered, the
FTRACE_UPDATE_CALLS command is not set because there is another enabled
ops with the same content. Also, both ops are dynamic and the ftrace
callback function is ftrace_ops_list_func, so the
FTRACE_UPDATE_TRACE_FUNC command will not be set. Eventually the value
of 'command' will be 0 and ftrace_shutdown() will skip the rcu
synchronization.
However, ftrace may be activated. When the ops is released, another CPU
may be accessing the ops. Add the missing synchronization to fix this
problem.
[1]
BUG: KASAN: use-after-free in __ftrace_ops_list_func kernel/trace/ftrace.c:7020 [inline]
BUG: KASAN: use-after-free in ftrace_ops_list_func+0x2b0/0x31c kernel/trace/ftrace.c:7049
Read of size 8 at addr ffff56551965bbc8 by task syz-executor.2/14468
CPU: 1 PID: 14468 Comm: syz-executor.2 Not tainted 5.10.0 #7
Hardware name: linux,dummy-virt (DT)
Call trace:
dump_backtrace+0x0/0x40c arch/arm64/kernel/stacktrace.c:132
show_stack+0x30/0x40 arch/arm64/kernel/stacktrace.c:196
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1b4/0x248 lib/dump_stack.c:118
print_address_description.constprop.0+0x28/0x48c mm/kasan/report.c:387
__kasan_report mm/kasan/report.c:547 [inline]
kasan_report+0x118/0x210 mm/kasan/report.c:564
check_memory_region_inline mm/kasan/generic.c:187 [inline]
__asan_load8+0x98/0xc0 mm/kasan/generic.c:253
__ftrace_ops_list_func kernel/trace/ftrace.c:7020 [inline]
ftrace_ops_list_func+0x2b0/0x31c kernel/trace/ftrace.c:7049
ftrace_graph_call+0x0/0x4
__might_sleep+0x8/0x100 include/linux/perf_event.h:1170
__might_fault mm/memory.c:5183 [inline]
__might_fault+0x58/0x70 mm/memory.c:5171
do_strncpy_from_user lib/strncpy_from_user.c:41 [inline]
strncpy_from_user+0x1f4/0x4b0 lib/strncpy_from_user.c:139
getname_flags+0xb0/0x31c fs/namei.c:149
getname+0x2c/0x40 fs/namei.c:209
[...]
Allocated by task 14445:
kasan_save_stack+0x24/0x50 mm/kasan/common.c:48
kasan_set_track mm/kasan/common.c:56 [inline]
__kasan_kmalloc mm/kasan/common.c:479 [inline]
__kasan_kmalloc.constprop.0+0x110/0x13c mm/kasan/common.c:449
kasan_kmalloc+0xc/0x14 mm/kasan/common.c:493
kmem_cache_alloc_trace+0x440/0x924 mm/slub.c:2950
kmalloc include/linux/slab.h:563 [inline]
kzalloc include/linux/slab.h:675 [inline]
perf_event_alloc.part.0+0xb4/0x1350 kernel/events/core.c:11230
perf_event_alloc kernel/events/core.c:11733 [inline]
__do_sys_perf_event_open kernel/events/core.c:11831 [inline]
__se_sys_perf_event_open+0x550/0x15f4 kernel/events/core.c:11723
__arm64_sys_perf_event_open+0x6c/0x80 kernel/events/core.c:11723
[...]
Freed by task 14445:
kasan_save_stack+0x24/0x50 mm/kasan/common.c:48
kasan_set_track+0x24/0x34 mm/kasan/common.c:56
kasan_set_free_info+0x20/0x40 mm/kasan/generic.c:358
__kasan_slab_free.part.0+0x11c/0x1b0 mm/kasan/common.c:437
__kasan_slab_free mm/kasan/common.c:445 [inline]
kasan_slab_free+0x2c/0x40 mm/kasan/common.c:446
slab_free_hook mm/slub.c:1569 [inline]
slab_free_freelist_hook mm/slub.c:1608 [inline]
slab_free mm/slub.c:3179 [inline]
kfree+0x12c/0xc10 mm/slub.c:4176
perf_event_alloc.part.0+0xa0c/0x1350 kernel/events/core.c:11434
perf_event_alloc kernel/events/core.c:11733 [inline]
__do_sys_perf_event_open kernel/events/core.c:11831 [inline]
__se_sys_perf_event_open+0x550/0x15f4 kernel/events/core.c:11723
[...]
Link: https://lore.kernel.org/linux-trace-kernel/20221103031010.166498-1-lihuafei1@huawei.com
Fixes: edb096e007 ("ftrace: Fix memleak when unregistering dynamic ops when tracing disabled")
Cc: stable@vger.kernel.org
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Li Huafei <lihuafei1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
On some machines the number of listed CPUs may be bigger than the actual
CPUs that exist. The tracing subsystem allocates a per_cpu directory with
access to the per CPU ring buffer via a cpuX file. But to save space, the
ring buffer will only allocate buffers for online CPUs, even though the
CPU array will be as big as the nr_cpu_ids.
With the addition of waking waiters on the ring buffer when closing the
file, the ring_buffer_wake_waiters() now needs to make sure that the
buffer is allocated (with the irq_work allocated with it) before trying to
wake waiters, as it will cause a NULL pointer dereference.
While debugging this, I added a NULL check for the buffer itself (which is
OK to do), and also NULL pointer checks against buffer->buffers (which is
not fine, and will WARN) as well as making sure the CPU number passed in
is within the nr_cpu_ids (which is also not fine if it isn't).
Link: https://lore.kernel.org/all/87h6zklb6n.wl-tiwai@suse.de/
Link: https://lore.kernel.org/all/CAM6Wdxc0KRJMXVAA0Y=u6Jh2V=uWB-_Fn6M4xRuNppfXzL1mUg@mail.gmail.com/
Link: https://lkml.kernel.org/linux-trace-kernel/20221101191009.1e7378c8@rorschach.local.home
Cc: stable@vger.kernel.org
Cc: Steven Noonan <steven.noonan@gmail.com>
Bugzilla: https://bugzilla.opensuse.org/show_bug.cgi?id=1204705
Reported-by: Takashi Iwai <tiwai@suse.de>
Reported-by: Roland Ruckerbauer <roland.rucky@gmail.com>
Fixes: f3ddb74ad0 ("tracing: Wake up ring buffer waiters on closing of the file")
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
-----BEGIN PGP SIGNATURE-----
iHUEABYIAB0WIQTFp0I1jqZrAX+hPRXbK58LschIgwUCY2GuKgAKCRDbK58LschI
gy32AP9PI0e/bUGDExKJ8g97PeeEtnpj4TTI6g+XKILtYnyXlgD/Rk4j2D/f3IBF
Ha9TmqYvAUim+U/g50vUrNuoNLNJ5w8=
=OKC1
-----END PGP SIGNATURE-----
Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:
====================
bpf-next 2022-11-02
We've added 70 non-merge commits during the last 14 day(s) which contain
a total of 96 files changed, 3203 insertions(+), 640 deletions(-).
The main changes are:
1) Make cgroup local storage available to non-cgroup attached BPF programs
such as tc BPF ones, from Yonghong Song.
2) Avoid unnecessary deadlock detection and failures wrt BPF task storage
helpers, from Martin KaFai Lau.
3) Add LLVM disassembler as default library for dumping JITed code
in bpftool, from Quentin Monnet.
4) Various kprobe_multi_link fixes related to kernel modules,
from Jiri Olsa.
5) Optimize x86-64 JIT with emitting BMI2-based shift instructions,
from Jie Meng.
6) Improve BPF verifier's memory type compatibility for map key/value
arguments, from Dave Marchevsky.
7) Only create mmap-able data section maps in libbpf when data is exposed
via skeletons, from Andrii Nakryiko.
