BPF_STX instruction preserves STACK_ZERO marks for variable offset
writes in situations like below:
*(u64*)(r10 - 8) = 0 ; STACK_ZERO marks for fp[-8]
r0 = random(-7, -1) ; some random number in range of [-7, -1]
r0 += r10 ; r0 is now a variable offset pointer to stack
r1 = 0
*(u8*)(r0) = r1 ; BPF_STX writing zero, STACK_ZERO mark for
; fp[-8] is preserved
This commit updates verifier.c:check_stack_write_var_off() to process
BPF_ST in a similar manner, e.g. the following example:
*(u64*)(r10 - 8) = 0 ; STACK_ZERO marks for fp[-8]
r0 = random(-7, -1) ; some random number in range of [-7, -1]
r0 += r10 ; r0 is now variable offset pointer to stack
*(u8*)(r0) = 0 ; BPF_ST writing zero, STACK_ZERO mark for
; fp[-8] is preserved
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230214232030.1502829-4-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
For aligned stack writes using BPF_ST instruction track stored values
in a same way BPF_STX is handled, e.g. make sure that the following
commands produce similar verifier knowledge:
fp[-8] = 42; r1 = 42;
fp[-8] = r1;
This covers two cases:
- non-null values written to stack are stored as spill of fake
registers;
- null values written to stack are stored as STACK_ZERO marks.
Previously both cases above used STACK_MISC marks instead.
Some verifier test cases relied on the old logic to obtain STACK_MISC
marks for some stack values. These test cases are updated in the same
commit to avoid failures during bisect.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230214232030.1502829-2-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Newly-added bpf_rbtree_{remove,first} kfuncs have some special properties
that require handling in the verifier:
* both bpf_rbtree_remove and bpf_rbtree_first return the type containing
the bpf_rb_node field, with the offset set to that field's offset,
instead of a struct bpf_rb_node *
* mark_reg_graph_node helper added in previous patch generalizes
this logic, use it
* bpf_rbtree_remove's node input is a node that's been inserted
in the tree - a non-owning reference.
* bpf_rbtree_remove must invalidate non-owning references in order to
avoid aliasing issue. Use previously-added
invalidate_non_owning_refs helper to mark this function as a
non-owning ref invalidation point.
* Unlike other functions, which convert one of their input arg regs to
non-owning reference, bpf_rbtree_first takes no arguments and just
returns a non-owning reference (possibly null)
* For now verifier logic for this is special-cased instead of
adding new kfunc flag.
This patch, along with the previous one, complete special verifier
handling for all rbtree API functions added in this series.
With functional verifier handling of rbtree_remove, under current
non-owning reference scheme, a node type with both bpf_{list,rb}_node
fields could cause the verifier to accept programs which remove such
nodes from collections they haven't been added to.
In order to prevent this, this patch adds a check to btf_parse_fields
which rejects structs with both bpf_{list,rb}_node fields. This is a
temporary measure that can be removed after "collection identity"
followup. See comment added in btf_parse_fields. A linked_list BTF test
exercising the new check is added in this patch as well.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-6-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Some BPF helpers take a callback function which the helper calls. For
each helper that takes such a callback, there's a special call to
__check_func_call with a callback-state-setting callback that sets up
verifier bpf_func_state for the callback's frame.
kfuncs don't have any of this infrastructure yet, so let's add it in
this patch, following existing helper pattern as much as possible. To
validate functionality of this added plumbing, this patch adds
callback handling for the bpf_rbtree_add kfunc and hopes to lay
groundwork for future graph datastructure callbacks.
In the "general plumbing" category we have:
* check_kfunc_call doing callback verification right before clearing
CALLER_SAVED_REGS, exactly like check_helper_call
* recognition of func_ptr BTF types in kfunc args as
KF_ARG_PTR_TO_CALLBACK + propagation of subprogno for this arg type
In the "rbtree_add / graph datastructure-specific plumbing" category:
* Since bpf_rbtree_add must be called while the spin_lock associated
with the tree is held, don't complain when callback's func_state
doesn't unlock it by frame exit
* Mark rbtree_add callback's args with ref_set_non_owning
to prevent rbtree api functions from being called in the callback.
Semantically this makes sense, as less() takes no ownership of its
args when determining which comes first.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-5-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Now that we find bpf_rb_root and bpf_rb_node in structs, let's give args
that contain those types special classification and properly handle
these types when checking kfunc args.
"Properly handling" these types largely requires generalizing similar
handling for bpf_list_{head,node}, with little new logic added in this
patch.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-4-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch adds implementations of bpf_rbtree_{add,remove,first}
and teaches verifier about their BTF_IDs as well as those of
bpf_rb_{root,node}.
All three kfuncs have some nonstandard component to their verification
that needs to be addressed in future patches before programs can
properly use them:
* bpf_rbtree_add: Takes 'less' callback, need to verify it
* bpf_rbtree_first: Returns ptr_to_node_type(off=rb_node_off) instead
of ptr_to_rb_node(off=0). Return value ref is
non-owning.
* bpf_rbtree_remove: Returns ptr_to_node_type(off=rb_node_off) instead
of ptr_to_rb_node(off=0). 2nd arg (node) is a
non-owning reference.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-3-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch adds special BPF_RB_{ROOT,NODE} btf_field_types similar to
BPF_LIST_{HEAD,NODE}, adds the necessary plumbing to detect the new
types, and adds bpf_rb_root_free function for freeing bpf_rb_root in
map_values.
structs bpf_rb_root and bpf_rb_node are opaque types meant to
obscure structs rb_root_cached rb_node, respectively.
btf_struct_access will prevent BPF programs from touching these special
fields automatically now that they're recognized.
btf_check_and_fixup_fields now groups list_head and rb_root together as
"graph root" fields and {list,rb}_node as "graph node", and does same
ownership cycle checking as before. Note that this function does _not_
prevent ownership type mixups (e.g. rb_root owning list_node) - that's
handled by btf_parse_graph_root.
