Kernel commit 88903c4643 ("tracing/probe: Add ustring type for user-space string")
adds support for user-space strings when type 'ustring' is specified.
Here is an example using sysfs command line interface
for kprobes:
Function to probe:
struct filename *
getname_flags(const char __user *filename, int flags, int *empty)
Setup:
# cd /sys/kernel/debug/tracing/
# echo 'p:tmr1 getname_flags +0(%r2):ustring' > kprobe_events
# cat events/kprobes/tmr1/format | fgrep print
print fmt: "(%lx) arg1=\"%s\"", REC->__probe_ip, REC->arg1
# echo 1 > events/kprobes/tmr1/enable
# touch /tmp/111
# echo 0 > events/kprobes/tmr1/enable
# cat trace|fgrep /tmp/111
touch-5846 [005] d..2 255520.717960: tmr1:\
(getname_flags+0x0/0x400) arg1="/tmp/111"
Doing the same with the perf tool fails.
Using type 'string' succeeds:
# perf probe "vfs_getname=getname_flags:72 pathname=filename:string"
Added new event:
probe:vfs_getname (on getname_flags:72 with pathname=filename:string)
....
# perf probe -d probe:vfs_getname
Removed event: probe:vfs_getname
However using type 'ustring' fails (output before):
# perf probe "vfs_getname=getname_flags:72 pathname=filename:ustring"
Failed to write event: Invalid argument
Error: Failed to add events.
#
Fix this by adding type 'ustring' in function
convert_variable_type().
Using ustring succeeds (output after):
# ./perf probe "vfs_getname=getname_flags:72 pathname=filename:ustring"
Added new event:
probe:vfs_getname (on getname_flags:72 with pathname=filename:ustring)
You can now use it in all perf tools, such as:
perf record -e probe:vfs_getname -aR sleep 1
#
Note: This issue also exists on x86, it is not s390 specific.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: sumanthk@linux.ibm.com
Link: http://lore.kernel.org/lkml/20200120132011.64698-2-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
There is a spelling mistake in a pr_warning message. Fix it.
Signed-off-by: Colin King <colin.king@canonical.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-janitors@vger.kernel.org
Link: http://lore.kernel.org/lkml/20191121092623.374896-1-colin.king@canonical.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Trace a magic number as immediate value if the target variable is not
found at some probe points which is based on one probe event.
This feature is good for the case if you trace a source code line with
some local variables, which is compiled into several instructions and
some of the variables are optimized out on some instructions.
Even if so, with this feature, perf probe trace a magic number instead
of such disappeared variables and fold those probes on one event.
E.g. without this patch:
# perf probe -D "pud_page_vaddr pud"
Failed to find 'pud' in this function.
Failed to find 'pud' in this function.
Failed to find 'pud' in this function.
Failed to find 'pud' in this function.
Failed to find 'pud' in this function.
Failed to find 'pud' in this function.
Failed to find 'pud' in this function.
Failed to find 'pud' in this function.
Failed to find 'pud' in this function.
Failed to find 'pud' in this function.
Failed to find 'pud' in this function.
Failed to find 'pud' in this function.
Failed to find 'pud' in this function.
Failed to find 'pud' in this function.
Failed to find 'pud' in this function.
Failed to find 'pud' in this function.
p:probe/pud_page_vaddr _text+23480787 pud=%ax:x64
p:probe/pud_page_vaddr _text+23808453 pud=%bp:x64
p:probe/pud_page_vaddr _text+23558082 pud=%ax:x64
p:probe/pud_page_vaddr _text+328373 pud=%r8:x64
p:probe/pud_page_vaddr _text+348448 pud=%bx:x64
p:probe/pud_page_vaddr _text+23816818 pud=%bx:x64
With this patch:
# perf probe -D "pud_page_vaddr pud" | head
spurious_kernel_fault is blacklisted function, skip it.
vmalloc_fault is blacklisted function, skip it.
p:probe/pud_page_vaddr _text+23480787 pud=%ax:x64
p:probe/pud_page_vaddr _text+149051 pud=\deade12d:x64
p:probe/pud_page_vaddr _text+23808453 pud=%bp:x64
p:probe/pud_page_vaddr _text+315926 pud=\deade12d:x64
p:probe/pud_page_vaddr _text+23807209 pud=\deade12d:x64
p:probe/pud_page_vaddr _text+23557365 pud=%ax:x64
p:probe/pud_page_vaddr _text+314097 pud=%di:x64
p:probe/pud_page_vaddr _text+314015 pud=\deade12d:x64
p:probe/pud_page_vaddr _text+313893 pud=\deade12d:x64
p:probe/pud_page_vaddr _text+324083 pud=\deade12d:x64
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Link: http://lore.kernel.org/lkml/157406476931.24476.6261475888681844285.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Support DW_AT_const_value for variable assignment instead of location.