8) Add an autoattach option for bpftool to load all object assets,
from Wang Yufen.
9) Various memory handling fixes for libbpf and BPF selftests,
from Xu Kuohai.
10) Initial support for BPF selftest's vmtest.sh on arm64,
from Manu Bretelle.
11) Improve libbpf's BTF handling to dedup identical structs,
from Alan Maguire.
12) Add BPF CI and denylist documentation for BPF selftests,
from Daniel Müller.
13) Check BPF cpumap max_entries before doing allocation work,
from Florian Lehner.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (70 commits)
samples/bpf: Fix typo in README
bpf: Remove the obsolte u64_stats_fetch_*_irq() users.
bpf: check max_entries before allocating memory
bpf: Fix a typo in comment for DFS algorithm
bpftool: Fix spelling mistake "disasembler" -> "disassembler"
selftests/bpf: Fix bpftool synctypes checking failure
selftests/bpf: Panic on hard/soft lockup
docs/bpf: Add documentation for new cgroup local storage
selftests/bpf: Add test cgrp_local_storage to DENYLIST.s390x
selftests/bpf: Add selftests for new cgroup local storage
selftests/bpf: Fix test test_libbpf_str/bpf_map_type_str
bpftool: Support new cgroup local storage
libbpf: Support new cgroup local storage
bpf: Implement cgroup storage available to non-cgroup-attached bpf progs
bpf: Refactor some inode/task/sk storage functions for reuse
bpf: Make struct cgroup btf id global
selftests/bpf: Tracing prog can still do lookup under busy lock
selftests/bpf: Ensure no task storage failure for bpf_lsm.s prog due to deadlock detection
bpf: Add new bpf_task_storage_delete proto with no deadlock detection
bpf: bpf_task_storage_delete_recur does lookup first before the deadlock check
...
====================
Link: https://lore.kernel.org/r/20221102062120.5724-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Similar to sk/inode/task storage, implement similar cgroup local storage.
There already exists a local storage implementation for cgroup-attached
bpf programs. See map type BPF_MAP_TYPE_CGROUP_STORAGE and helper
bpf_get_local_storage(). But there are use cases such that non-cgroup
attached bpf progs wants to access cgroup local storage data. For example,
tc egress prog has access to sk and cgroup. It is possible to use
sk local storage to emulate cgroup local storage by storing data in socket.
But this is a waste as it could be lots of sockets belonging to a particular
cgroup. Alternatively, a separate map can be created with cgroup id as the key.
But this will introduce additional overhead to manipulate the new map.
A cgroup local storage, similar to existing sk/inode/task storage,
should help for this use case.
The life-cycle of storage is managed with the life-cycle of the
cgroup struct. i.e. the storage is destroyed along with the owning cgroup
with a call to bpf_cgrp_storage_free() when cgroup itself
is deleted.
The userspace map operations can be done by using a cgroup fd as a key
passed to the lookup, update and delete operations.
Typically, the following code is used to get the current cgroup:
struct task_struct *task = bpf_get_current_task_btf();
... task->cgroups->dfl_cgrp ...
and in structure task_struct definition:
struct task_struct {
....
struct css_set __rcu *cgroups;
....
}
With sleepable program, accessing task->cgroups is not protected by rcu_read_lock.
So the current implementation only supports non-sleepable program and supporting
sleepable program will be the next step together with adding rcu_read_lock
protection for rcu tagged structures.
Since map name BPF_MAP_TYPE_CGROUP_STORAGE has been used for old cgroup local
storage support, the new map name BPF_MAP_TYPE_CGRP_STORAGE is used
for cgroup storage available to non-cgroup-attached bpf programs. The old
cgroup storage supports bpf_get_local_storage() helper to get the cgroup data.
The new cgroup storage helper bpf_cgrp_storage_get() can provide similar
functionality. While old cgroup storage pre-allocates storage memory, the new
mechanism can also pre-allocate with a user space bpf_map_update_elem() call
to avoid potential run-time memory allocation failure.
Therefore, the new cgroup storage can provide all functionality w.r.t.
the old one. So in uapi bpf.h, the old BPF_MAP_TYPE_CGROUP_STORAGE is alias to
BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED to indicate the old cgroup storage can
be deprecated since the new one can provide the same functionality.
Acked-by: David Vernet <void@manifault.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221026042850.673791-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The bpf_lsm and bpf_iter do not recur that will cause a deadlock.
The situation is similar to the bpf_pid_task_storage_delete_elem()
which is called from the syscall map_delete_elem. It does not need
deadlock detection. Otherwise, it will cause unnecessary failure
when calling the bpf_task_storage_delete() helper.
This patch adds bpf_task_storage_delete proto that does not do deadlock
detection. It will be used by bpf_lsm and bpf_iter program.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20221025184524.3526117-8-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The bpf_lsm and bpf_iter do not recur that will cause a deadlock.
The situation is similar to the bpf_pid_task_storage_lookup_elem()
which is called from the syscall map_lookup_elem. It does not need
deadlock detection. Otherwise, it will cause unnecessary failure
when calling the bpf_task_storage_get() helper.
This patch adds bpf_task_storage_get proto that does not do deadlock
detection. It will be used by bpf_lsm and bpf_iter programs.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20221025184524.3526117-6-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch adds the "_recur" naming to the bpf_task_storage_{get,delete}
proto. In a latter patch, they will only be used by the tracing
programs that requires a deadlock detection because a tracing
prog may use bpf_task_storage_{get,delete} recursively and cause a
deadlock.
Another following patch will add a different helper proto for the non
tracing programs because they do not need the deadlock prevention.
This patch does this rename to prepare for this future proto
additions.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20221025184524.3526117-3-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently we allow to create kprobe multi link on function from kernel
module, but we don't take the module reference to ensure it's not
unloaded while we are tracing it.
The multi kprobe link is based on fprobe/ftrace layer which takes
different approach and releases ftrace hooks when module is unloaded
even if there's tracer registered on top of it.
Adding code that gathers all the related modules for the link and takes
their references before it's attached. All kernel module references are
released after link is unregistered.
Note that we do it the same way already for trampoline probes
(but for single address).
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20221025134148.3300700-5-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Renaming __bpf_kprobe_multi_cookie_cmp to bpf_kprobe_multi_addrs_cmp,
because it's more suitable to current and upcoming code.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20221025134148.3300700-4-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently ftrace_lookup_symbols iterates only over core symbols,
adding module_kallsyms_on_each_symbol call to check on modules
symbols as well.
Also removing 'args.found == args.cnt' condition, because it's
already checked in kallsyms_callback function.
Also removing 'err < 0' check, because both *kallsyms_on_each_symbol
functions do not return error.
Reported-by: Martynas Pumputis <m@lambda.lt>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20221025134148.3300700-3-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
- Rework how SIGTRAPs get delivered to events to address a bunch of
problems with it. Add a selftest for that too
-----BEGIN PGP SIGNATURE-----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=DXG7
-----END PGP SIGNATURE-----
Merge tag 'perf_urgent_for_v6.1_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Borislav Petkov:
- Fix raw data handling when perf events are used in bpf
- Rework how SIGTRAPs get delivered to events to address a bunch of
problems with it. Add a selftest for that too
* tag 'perf_urgent_for_v6.1_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
bpf: Fix sample_flags for bpf_perf_event_output
selftests/perf_events: Add a SIGTRAP stress test with disables
perf: Fix missing SIGTRAPs
As previous commit, 'blk_trace_cleanup' will stop block trace if
block trace's state is 'Blktrace_running'.
So remove unnessary stop block trace in 'blk_trace_shutdown'.