After this patch, a bpf program can have a struct bpf_rb_root in a
map_value, but not add anything to nor do anything useful with it.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-2-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch introduces non-owning reference semantics to the verifier,
specifically linked_list API kfunc handling. release_on_unlock logic for
refs is refactored - with small functional changes - to implement these
semantics, and bpf_list_push_{front,back} are migrated to use them.
When a list node is pushed to a list, the program still has a pointer to
the node:
n = bpf_obj_new(typeof(*n));
bpf_spin_lock(&l);
bpf_list_push_back(&l, n);
/* n still points to the just-added node */
bpf_spin_unlock(&l);
What the verifier considers n to be after the push, and thus what can be
done with n, are changed by this patch.
Common properties both before/after this patch:
* After push, n is only a valid reference to the node until end of
critical section
* After push, n cannot be pushed to any list
* After push, the program can read the node's fields using n
Before:
* After push, n retains the ref_obj_id which it received on
bpf_obj_new, but the associated bpf_reference_state's
release_on_unlock field is set to true
* release_on_unlock field and associated logic is used to implement
"n is only a valid ref until end of critical section"
* After push, n cannot be written to, the node must be removed from
the list before writing to its fields
* After push, n is marked PTR_UNTRUSTED
After:
* After push, n's ref is released and ref_obj_id set to 0. NON_OWN_REF
type flag is added to reg's type, indicating that it's a non-owning
reference.
* NON_OWN_REF flag and logic is used to implement "n is only a
valid ref until end of critical section"
* n can be written to (except for special fields e.g. bpf_list_node,
timer, ...)
Summary of specific implementation changes to achieve the above:
* release_on_unlock field, ref_set_release_on_unlock helper, and logic
to "release on unlock" based on that field are removed
* The anonymous active_lock struct used by bpf_verifier_state is
pulled out into a named struct bpf_active_lock.
* NON_OWN_REF type flag is introduced along with verifier logic
changes to handle non-owning refs
* Helpers are added to use NON_OWN_REF flag to implement non-owning
ref semantics as described above
* invalidate_non_owning_refs - helper to clobber all non-owning refs
matching a particular bpf_active_lock identity. Replaces
release_on_unlock logic in process_spin_lock.
* ref_set_non_owning - set NON_OWN_REF type flag after doing some
sanity checking
* ref_convert_owning_non_owning - convert owning reference w/
specified ref_obj_id to non-owning references. Set NON_OWN_REF
flag for each reg with that ref_obj_id and 0-out its ref_obj_id
* Update linked_list selftests to account for minor semantic
differences introduced by this patch
* Writes to a release_on_unlock node ref are not allowed, while
writes to non-owning reference pointees are. As a result the
linked_list "write after push" failure tests are no longer scenarios
that should fail.
* The test##missing_lock##op and test##incorrect_lock##op
macro-generated failure tests need to have a valid node argument in
order to have the same error output as before. Otherwise
verification will fail early and the expected error output won't be seen.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230212092715.1422619-2-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
We can simply disable the bpf prog memory accouting by not setting the
GFP_ACCOUNT.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://lore.kernel.org/r/20230210154734.4416-5-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
We can simply set root memcg as the map's memcg to disable bpf memory
accounting. bpf_map_area_alloc is a little special as it gets the memcg
from current rather than from the map, so we need to disable GFP_ACCOUNT
specifically for it.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://lore.kernel.org/r/20230210154734.4416-4-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce new helper bpf_map_kvcalloc() for the memory allocation in
bpf_local_storage(). Then the allocation will charge the memory from the
map instead of from current, though currently they are the same thing as
it is only used in map creation path now. By charging map's memory into
the memcg from the map, it will be more clear.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://lore.kernel.org/r/20230210154734.4416-3-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Daniel Borkmann says:
====================
pull-request: bpf-next 2023-02-11
We've added 96 non-merge commits during the last 14 day(s) which contain
a total of 152 files changed, 4884 insertions(+), 962 deletions(-).
There is a minor conflict in drivers/net/ethernet/intel/ice/ice_main.c
between commit 5b246e533d ("ice: split probe into smaller functions")
from the net-next tree and commit 66c0e13ad2 ("drivers: net: turn on
XDP features") from the bpf-next tree. Remove the hunk given ice_cfg_netdev()
is otherwise there a 2nd time, and add XDP features to the existing
ice_cfg_netdev() one:
[...]
ice_set_netdev_features(netdev);
netdev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
NETDEV_XDP_ACT_XSK_ZEROCOPY;
ice_set_ops(netdev);
[...]
Stephen's merge conflict mail:
https://lore.kernel.org/bpf/20230207101951.21a114fa@canb.auug.org.au/
The main changes are:
1) Add support for BPF trampoline on s390x which finally allows to remove many
test cases from the BPF CI's DENYLIST.s390x, from Ilya Leoshkevich.
2) Add multi-buffer XDP support to ice driver, from Maciej Fijalkowski.
3) Add capability to export the XDP features supported by the NIC.
Along with that, add a XDP compliance test tool,
from Lorenzo Bianconi & Marek Majtyka.
4) Add __bpf_kfunc tag for marking kernel functions as kfuncs,
from David Vernet.
5) Add a deep dive documentation about the verifier's register
liveness tracking algorithm, from Eduard Zingerman.
6) Fix and follow-up cleanups for resolve_btfids to be compiled
as a host program to avoid cross compile issues,
from Jiri Olsa & Ian Rogers.
7) Batch of fixes to the BPF selftest for xdp_hw_metadata which resulted
when testing on different NICs, from Jesper Dangaard Brouer.
8) Fix libbpf to better detect kernel version code on Debian, from Hao Xiang.
9) Extend libbpf to add an option for when the perf buffer should
wake up, from Jon Doron.
10) Follow-up fix on xdp_metadata selftest to just consume on TX
completion, from Stanislav Fomichev.
11) Extend the kfuncs.rst document with description on kfunc
lifecycle & stability expectations, from David Vernet.
12) Fix bpftool prog profile to skip attaching to offline CPUs,
from Tonghao Zhang.
====================
Link: https://lore.kernel.org/r/20230211002037.8489-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
skbuff_head_cache is misnamed (perhaps for historical reasons?)
because it does not hold heads. Head is the buffer which skb->data
points to, and also where shinfo lives. struct sk_buff is a metadata
structure, not the head.
Eric recently added skb_small_head_cache (which allocates actual
head buffers), let that serve as an excuse to finally clean this up :)
Leave the user-space visible name intact, it could possibly be uAPI.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Tariq has pointed out that drivers allocating IRQ vectors would benefit
from having smarter NUMA-awareness - cpumask_local_spread() only knows
about the local node and everything outside is in the same bucket.
sched_domains_numa_masks is pretty much what we want to hand out (a cpumask
of CPUs reachable within a given distance budget), introduce
sched_numa_hop_mask() to export those cpumasks.
Link: http://lore.kernel.org/r/20220728191203.4055-1-tariqt@nvidia.com
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The function finds Nth set CPU in a given cpumask starting from a given
node.
Leveraging the fact that each hop in sched_domains_numa_masks includes the
same or greater number of CPUs than the previous one, we can use binary
search on hops instead of linear walk, which makes the overall complexity
of O(log n) in terms of number of cpumask_weight() calls.
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Acked-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Peter Lafreniere <peter@n8pjl.ca>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
With the fix that made poll() and select() block if read would block
caused a slight regression in rasdaemon, as it needed that kind
of behavior. Add a way to make that behavior come back by writing
zero into the "buffer_percentage", which means to never block on read.
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Merge tag 'trace-v6.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fix from Steven Rostedt:
"Fix regression in poll() and select()
With the fix that made poll() and select() block if read would block
caused a slight regression in rasdaemon, as it needed that kind of
behavior. Add a way to make that behavior come back by writing zero
into the 'buffer_percentage', which means to never block on read"
* tag 'trace-v6.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Fix poll() and select() do not work on per_cpu trace_pipe and trace_pipe_raw
set_cpus_allowed_ptr() will fail with -EINVAL if the requested
affinity mask is not a subset of the task_cpu_possible_mask() for the
task being updated. Consequently, on a heterogeneous system with cpusets
spanning the different CPU types, updates to the cgroup hierarchy can
silently fail to update task affinities when the effective affinity
mask for the cpuset is expanded.
For example, consider an arm64 system with 4 CPUs, where CPUs 2-3 are
the only cores capable of executing 32-bit tasks. Attaching a 32-bit
task to a cpuset containing CPUs 0-2 will correctly affine the task to
CPU 2. Extending the cpuset to CPUs 0-3, however, will fail to extend
the affinity mask of the 32-bit task because update_tasks_cpumask() will
pass the full 0-3 mask to set_cpus_allowed_ptr().
Extend update_tasks_cpumask() to take a temporary 'cpumask' paramater
and use it to mask the 'effective_cpus' mask with the possible mask for
each task being updated.
Fixes: 431c69fac0 ("cpuset: Honour task_cpu_possible_mask() in guarantee_online_cpus()")
Signed-off-by: Will Deacon <will@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Since commit 8f9ea86fdf ("sched: Always preserve the user
requested cpumask"), relax_compatible_cpus_allowed_ptr() is calling
__sched_setaffinity() unconditionally. This helps to expose a bug in
the current cpuset hotplug code where the cpumasks of the tasks in
the top cpuset are not updated at all when some CPUs become online or
offline. It is likely caused by the fact that some of the tasks in the
top cpuset, like percpu kthreads, cannot have their cpu affinity changed.
One way to reproduce this as suggested by Peter is:
- boot machine
- offline all CPUs except one
- taskset -p ffffffff $$
- online all CPUs
Fix this by allowing cpuset_cpus_allowed() to return a wider mask that
includes offline CPUs for those tasks that are in the top cpuset. For
tasks not in the top cpuset, the old rule applies and only online CPUs
will be returned in the mask since hotplug events will update their
cpumasks accordingly.
Fixes: 8f9ea86fdf ("sched: Always preserve the user requested cpumask")
Reported-by: Will Deacon <will@kernel.org>
Originally-from: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Will Deacon <will@kernel.org>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Here are a number of small char/misc/whatever driver fixes for 6.2-rc7.
They include:
- IIO driver fixes for some reported problems
- nvmem driver fixes
- fpga driver fixes
- debugfs memory leak fix in the hv_balloon and irqdomain code
(irqdomain change was acked by the maintainer.)
All have been in linux-next with no reported problems.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'char-misc-6.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char/misc driver fixes from Greg KH:
"Here are a number of small char/misc/whatever driver fixes. They
include:
- IIO driver fixes for some reported problems
- nvmem driver fixes
- fpga driver fixes
- debugfs memory leak fix in the hv_balloon and irqdomain code
(irqdomain change was acked by the maintainer)
All have been in linux-next with no reported problems"
* tag 'char-misc-6.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (33 commits)
kernel/irq/irqdomain.c: fix memory leak with using debugfs_lookup()
HV: hv_balloon: fix memory leak with using debugfs_lookup()
nvmem: qcom-spmi-sdam: fix module autoloading
nvmem: core: fix return value
nvmem: core: fix cell removal on error
nvmem: core: fix device node refcounting
nvmem: core: fix registration vs use race
nvmem: core: fix cleanup after dev_set_name()
nvmem: core: remove nvmem_config wp_gpio
nvmem: core: initialise nvmem->id early
nvmem: sunxi_sid: Always use 32-bit MMIO reads
nvmem: brcm_nvram: Add check for kzalloc
iio: imu: fxos8700: fix MAGN sensor scale and unit
iio: imu: fxos8700: remove definition FXOS8700_CTRL_ODR_MIN
iio: imu: fxos8700: fix failed initialization ODR mode assignment
iio: imu: fxos8700: fix incorrect ODR mode readback
iio: light: cm32181: Fix PM support on system with 2 I2C resources
iio: hid: fix the retval in gyro_3d_capture_sample
iio: hid: fix the retval in accel_3d_capture_sample
iio: imu: st_lsm6dsx: fix build when CONFIG_IIO_TRIGGERED_BUFFER=m
...