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221019033602.752383-4-yebin@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When test as follows:
step1: ioctl(sda, BLKTRACESETUP, &arg)
step2: ioctl(sda, BLKTRACESTART, NULL)
step3: ioctl(sda, BLKTRACETEARDOWN, NULL)
step4: ioctl(sda, BLKTRACESETUP, &arg)
Got issue as follows:
debugfs: File 'dropped' in directory 'sda' already present!
debugfs: File 'msg' in directory 'sda' already present!
debugfs: File 'trace0' in directory 'sda' already present!
And also find syzkaller report issue like "KASAN: use-after-free Read in relay_switch_subbuf"
"https://syzkaller.appspot.com/bug?id=13849f0d9b1b818b087341691be6cc3ac6a6bfb7"
If remove block trace without stop(BLKTRACESTOP) block trace, '__blk_trace_remove'
will just set 'q->blk_trace' with NULL. However, debugfs file isn't removed, so
will report file already present when call BLKTRACESETUP.
static int __blk_trace_remove(struct request_queue *q)
{
struct blk_trace *bt;
bt = rcu_replace_pointer(q->blk_trace, NULL,
lockdep_is_held(&q->debugfs_mutex));
if (!bt)
return -EINVAL;
if (bt->trace_state != Blktrace_running)
blk_trace_cleanup(q, bt);
return 0;
}
If do test as follows:
step1: ioctl(sda, BLKTRACESETUP, &arg)
step2: ioctl(sda, BLKTRACESTART, NULL)
step3: ioctl(sda, BLKTRACETEARDOWN, NULL)
step4: remove sda
There will remove debugfs directory which will remove recursively all file
under directory.
>> blk_release_queue
>> debugfs_remove_recursive(q->debugfs_dir)
So all files which created in 'do_blk_trace_setup' are removed, and
'dentry->d_inode' is NULL. But 'q->blk_trace' is still in 'running_trace_lock',
'trace_note_tsk' will traverse 'running_trace_lock' all nodes.
>>trace_note_tsk
>> trace_note
>> relay_reserve
>> relay_switch_subbuf
>> d_inode(buf->dentry)->i_size
To solve above issues, reference commit '5afedf670caf', call 'blk_trace_cleanup'
unconditionally in '__blk_trace_remove' and first stop block trace in
'blk_trace_cleanup'.
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221019033602.752383-3-yebin@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Since ftrace has trampolines, don't use thunks for the __fentry__ site
but instead require that every function called from there includes
accounting. This very much includes all the direct-call functions.
Additionally, ftrace uses ROP tricks in two places:
- return_to_handler(), and
- ftrace_regs_caller() when pt_regs->orig_ax is set by a direct-call.
return_to_handler() already uses a retpoline to replace an
indirect-jump to defeat IBT, since this is a jump-type retpoline, make
sure there is no accounting done and ALTERNATIVE the RET into a ret.
ftrace_regs_caller() does much the same and gets the same treatment.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111148.927545073@infradead.org
* Raw data is also filled by bpf_perf_event_output.
* Add sample_flags to indicate raw data.
* This eliminates the segfaults as shown below:
Run ./samples/bpf/trace_output
BUG pid 9 cookie 1001000000004 sized 4
BUG pid 9 cookie 1001000000004 sized 4
BUG pid 9 cookie 1001000000004 sized 4
Segmentation fault (core dumped)
Fixes: 838d9bb62d ("perf: Use sample_flags for raw_data")
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/r/20221007081327.1047552-1-sumanthk@linux.ibm.com
- Found that the synthetic events were using strlen/strscpy() on values
that could have come from userspace, and that is bad.
Consolidate the string logic of kprobe and eprobe and extend it to
the synthetic events to safely process string addresses.
- Clean up content of text dump in ftrace_bug() where the output does not
make char reads into signed and sign extending the byte output.
- Fix some kernel docs in the ring buffer code.
-----BEGIN PGP SIGNATURE-----
iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCY0c6GBQccm9zdGVkdEBn
b29kbWlzLm9yZwAKCRAp5XQQmuv6qpDNAQCuw9YTeNMU4zxFqBg4/JCbfpnWQGj4
Qdl2u3WtEvTzrgEA85Q01swCYRKdrGPCrFemZ3lm6PGzpGruh+BfD4qRMwk=
=F5kK
-----END PGP SIGNATURE-----
Merge tag 'trace-v6.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:
- Found that the synthetic events were using strlen/strscpy() on values
that could have come from userspace, and that is bad.
Consolidate the string logic of kprobe and eprobe and extend it to
the synthetic events to safely process string addresses.
- Clean up content of text dump in ftrace_bug() where the output does
not make char reads into signed and sign extending the byte output.
- Fix some kernel docs in the ring buffer code.
* tag 'trace-v6.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Fix reading strings from synthetic events
tracing: Add "(fault)" name injection to kernel probes
tracing: Move duplicate code of trace_kprobe/eprobe.c into header
ring-buffer: Fix kernel-doc
ftrace: Fix char print issue in print_ip_ins()
The follow commands caused a crash:
# cd /sys/kernel/tracing
# echo 's:open char file[]' > dynamic_events
# echo 'hist:keys=common_pid:file=filename:onchange($file).trace(open,$file)' > events/syscalls/sys_enter_openat/trigger'
# echo 1 > events/synthetic/open/enable
BOOM!
The problem is that the synthetic event field "char file[]" will read
the value given to it as a string without any memory checks to make sure
the address is valid. The above example will pass in the user space
address and the sythetic event code will happily call strlen() on it
and then strscpy() where either one will cause an oops when accessing
user space addresses.
Use the helper functions from trace_kprobe and trace_eprobe that can
read strings safely (and actually succeed when the address is from user
space and the memory is mapped in).
Now the above can show:
packagekitd-1721 [000] ...2. 104.597170: open: file=/usr/lib/rpm/fileattrs/cmake.attr
in:imjournal-978 [006] ...2. 104.599642: open: file=/var/lib/rsyslog/imjournal.state.tmp
packagekitd-1721 [000] ...2. 104.626308: open: file=/usr/lib/rpm/fileattrs/debuginfo.attr
Link: https://lkml.kernel.org/r/20221012104534.826549315@goodmis.org
Cc: stable@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Fixes: bd82631d7c ("tracing: Add support for dynamic strings to synthetic events")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Have the specific functions for kernel probes that read strings to inject
the "(fault)" name directly. trace_probes.c does this too (for uprobes)
but as the code to read strings are going to be used by synthetic events
(and perhaps other utilities), it simplifies the code by making sure those
other uses do not need to implement the "(fault)" name injection as well.
Link: https://lkml.kernel.org/r/20221012104534.644803645@goodmis.org
Cc: stable@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Fixes: bd82631d7c ("tracing: Add support for dynamic strings to synthetic events")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The functions:
fetch_store_strlen_user()
fetch_store_strlen()
fetch_store_string_user()
fetch_store_string()
are identical in both trace_kprobe.c and trace_eprobe.c. Move them into
a new header file trace_probe_kernel.h to share it. This code will later
be used by the synthetic events as well.
Marked for stable as a fix for a crash in synthetic events requires it.
Link: https://lkml.kernel.org/r/20221012104534.467668078@goodmis.org
Cc: stable@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Fixes: bd82631d7c ("tracing: Add support for dynamic strings to synthetic events")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
kernel/trace/ring_buffer.c:895: warning: expecting prototype for ring_buffer_nr_pages_dirty(). Prototype was for ring_buffer_nr_dirty_pages() instead.
kernel/trace/ring_buffer.c:5313: warning: expecting prototype for ring_buffer_reset_cpu(). Prototype was for ring_buffer_reset_online_cpus() instead.
kernel/trace/ring_buffer.c:5382: warning: expecting prototype for rind_buffer_empty(). Prototype was for ring_buffer_empty() instead.