When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time. To make things simpler, just
call debugfs_lookup_and_remove() instead which handles all of the logic
at once.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable <stable@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230202151554.2310273-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The do_idr_lock parameter to bpf_map_free_id was introduced by commit
bd5f5f4ecb ("bpf: Add BPF_MAP_GET_FD_BY_ID"). However, all callers set
do_idr_lock = true since commit 1e0bd5a091 ("bpf: Switch bpf_map ref
counter to atomic64_t so bpf_map_inc() never fails").
While at it also inline __bpf_map_put into its only caller bpf_map_put
now that do_idr_lock can be dropped from its signature.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Link: https://lore.kernel.org/r/20230202141921.4424-1-tklauser@distanz.ch
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Current release - regressions:
- phy: fix null-deref in phy_attach_direct
- mac802154: fix possible double free upon parsing error
Previous releases - regressions:
- bpf: preserve reg parent/live fields when copying range info,
prevent mis-verification of programs as safe
- ip6: fix GRE tunnels not generating IPv6 link local addresses
- phy: dp83822: fix null-deref on DP83825/DP83826 devices
- sctp: do not check hb_timer.expires when resetting hb_timer
- eth: mtk_sock: fix SGMII configuration after phylink conversion
Previous releases - always broken:
- eth: xdp: execute xdp_do_flush() before napi_complete_done()
- skb: do not mix page pool and page referenced frags in GRO
- bpf:
- fix a possible task gone issue with bpf_send_signal[_thread]()
- fix an off-by-one bug in bpf_mem_cache_idx() to select
the right cache
- add missing btf_put to register_btf_id_dtor_kfuncs
- sockmap: fon't let sock_map_{close,destroy,unhash} call itself
- gso: fix null-deref in skb_segment_list()
- mctp: purge receive queues on sk destruction
- fix UaF caused by accept on already connected socket in exotic
socket families
- tls: don't treat list head as an entry in tls_is_tx_ready()
- netfilter: br_netfilter: disable sabotage_in hook after first
suppression
- wwan: t7xx: fix runtime PM implementation
Misc:
- MAINTAINERS: spring cleanup of networking maintainers
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-6.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Jakub Kicinski:
"Including fixes from bpf, can and netfilter.
Current release - regressions:
- phy: fix null-deref in phy_attach_direct
- mac802154: fix possible double free upon parsing error
Previous releases - regressions:
- bpf: preserve reg parent/live fields when copying range info,
prevent mis-verification of programs as safe
- ip6: fix GRE tunnels not generating IPv6 link local addresses
- phy: dp83822: fix null-deref on DP83825/DP83826 devices
- sctp: do not check hb_timer.expires when resetting hb_timer
- eth: mtk_sock: fix SGMII configuration after phylink conversion
Previous releases - always broken:
- eth: xdp: execute xdp_do_flush() before napi_complete_done()
- skb: do not mix page pool and page referenced frags in GRO
- bpf:
- fix a possible task gone issue with bpf_send_signal[_thread]()
- fix an off-by-one bug in bpf_mem_cache_idx() to select the right
cache
- add missing btf_put to register_btf_id_dtor_kfuncs
- sockmap: fon't let sock_map_{close,destroy,unhash} call itself
- gso: fix null-deref in skb_segment_list()
- mctp: purge receive queues on sk destruction
- fix UaF caused by accept on already connected socket in exotic
socket families
- tls: don't treat list head as an entry in tls_is_tx_ready()
- netfilter: br_netfilter: disable sabotage_in hook after first
suppression
- wwan: t7xx: fix runtime PM implementation
Misc:
- MAINTAINERS: spring cleanup of networking maintainers"
* tag 'net-6.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (65 commits)
mtk_sgmii: enable PCS polling to allow SFP work
net: mediatek: sgmii: fix duplex configuration
net: mediatek: sgmii: ensure the SGMII PHY is powered down on configuration
MAINTAINERS: update SCTP maintainers
MAINTAINERS: ipv6: retire Hideaki Yoshifuji
mailmap: add John Crispin's entry
MAINTAINERS: bonding: move Veaceslav Falico to CREDITS
net: openvswitch: fix flow memory leak in ovs_flow_cmd_new
net: ethernet: mtk_eth_soc: disable hardware DSA untagging for second MAC
virtio-net: Keep stop() to follow mirror sequence of open()
selftests: net: udpgso_bench_tx: Cater for pending datagrams zerocopy benchmarking
selftests: net: udpgso_bench: Fix racing bug between the rx/tx programs
selftests: net: udpgso_bench_rx/tx: Stop when wrong CLI args are provided
selftests: net: udpgso_bench_rx: Fix 'used uninitialized' compiler warning
can: mcp251xfd: mcp251xfd_ring_set_ringparam(): assign missing tx_obj_num_coalesce_irq
can: isotp: split tx timer into transmission and timeout
can: isotp: handle wait_event_interruptible() return values
can: raw: fix CAN FD frame transmissions over CAN XL devices
can: j1939: fix errant WARN_ON_ONCE in j1939_session_deactivate
hv_netvsc: Fix missed pagebuf entries in netvsc_dma_map/unmap()
...
poll() and select() on per_cpu trace_pipe and trace_pipe_raw do not work
since kernel 6.1-rc6. This issue is seen after the commit
42fb0a1e84 ("tracing/ring-buffer: Have
polling block on watermark").