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=2340
Link: https://lkml.kernel.org/r/20221009020642.12506-1-jiapeng.chong@linux.alibaba.com
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When ftrace bug happened, following log shows every hex data in
problematic ip address:
actual: ffffffe8:6b:ffffffd9:01:21
But so many 'f's seem a little confusing, and that is because format
'%x' being used to print signed chars in array 'ins'. As suggested
by Joe, change to use format "%*phC" to print array 'ins'.
After this patch, the log is like:
actual: e8:6b:d9:01:21
Link: https://lkml.kernel.org/r/20221011120352.1878494-1-zhengyejian1@huawei.com
Fixes: 6c14133d2d ("ftrace: Do not blindly read the ip address in ftrace_bug()")
Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Major changes:
- Changed location of tracing repo from personal git repo to:
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
- Added Masami Hiramatsu as co-maintainer
- Updated MAINTAINERS file to separate out FTRACE as it is
more than just TRACING.
Minor changes:
- Added Mark Rutland as FTRACE reviewer
- Updated user_events to make it on its way to remove the BROKEN tag.
The changes should now be acceptable but will run it through
a cycle and hopefully we can remove the BROKEN tag next release.
- Added filtering to eprobes
- Added a delta time to the benchmark trace event
- Have the histogram and filter callbacks called via a switch
statement instead of indirect functions. This speeds it up to
avoid retpolines.
- Add a way to wake up ring buffer waiters waiting for the
ring buffer to fill up to its watermark.
- New ioctl() on the trace_pipe_raw file to wake up ring buffer
waiters.
- Wake up waiters when the ring buffer is disabled.
A reader may block when the ring buffer is disabled,
but if it was blocked when the ring buffer is disabled
it should then wake up.
Fixes:
- Allow splice to read partially read ring buffer pages
Fixes splice never moving forward.
- Fix inverted compare that made the "shortest" ring buffer
wait queue actually the longest.
- Fix a race in the ring buffer between resetting a page when
a writer goes to another page, and the reader.
- Fix ftrace accounting bug when function hooks are added at
boot up before the weak functions are set to "disabled".
- Fix bug that freed a user allocated snapshot buffer when
enabling a tracer.
- Fix possible recursive locks in osnoise tracer
- Fix recursive locking direct functions
- And other minor clean ups and fixes
-----BEGIN PGP SIGNATURE-----
iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCYz70cxQccm9zdGVkdEBn
b29kbWlzLm9yZwAKCRAp5XQQmuv6qpLKAP4+yOje7ZY/b3R4tTx0EIWiKdhqPx6t
Nvam2+WR2PN3QQEAqiK2A+oIbh3Zjp1MyhQWuulssWKtSTXhIQkbs7ioYAc=
=MsQw
-----END PGP SIGNATURE-----
Merge tag 'trace-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing updates from Steven Rostedt:
"Major changes:
- Changed location of tracing repo from personal git repo to:
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
- Added Masami Hiramatsu as co-maintainer
- Updated MAINTAINERS file to separate out FTRACE as it is more than
just TRACING.
Minor changes:
- Added Mark Rutland as FTRACE reviewer
- Updated user_events to make it on its way to remove the BROKEN tag.
The changes should now be acceptable but will run it through a
cycle and hopefully we can remove the BROKEN tag next release.
- Added filtering to eprobes
- Added a delta time to the benchmark trace event
- Have the histogram and filter callbacks called via a switch
statement instead of indirect functions. This speeds it up to avoid
retpolines.
- Add a way to wake up ring buffer waiters waiting for the ring
buffer to fill up to its watermark.
- New ioctl() on the trace_pipe_raw file to wake up ring buffer
waiters.
- Wake up waiters when the ring buffer is disabled. A reader may
block when the ring buffer is disabled, but if it was blocked when
the ring buffer is disabled it should then wake up.
Fixes:
- Allow splice to read partially read ring buffer pages. This fixes
splice never moving forward.
- Fix inverted compare that made the "shortest" ring buffer wait
queue actually the longest.
- Fix a race in the ring buffer between resetting a page when a
writer goes to another page, and the reader.
- Fix ftrace accounting bug when function hooks are added at boot up
before the weak functions are set to "disabled".
- Fix bug that freed a user allocated snapshot buffer when enabling a
tracer.
- Fix possible recursive locks in osnoise tracer
- Fix recursive locking direct functions
- Other minor clean ups and fixes"
* tag 'trace-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (44 commits)
ftrace: Create separate entry in MAINTAINERS for function hooks
tracing: Update MAINTAINERS to reflect new tracing git repo
tracing: Do not free snapshot if tracer is on cmdline
ftrace: Still disable enabled records marked as disabled
tracing/user_events: Move pages/locks into groups to prepare for namespaces
tracing: Add Masami Hiramatsu as co-maintainer
tracing: Remove unused variable 'dups'
MAINTAINERS: add myself as a tracing reviewer
ring-buffer: Fix race between reset page and reading page
tracing/user_events: Update ABI documentation to align to bits vs bytes
tracing/user_events: Use bits vs bytes for enabled status page data
tracing/user_events: Use refcount instead of atomic for ref tracking
tracing/user_events: Ensure user provided strings are safely formatted
tracing/user_events: Use WRITE instead of READ for io vector import
tracing/user_events: Use NULL for strstr checks
tracing: Fix spelling mistake "preapre" -> "prepare"
tracing: Wake up waiters when tracing is disabled
tracing: Add ioctl() to force ring buffer waiters to wake up
tracing: Wake up ring buffer waiters on closing of the file
ring-buffer: Add ring_buffer_wake_waiters()
...
- PMU driver updates:
- Add AMD Last Branch Record Extension Version 2 (LbrExtV2)
feature support for Zen 4 processors.
- Extend the perf ABI to provide branch speculation information,
if available, and use this on CPUs that have it (eg. LbrExtV2).
- Improve Intel PEBS TSC timestamp handling & integration.
- Add Intel Raptor Lake S CPU support.
- Add 'perf mem' and 'perf c2c' memory profiling support on
AMD CPUs by utilizing IBS tagged load/store samples.
- Clean up & optimize various x86 PMU details.
- HW breakpoints:
- Big rework to optimize the code for systems with hundreds of CPUs and
thousands of breakpoints:
- Replace the nr_bp_mutex global mutex with the bp_cpuinfo_sem
per-CPU rwsem that is read-locked during most of the key operations.
- Improve the O(#cpus * #tasks) logic in toggle_bp_slot()
and fetch_bp_busy_slots().
- Apply micro-optimizations & cleanups.
- Misc cleanups & enhancements.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
-----BEGIN PGP SIGNATURE-----
iQJFBAABCgAvFiEEBpT5eoXrXCwVQwEKEnMQ0APhK1gFAmM/2pMRHG1pbmdvQGtl
cm5lbC5vcmcACgkQEnMQ0APhK1iIMA/+J+MCEVTt9kwZeBtHoPX7iZ5gnq1+McoQ
f6ALX19AO/ZSuA7EBA3cS3Ny5eyGy3ofYUnRW+POezu9CpflLW/5N27R2qkZFrWC
A09B86WH676ZrmXt+oI05rpZ2y/NGw4gJxLLa4/bWF3g9xLfo21i+YGKwdOnNFpl
DEdCVHtjlMcOAU3+on6fOYuhXDcYd7PKGcCfLE7muOMOAtwyj0bUDBt7m+hneZgy
qbZHzDU2DZ5L/LXiMyuZj5rC7V4xUbfZZfXglG38YCW1WTieS3IjefaU2tREhu7I
rRkCK48ULDNNJR3dZK8IzXJRxusq1ICPG68I+nm/K37oZyTZWtfYZWehW/d/TnPa
tUiTwimabz7UUqaGq9ZptxwINcAigax0nl6dZ3EseeGhkDE6j71/3kqrkKPz4jth
+fCwHLOrI3c4Gq5qWgPvqcUlUneKf3DlOMtzPKYg7sMhla2zQmFpYCPzKfm77U/Z
BclGOH3FiwaK6MIjPJRUXTePXqnUseqCR8PCH/UPQUeBEVHFcMvqCaa15nALed8x
dFi76VywR9mahouuLNq6sUNePlvDd2B124PygNwegLlBfY9QmKONg9qRKOnQpuJ6
UprRJjLOOucZ/N/jn6+ShHkqmXsnY2MhfUoHUoMQ0QAI+n++e+2AuePo251kKWr8
QlqKxd9PMQU=
=LcGg
-----END PGP SIGNATURE-----
Merge tag 'perf-core-2022-10-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf events updates from Ingo Molnar:
"PMU driver updates:
- Add AMD Last Branch Record Extension Version 2 (LbrExtV2) feature
support for Zen 4 processors.