This issue is firstly detected and reported, when testing the CXL error
events in the rasdaemon and also erified using the test application for poll()
and select().
This issue occurs for the per_cpu case, when calling the ring_buffer_poll_wait(),
in kernel/trace/ring_buffer.c, with the buffer_percent > 0 and then wait until the
percentage of pages are available. The default value set for the buffer_percent is 50
in the kernel/trace/trace.c.
As a fix, allow userspace application could set buffer_percent as 0 through
the buffer_percent_fops, so that the task will wake up as soon as data is added
to any of the specific cpu buffer.
Link: https://lore.kernel.org/linux-trace-kernel/20230202182309.742-2-shiju.jose@huawei.com
Cc: <mhiramat@kernel.org>
Cc: <mchehab@kernel.org>
Cc: <linux-edac@vger.kernel.org>
Cc: stable@vger.kernel.org
Fixes: 42fb0a1e84 ("tracing/ring-buffer: Have polling block on watermark")
Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Now that we have the __bpf_kfunc tag, we should use add it to all
existing kfuncs to ensure that they'll never be elided in LTO builds.
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230201173016.342758-4-void@manifault.com
It was found that the check to see if a partition could use up all
the cpus from the parent cpuset in update_parent_subparts_cpumask()
was incorrect. As a result, it is possible to leave parent with no
effective cpu left even if there are tasks in the parent cpuset. This
can lead to system panic as reported in [1].
Fix this probem by updating the check to fail the enabling the partition
if parent's effective_cpus is a subset of the child's cpus_allowed.
Also record the error code when an error happens in update_prstate()
and add a test case where parent partition and child have the same cpu
list and parent has task. Enabling partition in the child will fail in
this case.
[1] https://www.spinics.net/lists/cgroups/msg36254.html
Fixes: f0af1bfc27 ("cgroup/cpuset: Relax constraints to partition & cpus changes")
Cc: stable@vger.kernel.org # v6.1
Reported-by: Srinivas Pandruvada <srinivas.pandruvada@intel.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Syzkaller triggered a WARN in put_pmu_ctx().
WARNING: CPU: 1 PID: 2245 at kernel/events/core.c:4925 put_pmu_ctx+0x1f0/0x278
This is because there is no locking around the access of "if
(!epc->ctx)" in find_get_pmu_context() and when it is set to NULL in
put_pmu_ctx().
The decrement of the reference count in put_pmu_ctx() also happens
outside of the spinlock, leading to the possibility of this order of
events, and the context being cleared in put_pmu_ctx(), after its
refcount is non zero:
CPU0 CPU1
find_get_pmu_context()
if (!epc->ctx) == false
put_pmu_ctx()
atomic_dec_and_test(&epc->refcount) == true
epc->refcount == 0
atomic_inc(&epc->refcount);
epc->refcount == 1
list_del_init(&epc->pmu_ctx_entry);
epc->ctx = NULL;
Another issue is that WARN_ON for no active PMU events in put_pmu_ctx()
is outside of the lock. If the perf_event_pmu_context is an embedded
one, even after clearing it, it won't be deleted and can be re-used. So
the warning can trigger. For this reason it also needs to be moved
inside the lock.
The above warning is very quick to trigger on Arm by running these two
commands at the same time:
while true; do perf record -- ls; done
while true; do perf record -- ls; done
[peterz: atomic_dec_and_raw_lock*()]
Fixes: bd27568117 ("perf: Rewrite core context handling")
Reported-by: syzbot+697196bc0265049822bd@syzkaller.appspotmail.com
Signed-off-by: James Clark <james.clark@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ravi Bangoria <ravi.bangoria@amd.com>
Link: https://lore.kernel.org/r/20230127143141.1782804-2-james.clark@arm.com
avoid leaking memory
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Merge tag 'irq_urgent_for_v6.2_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq fix from Borislav Petkov:
- Cleanup the firmware node for the new IRQ MSI domain properly, to
avoid leaking memory
* tag 'irq_urgent_for_v6.2_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
genirq/msi: Free the fwnode created by msi_create_device_irq_domain()
s390x eBPF JIT needs to know whether a function return value is signed
and which function arguments are signed, in order to generate code
compliant with the s390x ABI.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20230128000650.1516334-26-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
iterators.lskel.h is little-endian, therefore bpf iterator is currently
broken on big-endian systems. Introduce a big-endian version and add
instructions regarding its generation. Unfortunately bpftool's
cross-endianness capabilities are limited to BTF right now, so the
procedure requires access to a big-endian machine or a configured
emulator.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20230128000650.1516334-25-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The first element of a struct bpf_cpumask is a cpumask_t. This is done
to allow struct bpf_cpumask to be cast to a struct cpumask. If this
element were ever moved to another field, any BPF program passing a
struct bpf_cpumask * to a kfunc expecting a const struct cpumask * would
immediately fail to load. Add a build-time assertion so this is
assumption is captured and verified.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230128141537.100777-1-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:
====================
bpf-next 2023-01-28
We've added 124 non-merge commits during the last 22 day(s) which contain
a total of 124 files changed, 6386 insertions(+), 1827 deletions(-).
The main changes are:
1) Implement XDP hints via kfuncs with initial support for RX hash and
timestamp metadata kfuncs, from Stanislav Fomichev and
Toke Høiland-Jørgensen.
Measurements on overhead: https://lore.kernel.org/bpf/875yellcx6.fsf@toke.dk
2) Extend libbpf's bpf_tracing.h support for tracing arguments of
kprobes/uprobes and syscall as a special case, from Andrii Nakryiko.
3) Significantly reduce the search time for module symbols by livepatch
and BPF, from Jiri Olsa and Zhen Lei.
4) Enable cpumasks to be used as kptrs, which is useful for tracing
programs tracking which tasks end up running on which CPUs
in different time intervals, from David Vernet.
5) Fix several issues in the dynptr processing such as stack slot liveness
propagation, missing checks for PTR_TO_STACK variable offset, etc,
from Kumar Kartikeya Dwivedi.
6) Various performance improvements, fixes, and introduction of more
than just one XDP program to XSK selftests, from Magnus Karlsson.
7) Big batch to BPF samples to reduce deprecated functionality,
from Daniel T. Lee.
8) Enable struct_ops programs to be sleepable in verifier,
from David Vernet.
9) Reduce pr_warn() noise on BTF mismatches when they are expected under
the CONFIG_MODULE_ALLOW_BTF_MISMATCH config anyway, from Connor O'Brien.
10) Describe modulo and division by zero behavior of the BPF runtime
in BPF's instruction specification document, from Dave Thaler.
11) Several improvements to libbpf API documentation in libbpf.h,
from Grant Seltzer.
12) Improve resolve_btfids header dependencies related to subcmd and add
proper support for HOSTCC, from Ian Rogers.
13) Add ipip6 and ip6ip decapsulation support for bpf_skb_adjust_room()
helper along with BPF selftests, from Ziyang Xuan.
14) Simplify the parsing logic of structure parameters for BPF trampoline
in the x86-64 JIT compiler, from Pu Lehui.
15) Get BTF working for kernels with CONFIG_RUST enabled by excluding
Rust compilation units with pahole, from Martin Rodriguez Reboredo.
16) Get bpf_setsockopt() working for kTLS on top of TCP sockets,
from Kui-Feng Lee.
17) Disable stack protection for BPF objects in bpftool given BPF backends
don't support it, from Holger Hoffstätte.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (124 commits)
selftest/bpf: Make crashes more debuggable in test_progs
libbpf: Add documentation to map pinning API functions
libbpf: Fix malformed documentation formatting
selftests/bpf: Properly enable hwtstamp in xdp_hw_metadata
selftests/bpf: Calls bpf_setsockopt() on a ktls enabled socket.
bpf: Check the protocol of a sock to agree the calls to bpf_setsockopt().
bpf/selftests: Verify struct_ops prog sleepable behavior
bpf: Pass const struct bpf_prog * to .check_member
libbpf: Support sleepable struct_ops.s section
bpf: Allow BPF_PROG_TYPE_STRUCT_OPS programs to be sleepable
selftests/bpf: Fix vmtest static compilation error
tools/resolve_btfids: Alter how HOSTCC is forced
tools/resolve_btfids: Install subcmd headers
bpf/docs: Document the nocast aliasing behavior of ___init
bpf/docs: Document how nested trusted fields may be defined
bpf/docs: Document cpumask kfuncs in a new file
selftests/bpf: Add selftest suite for cpumask kfuncs
selftests/bpf: Add nested trust selftests suite
bpf: Enable cpumasks to be queried and used as kptrs
bpf: Disallow NULLable pointers for trusted kfuncs
...
====================
Link: https://lore.kernel.org/r/20230128004827.21371-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Daniel Borkmann says:
====================
bpf 2023-01-27
We've added 10 non-merge commits during the last 9 day(s) which contain
a total of 10 files changed, 170 insertions(+), 59 deletions(-).
The main changes are:
1) Fix preservation of register's parent/live fields when copying
range-info, from Eduard Zingerman.
2) Fix an off-by-one bug in bpf_mem_cache_idx() to select the right
cache, from Hou Tao.
3) Fix stack overflow from infinite recursion in sock_map_close(),
from Jakub Sitnicki.
4) Fix missing btf_put() in register_btf_id_dtor_kfuncs()'s error path,
from Jiri Olsa.
5) Fix a splat from bpf_setsockopt() via lsm_cgroup/socket_sock_rcv_skb,
from Kui-Feng Lee.
6) Fix bpf_send_signal[_thread]() helpers to hold a reference on the task,
from Yonghong Song.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
bpf: Fix the kernel crash caused by bpf_setsockopt().
selftests/bpf: Cover listener cloning with progs attached to sockmap
selftests/bpf: Pass BPF skeleton to sockmap_listen ops tests
bpf, sockmap: Check for any of tcp_bpf_prots when cloning a listener
bpf, sockmap: Don't let sock_map_{close,destroy,unhash} call itself
bpf: Add missing btf_put to register_btf_id_dtor_kfuncs
selftests/bpf: Verify copy_register_state() preserves parent/live fields
bpf: Fix to preserve reg parent/live fields when copying range info
bpf: Fix a possible task gone issue with bpf_send_signal[_thread]() helpers
bpf: Fix off-by-one error in bpf_mem_cache_idx()
====================
Link: https://lore.kernel.org/r/20230127215820.4993-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
- Fix filter memory leak by calling ftrace_free_filter()
- Initialize trace_printk() earlier so that ftrace_dump_on_oops shows data
on early crashes.
- Update the outdated instructions in scripts/tracing/ftrace-bisect.sh
- Add lockdep_is_held() to fix lockdep warning
- Add allocation failure check in create_hist_field()
- Don't initialize pointer that gets set right away in enabled_monitors_write()
- Update MAINTAINER entries
- Fix help messages in Kconfigs
- Fix kernel-doc header for update_preds()
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Merge tag 'trace-v6.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:
- Fix filter memory leak by calling ftrace_free_filter()
- Initialize trace_printk() earlier so that ftrace_dump_on_oops shows
data on early crashes.