- Extend the perf ABI to provide branch speculation information, if
available, and use this on CPUs that have it (eg. LbrExtV2).
- Improve Intel PEBS TSC timestamp handling & integration.
- Add Intel Raptor Lake S CPU support.
- Add 'perf mem' and 'perf c2c' memory profiling support on AMD CPUs
by utilizing IBS tagged load/store samples.
- Clean up & optimize various x86 PMU details.
HW breakpoints:
- Big rework to optimize the code for systems with hundreds of CPUs
and thousands of breakpoints:
- Replace the nr_bp_mutex global mutex with the bp_cpuinfo_sem
per-CPU rwsem that is read-locked during most of the key
operations.
- Improve the O(#cpus * #tasks) logic in toggle_bp_slot() and
fetch_bp_busy_slots().
- Apply micro-optimizations & cleanups.
- Misc cleanups & enhancements"
* tag 'perf-core-2022-10-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (75 commits)
perf/hw_breakpoint: Annotate tsk->perf_event_mutex vs ctx->mutex
perf: Fix pmu_filter_match()
perf: Fix lockdep_assert_event_ctx()
perf/x86/amd/lbr: Adjust LBR regardless of filtering
perf/x86/utils: Fix uninitialized var in get_branch_type()
perf/uapi: Define PERF_MEM_SNOOPX_PEER in kernel header file
perf/x86/amd: Support PERF_SAMPLE_PHY_ADDR
perf/x86/amd: Support PERF_SAMPLE_ADDR
perf/x86/amd: Support PERF_SAMPLE_{WEIGHT|WEIGHT_STRUCT}
perf/x86/amd: Support PERF_SAMPLE_DATA_SRC
perf/x86/amd: Add IBS OP_DATA2 DataSrc bit definitions
perf/mem: Introduce PERF_MEM_LVLNUM_{EXTN_MEM|IO}
perf/x86/uncore: Add new Raptor Lake S support
perf/x86/cstate: Add new Raptor Lake S support
perf/x86/msr: Add new Raptor Lake S support
perf/x86: Add new Raptor Lake S support
bpf: Check flags for branch stack in bpf_read_branch_records helper
perf, hw_breakpoint: Fix use-after-free if perf_event_open() fails
perf: Use sample_flags for raw_data
perf: Use sample_flags for addr
...
The ftrace_boot_snapshot and alloc_snapshot cmdline options allocate the
snapshot buffer at boot up for use later. The ftrace_boot_snapshot in
particular requires the snapshot to be allocated because it will take a
snapshot at the end of boot up allowing to see the traces that happened
during boot so that it's not lost when user space takes over.
When a tracer is registered (started) there's a path that checks if it
requires the snapshot buffer or not, and if it does not and it was
allocated it will do a synchronization and free the snapshot buffer.
This is only required if the previous tracer was using it for "max
latency" snapshots, as it needs to make sure all max snapshots are
complete before freeing. But this is only needed if the previous tracer
was using the snapshot buffer for latency (like irqoff tracer and
friends). But it does not make sense to free it, if the previous tracer
was not using it, and the snapshot was allocated by the cmdline
parameters. This basically takes away the point of allocating it in the
first place!
Note, the allocated snapshot worked fine for just trace events, but fails
when a tracer is enabled on the cmdline.
Further investigation, this goes back even further and it does not require
a tracer on the cmdline to fail. Simply enable snapshots and then enable a
tracer, and it will remove the snapshot.
Link: https://lkml.kernel.org/r/20221005113757.041df7fe@gandalf.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Fixes: 45ad21ca55 ("tracing: Have trace_array keep track if snapshot buffer is allocated")
Reported-by: Ross Zwisler <zwisler@kernel.org>
Tested-by: Ross Zwisler <zwisler@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Weak functions started causing havoc as they showed up in the
"available_filter_functions" and this confused people as to why some
functions marked as "notrace" were listed, but when enabled they did
nothing. This was because weak functions can still have fentry calls, and
these addresses get added to the "available_filter_functions" file.
kallsyms is what converts those addresses to names, and since the weak
functions are not listed in kallsyms, it would just pick the function
before that.
To solve this, there was a trick to detect weak functions listed, and
these records would be marked as DISABLED so that they do not get enabled
and are mostly ignored. As the processing of the list of all functions to
figure out what is weak or not can take a long time, this process is put
off into a kernel thread and run in parallel with the rest of start up.
Now the issue happens whet function tracing is enabled via the kernel
command line. As it starts very early in boot up, it can be enabled before
the records that are weak are marked to be disabled. This causes an issue
in the accounting, as the weak records are enabled by the command line
function tracing, but after boot up, they are not disabled.
The ftrace records have several accounting flags and a ref count. The
DISABLED flag is just one. If the record is enabled before it is marked
DISABLED it will get an ENABLED flag and also have its ref counter
incremented. After it is marked for DISABLED, neither the ENABLED flag nor
the ref counter is cleared. There's sanity checks on the records that are
performed after an ftrace function is registered or unregistered, and this
detected that there were records marked as ENABLED with ref counter that
should not have been.
Note, the module loading code uses the DISABLED flag as well to keep its
functions from being modified while its being loaded and some of these
flags may get set in this process. So changing the verification code to
ignore DISABLED records is a no go, as it still needs to verify that the
module records are working too.
Also, the weak functions still are calling a trampoline. Even though they
should never be called, it is dangerous to leave these weak functions
calling a trampoline that is freed, so they should still be set back to
nops.
There's two places that need to not skip records that have the ENABLED
and the DISABLED flags set. That is where the ftrace_ops is processed and
sets the records ref counts, and then later when the function itself is to
be updated, and the ENABLED flag gets removed. Add a helper function
"skip_record()" that returns true if the record has the DISABLED flag set
but not the ENABLED flag.
Link: https://lkml.kernel.org/r/20221005003809.27d2b97b@gandalf.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Fixes: b39181f7c6 ("ftrace: Add FTRACE_MCOUNT_MAX_OFFSET to avoid adding weak function")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Daniel Borkmann says:
====================
pull-request: bpf-next 2022-10-03
We've added 143 non-merge commits during the last 27 day(s) which contain
a total of 151 files changed, 8321 insertions(+), 1402 deletions(-).
The main changes are:
1) Add kfuncs for PKCS#7 signature verification from BPF programs, from Roberto Sassu.
2) Add support for struct-based arguments for trampoline based BPF programs,
from Yonghong Song.
3) Fix entry IP for kprobe-multi and trampoline probes under IBT enabled, from Jiri Olsa.
4) Batch of improvements to veristat selftest tool in particular to add CSV output,
a comparison mode for CSV outputs and filtering, from Andrii Nakryiko.