- Update the outdated instructions in scripts/tracing/ftrace-bisect.sh
- Add lockdep_is_held() to fix lockdep warning
- Add allocation failure check in create_hist_field()
- Don't initialize pointer that gets set right away in enabled_monitors_write()
- Update MAINTAINER entries
- Fix help messages in Kconfigs
- Fix kernel-doc header for update_preds()
* tag 'trace-v6.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
bootconfig: Update MAINTAINERS file to add tree and mailing list
rv: remove redundant initialization of pointer ptr
ftrace: Maintain samples/ftrace
tracing/filter: fix kernel-doc warnings
lib: Kconfig: fix spellos
trace_events_hist: add check for return value of 'create_hist_field'
tracing/osnoise: Use built-in RCU list checking
tracing: Kconfig: Fix spelling/grammar/punctuation
ftrace/scripts: Update the instructions for ftrace-bisect.sh
tracing: Make sure trace_printk() can output as soon as it can be used
ftrace: Export ftrace_free_filter() to modules
The kernel crash was caused by a BPF program attached to the
"lsm_cgroup/socket_sock_rcv_skb" hook, which performed a call to
`bpf_setsockopt()` in order to set the TCP_NODELAY flag as an
example. Flags like TCP_NODELAY can prompt the kernel to flush a
socket's outgoing queue, and this hook
"lsm_cgroup/socket_sock_rcv_skb" is frequently triggered by
softirqs. The issue was that in certain circumstances, when
`tcp_write_xmit()` was called to flush the queue, it would also allow
BH (bottom-half) to run. This could lead to our program attempting to
flush the same socket recursively, which caused a `skbuff` to be
unlinked twice.
`security_sock_rcv_skb()` is triggered by `tcp_filter()`. This occurs
before the sock ownership is checked in `tcp_v4_rcv()`. Consequently,
if a bpf program runs on `security_sock_rcv_skb()` while under softirq
conditions, it may not possess the lock needed for `bpf_setsockopt()`,
thus presenting an issue.
The patch fixes this issue by ensuring that a BPF program attached to
the "lsm_cgroup/socket_sock_rcv_skb" hook is not allowed to call
`bpf_setsockopt()`.
The differences from v1 are
- changing commit log to explain holding the lock of the sock,
- emphasizing that TCP_NODELAY is not the only flag, and
- adding the fixes tag.
v1: https://lore.kernel.org/bpf/20230125000244.1109228-1-kuifeng@meta.com/
Signed-off-by: Kui-Feng Lee <kuifeng@meta.com>
Fixes: 9113d7e48e ("bpf: expose bpf_{g,s}etsockopt to lsm cgroup")
Link: https://lore.kernel.org/r/20230127001732.4162630-1-kuifeng@meta.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
The .check_member field of struct bpf_struct_ops is currently passed the
member's btf_type via const struct btf_type *t, and a const struct
btf_member *member. This allows the struct_ops implementation to check
whether e.g. an ops is supported, but it would be useful to also enforce
that the struct_ops prog being loaded for that member has other
qualities, like being sleepable (or not). This patch therefore updates
the .check_member() callback to also take a const struct bpf_prog *prog
argument.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230125164735.785732-4-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
BPF struct_ops programs currently cannot be marked as sleepable. This
need not be the case -- struct_ops programs can be sleepable, and e.g.
invoke kfuncs that export the KF_SLEEPABLE flag. So as to allow future
struct_ops programs to invoke such kfuncs, this patch updates the
verifier to allow struct_ops programs to be sleepable. A follow-on patch
will add support to libbpf for specifying struct_ops.s as a sleepable
struct_ops program, and then another patch will add testcases to the
dummy_st_ops selftest suite which test sleepable struct_ops behavior.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230125164735.785732-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Now that we've added a series of new cpumask kfuncs, we should document
them so users can easily use them. This patch adds a new cpumasks.rst
file to document them.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230125143816.721952-6-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Certain programs may wish to be able to query cpumasks. For example, if
a program that is tracing percpu operations wishes to track which tasks
end up running on which CPUs, it could be useful to associate that with
the tasks' cpumasks. Similarly, programs tracking NUMA allocations, CPU
scheduling domains, etc, could potentially benefit from being able to
see which CPUs a task could be migrated to.
This patch enables these types of use cases by introducing a series of
bpf_cpumask_* kfuncs. Amongst these kfuncs, there are two separate
"classes" of operations:
1. kfuncs which allow the caller to allocate and mutate their own
cpumask kptrs in the form of a struct bpf_cpumask * object. Such
kfuncs include e.g. bpf_cpumask_create() to allocate the cpumask, and
bpf_cpumask_or() to mutate it. "Regular" cpumasks such as p->cpus_ptr
may not be passed to these kfuncs, and the verifier will ensure this
is the case by comparing BTF IDs.
2. Read-only operations which operate on const struct cpumask *
arguments. For example, bpf_cpumask_test_cpu(), which tests whether a
CPU is set in the cpumask. Any trusted struct cpumask * or struct
bpf_cpumask * may be passed to these kfuncs. The verifier allows
struct bpf_cpumask * even though the kfunc is defined with struct
cpumask * because the first element of a struct bpf_cpumask is a
cpumask_t, so it is safe to cast.
A follow-on patch will add selftests which validate these kfuncs, and
another will document them.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230125143816.721952-3-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
KF_TRUSTED_ARGS kfuncs currently have a subtle and insidious bug in
validating pointers to scalars. Say that you have a kfunc like the
following, which takes an array as the first argument:
bool bpf_cpumask_empty(const struct cpumask *cpumask)
{
return cpumask_empty(cpumask);
}
...
BTF_ID_FLAGS(func, bpf_cpumask_empty, KF_TRUSTED_ARGS)
...
If a BPF program were to invoke the kfunc with a NULL argument, it would
crash the kernel. The reason is that struct cpumask is defined as a
bitmap, which is itself defined as an array, and is accessed as a memory
address by bitmap operations. So when the verifier analyzes the
register, it interprets it as a pointer to a scalar struct, which is an
array of size 8. check_mem_reg() then sees that the register is NULL and
returns 0, and the kfunc crashes when it passes it down to the cpumask
wrappers.