5) Add preparatory changes needed for the BPF core for upcoming BPF HID support,
from Benjamin Tissoires.
6) Support for direct writes to nf_conn's mark field from tc and XDP BPF program
types, from Daniel Xu.
7) Initial batch of documentation improvements for BPF insn set spec, from Dave Thaler.
8) Add a new BPF_MAP_TYPE_USER_RINGBUF map which provides single-user-space-producer /
single-kernel-consumer semantics for BPF ring buffer, from David Vernet.
9) Follow-up fixes to BPF allocator under RT to always use raw spinlock for the BPF
hashtab's bucket lock, from Hou Tao.
10) Allow creating an iterator that loops through only the resources of one
task/thread instead of all, from Kui-Feng Lee.
11) Add support for kptrs in the per-CPU arraymap, from Kumar Kartikeya Dwivedi.
12) Add a new kfunc helper for nf to set src/dst NAT IP/port in a newly allocated CT
entry which is not yet inserted, from Lorenzo Bianconi.
13) Remove invalid recursion check for struct_ops for TCP congestion control BPF
programs, from Martin KaFai Lau.
14) Fix W^X issue with BPF trampoline and BPF dispatcher, from Song Liu.
15) Fix percpu_counter leakage in BPF hashtab allocation error path, from Tetsuo Handa.
16) Various cleanups in BPF selftests to use preferred ASSERT_* macros, from Wang Yufen.
17) Add invocation for cgroup/connect{4,6} BPF programs for ICMP pings, from YiFei Zhu.
18) Lift blinding decision under bpf_jit_harden = 1 to bpf_capable(), from Yauheni Kaliuta.
19) Various libbpf fixes and cleanups including a libbpf NULL pointer deref, from Xin Liu.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (143 commits)
net: netfilter: move bpf_ct_set_nat_info kfunc in nf_nat_bpf.c
Documentation: bpf: Add implementation notes documentations to table of contents
bpf, docs: Delete misformatted table.
selftests/xsk: Fix double free
bpftool: Fix error message of strerror
libbpf: Fix overrun in netlink attribute iteration
selftests/bpf: Fix spelling mistake "unpriviledged" -> "unprivileged"
samples/bpf: Fix typo in xdp_router_ipv4 sample
bpftool: Remove unused struct event_ring_info
bpftool: Remove unused struct btf_attach_point
bpf, docs: Add TOC and fix formatting.
bpf, docs: Add Clang note about BPF_ALU
bpf, docs: Move Clang notes to a separate file
bpf, docs: Linux byteswap note
bpf, docs: Move legacy packet instructions to a separate file
selftests/bpf: Check -EBUSY for the recurred bpf_setsockopt(TCP_CONGESTION)
bpf: tcp: Stop bpf_setsockopt(TCP_CONGESTION) in init ops to recur itself
bpf: Refactor bpf_setsockopt(TCP_CONGESTION) handling into another function
bpf: Move the "cdg" tcp-cc check to the common sol_tcp_sockopt()
bpf: Add __bpf_prog_{enter,exit}_struct_ops for struct_ops trampoline
...
====================
Link: https://lore.kernel.org/r/20221003194915.11847-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In order to enable namespaces or any sort of isolation within
user_events the register lock and pages need to be broken up into
groups. Each event and file now has a group pointer which stores the
actual pages to map, lookup data and synchronization objects.
This only enables a single group that maps to init_user_ns, as IMA
namespace has done. This enables user_events to start the work of
supporting namespaces by walking the namespaces up to the init_user_ns.
Future patches will address other user namespaces and will align to the
approaches the IMA namespace uses.
Link: https://lore.kernel.org/linux-kernel/20220915193221.1728029-15-stefanb@linux.ibm.com/#t
Link: https://lkml.kernel.org/r/20221001001016.2832-2-beaub@linux.microsoft.com
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Reported by Clang [-Wunused-but-set-variable]
'commit c193707dde ("tracing: Remove code which merges duplicates")'
This commit removed the code which merges duplicates in detect_dups(),
but forgot to delete the variable 'dups' which used to merge
duplicates in the loop.
Now only 'total_dups' is needed, remove 'dups' for clean code.
Link: https://lkml.kernel.org/r/20220930103236.253985-1-chenzhongjin@huawei.com
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The ring buffer is broken up into sub buffers (currently of page size).
Each sub buffer has a pointer to its "tail" (the last event written to the
sub buffer). When a new event is requested, the tail is locally
incremented to cover the size of the new event. This is done in a way that
there is no need for locking.
If the tail goes past the end of the sub buffer, the process of moving to
the next sub buffer takes place. After setting the current sub buffer to
the next one, the previous one that had the tail go passed the end of the
sub buffer needs to be reset back to the original tail location (before
the new event was requested) and the rest of the sub buffer needs to be
"padded".
The race happens when a reader takes control of the sub buffer. As readers
do a "swap" of sub buffers from the ring buffer to get exclusive access to
the sub buffer, it replaces the "head" sub buffer with an empty sub buffer
that goes back into the writable portion of the ring buffer. This swap can
happen as soon as the writer moves to the next sub buffer and before it
updates the last sub buffer with padding.
Because the sub buffer can be released to the reader while the writer is
still updating the padding, it is possible for the reader to see the event
that goes past the end of the sub buffer. This can cause obvious issues.
To fix this, add a few memory barriers so that the reader definitely sees
the updates to the sub buffer, and also waits until the writer has put
back the "tail" of the sub buffer back to the last event that was written
on it.
To be paranoid, it will only spin for 1 second, otherwise it will
warn and shutdown the ring buffer code. 1 second should be enough as
the writer does have preemption disabled. If the writer doesn't move
within 1 second (with preemption disabled) something is horribly
wrong. No interrupt should last 1 second!
Link: https://lore.kernel.org/all/20220830120854.7545-1-jiazi.li@transsion.com/
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216369
Link: https://lkml.kernel.org/r/20220929104909.0650a36c@gandalf.local.home
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Fixes: c7b0930857 ("ring-buffer: prevent adding write in discarded area")
Reported-by: Jiazi.Li <jiazi.li@transsion.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
User processes may require many events and when they do the cache
performance of a byte index status check is less ideal than a bit index.
The previous event limit per-page was 4096, the new limit is 32,768.
This change adds a bitwise index to the user_reg struct. Programs check
that the bit at status_bit has a bit set within the status page(s).
Link: https://lkml.kernel.org/r/20220728233309.1896-6-beaub@linux.microsoft.com
Link: https://lore.kernel.org/all/2059213643.196683.1648499088753.JavaMail.zimbra@efficios.com/
Suggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
User processes could open up enough event references to cause rollovers.
These could cause use after free scenarios, which we do not want.
Switching to refcount APIs prevent this, but will leak memory once
saturated.
Once saturated, user processes can still use the events. This prevents
a bad user process from stopping existing telemetry from being emitted.
Link: https://lkml.kernel.org/r/20220728233309.1896-5-beaub@linux.microsoft.com
Link: https://lore.kernel.org/all/2059213643.196683.1648499088753.JavaMail.zimbra@efficios.com/
Reported-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When tracing is disabled, there's no reason that waiters should stay
waiting, wake them up, otherwise tasks get stuck when they should be
flushing the buffers.
Cc: stable@vger.kernel.org
Fixes: e30f53aad2 ("tracing: Do not busy wait in buffer splice")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
If a process is waiting on the ring buffer for data, there currently isn't
a clean way to force it to wake up. Add an ioctl call that will force any
tasks that are waiting on the trace_pipe_raw file to wake up.