To fix this, this patch adds a check for KF_ARG_PTR_TO_MEM which
verifies that the register doesn't contain a possibly-NULL pointer if
the kfunc is KF_TRUSTED_ARGS.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230125143816.721952-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The pointer ptr is being initialized with a value that is never read,
it is being updated later on a call to strim. Remove the extraneous
initialization.
Link: https://lkml.kernel.org/r/20230116161612.77192-1-colin.i.king@gmail.com
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Use the 'struct' keyword for a struct's kernel-doc notation and
use the correct function parameter name to eliminate kernel-doc
warnings:
kernel/trace/trace_events_filter.c:136: warning: cannot understand function prototype: 'struct prog_entry '
kerne/trace/trace_events_filter.c:155: warning: Excess function parameter 'when_to_branch' description in 'update_preds'
Also correct some trivial punctuation problems.
Link: https://lkml.kernel.org/r/20230108021238.16398-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When validating BTF types for KF_TRUSTED_ARGS kfuncs, the verifier
currently enforces that the top-level type must match when calling
the kfunc. In other words, the verifier does not allow the BPF program
to pass a bitwise equivalent struct, despite it being allowed according
to the C standard.
For example, if you have the following type:
struct nf_conn___init {
struct nf_conn ct;
};
The C standard stipulates that it would be safe to pass a struct
nf_conn___init to a kfunc expecting a struct nf_conn. The verifier
currently disallows this, however, as semantically kfuncs may want to
enforce that structs that have equivalent types according to the C
standard, but have different BTF IDs, are not able to be passed to
kfuncs expecting one or the other. For example, struct nf_conn___init
may not be queried / looked up, as it is allocated but may not yet be
fully initialized.
On the other hand, being able to pass types that are equivalent
according to the C standard will be useful for other types of kfunc /
kptrs enabled by BPF. For example, in a follow-on patch, a series of
kfuncs will be added which allow programs to do bitwise queries on
cpumasks that are either allocated by the program (in which case they'll
be a 'struct bpf_cpumask' type that wraps a cpumask_t as its first
element), or a cpumask that was allocated by the main kernel (in which
case it will just be a straight cpumask_t, as in task->cpus_ptr).
Having the two types of cpumasks allows us to distinguish between the
two for when a cpumask is read-only vs. mutatable. A struct bpf_cpumask
can be mutated by e.g. bpf_cpumask_clear(), whereas a regular cpumask_t
cannot be. On the other hand, a struct bpf_cpumask can of course be
queried in the exact same manner as a cpumask_t, with e.g.
bpf_cpumask_test_cpu().
If we were to enforce that top level types match, then a user that's
passing a struct bpf_cpumask to a read-only cpumask_t argument would
have to cast with something like bpf_cast_to_kern_ctx() (which itself
would need to be updated to expect the alias, and currently it only
accommodates a single alias per prog type). Additionally, not specifying
KF_TRUSTED_ARGS is not an option, as some kfuncs take one argument as a
struct bpf_cpumask *, and another as a struct cpumask *
(i.e. cpumask_t).
In order to enable this, this patch relaxes the constraint that a
KF_TRUSTED_ARGS kfunc must have strict type matching, and instead only
enforces strict type matching if a type is observed to be a "no-cast
alias" (i.e., that the type names are equivalent, but one is suffixed
with ___init).
Additionally, in order to try and be conservative and match existing
behavior / expectations, this patch also enforces strict type checking
for acquire kfuncs. We were already enforcing it for release kfuncs, so
this should also improve the consistency of the semantics for kfuncs.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230120192523.3650503-3-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In kfuncs, a "trusted" pointer is a pointer that the kfunc can assume is
safe, and which the verifier will allow to be passed to a
KF_TRUSTED_ARGS kfunc. Currently, a KF_TRUSTED_ARGS kfunc disallows any
pointer to be passed at a nonzero offset, but sometimes this is in fact
safe if the "nested" pointer's lifetime is inherited from its parent.
For example, the const cpumask_t *cpus_ptr field in a struct task_struct
will remain valid until the task itself is destroyed, and thus would
also be safe to pass to a KF_TRUSTED_ARGS kfunc.
While it would be conceptually simple to enable this by using BTF tags,
gcc unfortunately does not yet support this. In the interim, this patch
enables support for this by using a type-naming convention. A new
BTF_TYPE_SAFE_NESTED macro is defined in verifier.c which allows a
developer to specify the nested fields of a type which are considered
trusted if its parent is also trusted. The verifier is also updated to
account for this. A patch with selftests will be added in a follow-on
change, along with documentation for this feature.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230120192523.3650503-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Function 'create_hist_field' is called recursively at
trace_events_hist.c:1954 and can return NULL-value that's why we have
to check it to avoid null pointer dereference.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Link: https://lkml.kernel.org/r/20230111120409.4111-1-n.petrova@fintech.ru
Cc: stable@vger.kernel.org
Fixes: 30350d65ac ("tracing: Add variable support to hist triggers")
Signed-off-by: Natalia Petrova <n.petrova@fintech.ru>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
list_for_each_entry_rcu() has built-in RCU and lock checking.
Pass cond argument to list_for_each_entry_rcu() to silence false lockdep
warning when CONFIG_PROVE_RCU_LIST is enabled.
Execute as follow:
[tracing]# echo osnoise > current_tracer
[tracing]# echo 1 > tracing_on
[tracing]# echo 0 > tracing_on
The trace_types_lock is held when osnoise_tracer_stop() or
timerlat_tracer_stop() are called in the non-RCU read side section.
So, pass lockdep_is_held(&trace_types_lock) to silence false lockdep
warning.
Link: https://lkml.kernel.org/r/20221227023036.784337-1-nashuiliang@gmail.com
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: dae181349f ("tracing/osnoise: Support a list of trace_array *tr")
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Chuang Wang <nashuiliang@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Eduard Zingerman