Link: https://lkml.kernel.org/r/20220929095029.117f913f@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: e30f53aad2 ("tracing: Do not busy wait in buffer splice")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When the file that represents the ring buffer is closed, there may be
waiters waiting on more input from the ring buffer. Call
ring_buffer_wake_waiters() to wake up any waiters when the file is
closed.
Link: https://lkml.kernel.org/r/20220927231825.182416969@goodmis.org
Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: e30f53aad2 ("tracing: Do not busy wait in buffer splice")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
On closing of a file that represents a ring buffer or flushing the file,
there may be waiters on the ring buffer that needs to be woken up and exit
the ring_buffer_wait() function.
Add ring_buffer_wake_waiters() to wake up the waiters on the ring buffer
and allow them to exit the wait loop.
Link: https://lkml.kernel.org/r/20220928133938.28dc2c27@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 15693458c4 ("tracing/ring-buffer: Move poll wake ups into ring buffer code")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The wake up waiters only checks the "wakeup_full" variable and not the
"full_waiters_pending". The full_waiters_pending is set when a waiter is
added to the wait queue. The wakeup_full is only set when an event is
triggered, and it clears the full_waiters_pending to avoid multiple calls
to irq_work_queue().
The irq_work callback really needs to check both wakeup_full as well as
full_waiters_pending such that this code can be used to wake up waiters
when a file is closed that represents the ring buffer and the waiters need
to be woken up.
Link: https://lkml.kernel.org/r/20220927231824.209460321@goodmis.org
Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 15693458c4 ("tracing/ring-buffer: Move poll wake ups into ring buffer code")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The logic to know when the shortest waiters on the ring buffer should be
woken up or not has uses a less than instead of a greater than compare,
which causes the shortest_full to actually be the longest.
Link: https://lkml.kernel.org/r/20220927231823.718039222@goodmis.org
Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 2c2b0a78b3 ("ring-buffer: Add percentage of ring buffer full to wake up reader")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Recent commit [1] changed branch stack data indication from
br_stack pointer to sample_flags in perf_sample_data struct.
We need to check sample_flags for PERF_SAMPLE_BRANCH_STACK
bit for valid branch stack data.
[1] a9a931e266 ("perf: Use sample_flags for branch stack")
Fixes: a9a931e266 ("perf: Use sample_flags for branch stack")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Link: https://lore.kernel.org/r/20220927203259.590950-1-jolsa@kernel.org
If a page is partially read, and then the splice system call is run
against the ring buffer, it will always fail to read, no matter how much
is in the ring buffer. That's because the code path for a partial read of
the page does will fail if the "full" flag is set.
The splice system call wants full pages, so if the read of the ring buffer
is not yet full, it should return zero, and the splice will block. But if
a previous read was done, where the beginning has been consumed, it should
still be given to the splice caller if the rest of the page has been
written to.
This caused the splice command to never consume data in this scenario, and
let the ring buffer just fill up and lose events.
Link: https://lkml.kernel.org/r/20220927144317.46be6b80@gandalf.local.home
Cc: stable@vger.kernel.org
Fixes: 8789a9e7df ("ring-buffer: read page interface")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When executing following commands like what document said, but the log
"#### all functions enabled ####" was not shown as expect:
1. Set a 'mod' filter:
$ echo 'write*:mod:ext3' > /sys/kernel/tracing/set_ftrace_filter
2. Invert above filter:
$ echo '!write*:mod:ext3' >> /sys/kernel/tracing/set_ftrace_filter
3. Read the file:
$ cat /sys/kernel/tracing/set_ftrace_filter
By some debugging, I found that flag FTRACE_HASH_FL_MOD was not unset
after inversion like above step 2 and then result of ftrace_hash_empty()
is incorrect.
Link: https://lkml.kernel.org/r/20220926152008.2239274-1-zhengyejian1@huawei.com
Cc: <mingo@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 8c08f0d5c6 ("ftrace: Have cached module filters be an active filter")
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The event dir will alloc failed when event name no set, using the
command:
"echo "e:esys/ syscalls/sys_enter_openat file=\$filename:string"
>> dynamic_events"
It seems that dir name="syscalls/sys_enter_openat" is not allowed
in debugfs. So just use the "sys_enter_openat" as the event name.
Link: https://lkml.kernel.org/r/1664028814-45923-1-git-send-email-chentao.kernel@linux.alibaba.com
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Linyu Yuan <quic_linyyuan@quicinc.com>
Cc: Tao Chen <chentao.kernel@linux.alibaba.com
Cc: stable@vger.kernel.org
Fixes: 95c104c378 ("tracing: Auto generate event name when creating a group of events")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Tao Chen <chentao.kernel@linux.alibaba.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
It was found that some tracing functions in kernel/trace/trace.c acquire
an arch_spinlock_t with preemption and irqs enabled. An example is the
tracing_saved_cmdlines_size_read() function which intermittently causes
a "BUG: using smp_processor_id() in preemptible" warning when the LTP
read_all_proc test is run.
That can be problematic in case preemption happens after acquiring the
lock. Add the necessary preemption or interrupt disabling code in the
appropriate places before acquiring an arch_spinlock_t.
The convention here is to disable preemption for trace_cmdline_lock and
interupt for max_lock.
Link: https://lkml.kernel.org/r/20220922145622.1744826-1-longman@redhat.com
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: stable@vger.kernel.org
Fixes: a35873a099 ("tracing: Add conditional snapshot")
Fixes: 939c7a4f04 ("tracing: Introduce saved_cmdlines_size file")
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Changing return value of kprobe's version of bpf_get_func_ip
to return zero if the attach address is not on the function's
entry point.
For kprobes attached in the middle of the function we can't easily
get to the function address especially now with the CONFIG_X86_KERNEL_IBT
support.
If user cares about current IP for kprobes attached within the
function body, they can get it with PT_REGS_IP(ctx).
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Martynas Pumputis <m@lambda.lt>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220926153340.1621984-6-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Martynas reported bpf_get_func_ip returning +4 address when
CONFIG_X86_KERNEL_IBT option is enabled.
When CONFIG_X86_KERNEL_IBT is enabled we'll have endbr instruction
at the function entry, which screws return value of bpf_get_func_ip()
helper that should return the function address.
There's short term workaround for kprobe_multi bpf program made by
Alexei [1], but we need this fixup also for bpf_get_attach_cookie,
that returns cookie based on the entry_ip value.
Moving the fixup in the fprobe handler, so both bpf_get_func_ip
and bpf_get_attach_cookie get expected function address when
CONFIG_X86_KERNEL_IBT option is enabled.
Also renaming kprobe_multi_link_handler entry_ip argument to fentry_ip
so it's clearer this is an ftrace __fentry__ ip.
[1] commit 7f0059b58f ("selftests/bpf: Fix kprobe_multi test.")
Cc: Peter Zijlstra <peterz@infradead.org>
Reported-by: Martynas Pumputis <m@lambda.lt>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220926153340.1621984-5-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Keeping the resolved 'addr' in kallsyms_callback, instead of taking
ftrace_location value, because we depend on symbol address in the
cookie related code.
With CONFIG_X86_KERNEL_IBT option the ftrace_location value differs
from symbol address, which screwes the symbol address cookies matching.
There are 2 users of this function:
- bpf_kprobe_multi_link_attach
for which this fix is for
- get_ftrace_locations
which is used by register_fprobe_syms
this function needs to get symbols resolved to addresses,
but does not need 'ftrace location addresses' at this point
there's another ftrace location translation in the path done
by ftrace_set_filter_ips call:
register_fprobe_syms
addrs = get_ftrace_locations
register_fprobe_ips(addrs)
...
ftrace_set_filter_ips
...
__ftrace_match_addr
ip = ftrace_location(ip);
...
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220926153340.1621984-3-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
There is a recursive lock on the cpu_hotplug_lock.
In kernel/trace/trace_osnoise.c:<start/stop>_per_cpu_kthreads:
- start_per_cpu_kthreads calls cpus_read_lock() and if
start_kthreads returns a error it will call stop_per_cpu_kthreads.
- stop_per_cpu_kthreads then calls cpus_read_lock() again causing
deadlock.
Fix this by calling cpus_read_unlock() before calling
stop_per_cpu_kthreads. This behavior can also be seen in commit
f46b16520a ("trace/hwlat: Implement the per-cpu mode").
This error was noticed during the LTP ftrace-stress-test:
WARNING: possible recursive locking detected
--------------------------------------------
sh/275006 is trying to acquire lock:
ffffffffb02f5400 (cpu_hotplug_lock){++++}-{0:0}, at: stop_per_cpu_kthreads
but task is already holding lock:
ffffffffb02f5400 (cpu_hotplug_lock){++++}-{0:0}, at: start_per_cpu_kthreads
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(cpu_hotplug_lock);
lock(cpu_hotplug_lock);
*** DEADLOCK ***
May be due to missing lock nesting notation
3 locks held by sh/275006:
#0: ffff8881023f0470 (sb_writers#24){.+.+}-{0:0}, at: ksys_write
#1: ffffffffb084f430 (trace_types_lock){+.+.}-{3:3}, at: rb_simple_write
#2: ffffffffb02f5400 (cpu_hotplug_lock){++++}-{0:0}, at: start_per_cpu_kthreads
Link: https://lkml.kernel.org/r/20220919144932.3064014-1-npache@redhat.com
Fixes: c8895e271f ("trace/osnoise: Support hotplug operations")
Signed-off-by: Nico Pache <npache@redhat.com>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
For now, this selftest module can only work in x86 because of the
kprobe cmd was fixed use of x86 registers.
This patch adapted to register names under arm and riscv, So that
this module can be worked on those platform.
Link: https://lkml.kernel.org/r/20220919125629.238242-3-zouyipeng@huawei.com
Cc: <linux-riscv@lists.infradead.org>
Cc: <mingo@redhat.com>
Cc: <paul.walmsley@sifive.com>
Cc: <palmer@dabbelt.com>
Cc: <aou@eecs.berkeley.edu>
Cc: <zanussi@kernel.org>
Cc: <liaochang1@huawei.com>
Cc: <chris.zjh@huawei.com>
Fixes: 64836248dd ("tracing: Add kprobe event command generation test module")
Signed-off-by: Yipeng Zou <zouyipeng@huawei.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The structure filter_pred and the typedef of the function used are only
referenced by trace_events_filter.c. There's no reason to have it in an
external header file. Move them into the only file they are used in.
Link: https://lkml.kernel.org/r/20220906225529.598047132@goodmis.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
In order to testing filtering and histograms via the trace event
benchmark, record the delta time of the last event as a numeric value
(currently, it just saves it within the string) so that filters and
histograms can use it.
Link: https://lkml.kernel.org/r/20220906225529.213677569@goodmis.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The sparse tool complains as follows:
kernel/trace/rv/monitors/wwnr/wwnr.c:18:19:
warning: symbol 'rv_wwnr' was not declared. Should it be static?
The `rv_wwnr` symbol is not dereferenced by other extern files,
so add static qualifier for it.
So does wip module.
Link: https://lkml.kernel.org/r/20220824034357.2014202-2-zengheng4@huawei.com
Cc: <mingo@redhat.com>
Fixes: ccc319dcb4 ("rv/monitor: Add the wwnr monitor")
Fixes: 8812d21219 ("rv/monitor: Add the wip monitor skeleton created by dot2k")
Signed-off-by: Zeng Heng <zengheng4@huawei.com>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Add the filter option to the event probe. This is useful if user wants
to derive a new event based on the condition of the original event.
E.g.
echo 'e:egroup/stat_runtime_4core sched/sched_stat_runtime \
runtime=$runtime:u32 if cpu < 4' >> ../dynamic_events
Then it can filter the events only on first 4 cores.
Note that the fields used for 'if' must be the fields in the original
events, not eprobe events.
Link: https://lkml.kernel.org/r/165932114513.2850673.2592206685744598080.stgit@devnote2
Cc: Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
We got report from sysbot [1] about warnings that were caused by
bpf program attached to contention_begin raw tracepoint triggering
the same tracepoint by using bpf_trace_printk helper that takes
trace_printk_lock lock.
Call Trace:
<TASK>
? trace_event_raw_event_bpf_trace_printk+0x5f/0x90
bpf_trace_printk+0x2b/0xe0
bpf_prog_a9aec6167c091eef_prog+0x1f/0x24
bpf_trace_run2+0x26/0x90
native_queued_spin_lock_slowpath+0x1c6/0x2b0
_raw_spin_lock_irqsave+0x44/0x50
bpf_trace_printk+0x3f/0xe0
bpf_prog_a9aec6167c091eef_prog+0x1f/0x24
bpf_trace_run2+0x26/0x90
native_queued_spin_lock_slowpath+0x1c6/0x2b0
_raw_spin_lock_irqsave+0x44/0x50
bpf_trace_printk+0x3f/0xe0
bpf_prog_a9aec6167c091eef_prog+0x1f/0x24
bpf_trace_run2+0x26/0x90
native_queued_spin_lock_slowpath+0x1c6/0x2b0
_raw_spin_lock_irqsave+0x44/0x50
bpf_trace_printk+0x3f/0xe0
bpf_prog_a9aec6167c091eef_prog+0x1f/0x24
bpf_trace_run2+0x26/0x90
native_queued_spin_lock_slowpath+0x1c6/0x2b0
_raw_spin_lock_irqsave+0x44/0x50
__unfreeze_partials+0x5b/0x160
...
The can be reproduced by attaching bpf program as raw tracepoint on
contention_begin tracepoint. The bpf prog calls bpf_trace_printk
helper. Then by running perf bench the spin lock code is forced to
take slow path and call contention_begin tracepoint.
Fixing this by skipping execution of the bpf program if it's
already running, Using bpf prog 'active' field, which is being
currently used by trampoline programs for the same reason.
Moving bpf_prog_inc_misses_counter to syscall.c because
trampoline.c is compiled in just for CONFIG_BPF_JIT option.
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Reported-by: syzbot+2251879aa068ad9c960d@syzkaller.appspotmail.com
[1] https://lore.kernel.org/bpf/YxhFe3EwqchC%2FfYf@krava/T/#t
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220916071914.7156-1-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add the bpf_verify_pkcs7_signature() kfunc, to give eBPF security modules
the ability to check the validity of a signature against supplied data, by
using user-provided or system-provided keys as trust anchor.
The new kfunc makes it possible to enforce mandatory policies, as eBPF
programs might be allowed to make security decisions only based on data
sources the system administrator approves.
The caller should provide the data to be verified and the signature as eBPF
dynamic pointers (to minimize the number of parameters) and a bpf_key
structure containing a reference to the keyring with keys trusted for
signature verification, obtained from bpf_lookup_user_key() or
bpf_lookup_system_key().
For bpf_key structures obtained from the former lookup function,
bpf_verify_pkcs7_signature() completes the permission check deferred by
that function by calling key_validate(). key_task_permission() is already
called by the PKCS#7 code.
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: KP Singh <kpsingh@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20220920075951.929132-9-roberto.sassu@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add the bpf_lookup_user_key(), bpf_lookup_system_key() and bpf_key_put()
kfuncs, to respectively search a key with a given key handle serial number
and flags, obtain a key from a pre-determined ID defined in
include/linux/verification.h, and cleanup.
Introduce system_keyring_id_check() to validate the keyring ID parameter of
bpf_lookup_system_key().
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20220920075951.929132-8-roberto.sassu@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Steven Rostedt (Google)