Note that this requires ftrace supporting immediate value.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Link: http://lore.kernel.org/lkml/157406476012.24476.16096289871757175775.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Since perf probe -L shows non representive lines, it can be mislead
users where user can put probes. This prevents to show such non
representive lines so that user can understand which lines user can
probe.
# perf probe -L kernel_read
<kernel_read@/build/linux-pvZVvI/linux-5.0.0/fs/read_write.c:0>
0 ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
{
2 mm_segment_t old_fs;
ssize_t result;
old_fs = get_fs();
6 set_fs(get_ds());
/* The cast to a user pointer is valid due to the set_fs() */
8 result = vfs_read(file, (void __user *)buf, count, pos);
9 set_fs(old_fs);
10 return result;
}
EXPORT_SYMBOL(kernel_read);
Committer testing:
Before:
# perf probe -L kernel_read
<kernel_read@/usr/src/debug/kernel-5.3.fc30/linux-5.3.8-200.fc30.x86_64/fs/read_write.c:0>
0 ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
1 {
2 mm_segment_t old_fs;
3 ssize_t result;
5 old_fs = get_fs();
6 set_fs(KERNEL_DS);
/* The cast to a user pointer is valid due to the set_fs() */
8 result = vfs_read(file, (void __user *)buf, count, pos);
9 set_fs(old_fs);
10 return result;
}
EXPORT_SYMBOL(kernel_read);
#
See the 1, 3, 5 lines? They shouldn't be there, after this patch:
# perf probe -L kernel_read
<kernel_read@/usr/src/debug/kernel-5.3.fc30/linux-5.3.8-200.fc30.x86_64/fs/read_write.c:0>
0 ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
{
2 mm_segment_t old_fs;
ssize_t result;
old_fs = get_fs();
6 set_fs(KERNEL_DS);
/* The cast to a user pointer is valid due to the set_fs() */
8 result = vfs_read(file, (void __user *)buf, count, pos);
9 set_fs(old_fs);
10 return result;
}
EXPORT_SYMBOL(kernel_read);
#
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Link: http://lore.kernel.org/lkml/157406473064.24476.2913278267727587314.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Verify user given probe line is a representive line (which doesn't share
the address with other lines or the line is the least line among the
lines which shares same address), and if not, it shows what is the
representive line.
Without this fix, user can put a probe on the lines which is not a a
representive line. But since this is not a representive line, perf probe
-l shows a representive line number instead of user given line number.
e.g. (put kernel_read:3, but listed as kernel_read:2)
# perf probe -a kernel_read:3
Added new event:
probe:kernel_read (on kernel_read:3)
You can now use it in all perf tools, such as:
perf record -e probe:kernel_read -aR sleep 1
# perf probe -l
probe:kernel_read (on kernel_read:2@linux-5.0.0/fs/read_write.c)
With this fix, perf probe doesn't allow user to put a probe on a
representive line, and tell what is the representive line.
# perf probe -a kernel_read:3
This line is sharing the addrees with other lines.
Please try to probe at kernel_read:2 instead.
Error: Failed to add events.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Link: http://lore.kernel.org/lkml/157406472071.24476.14915451439785001021.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Since debuginfo__find_probes() callback function can be called with the
location which already passed, the callback function must filter out
such overlapped locations.
add_probe_trace_event() has already done it by commit 1a375ae765
("perf probe: Skip same probe address for a given line"), but
add_available_vars() doesn't. Thus perf probe -v shows same address
repeatedly as below:
# perf probe -V vfs_read:18
Available variables at vfs_read:18
@<vfs_read+217>
char* buf
loff_t* pos
ssize_t ret
struct file* file
@<vfs_read+217>
char* buf
loff_t* pos
ssize_t ret
struct file* file
@<vfs_read+226>
char* buf
loff_t* pos
ssize_t ret
struct file* file
With this fix, perf probe -V shows it correctly:
# perf probe -V vfs_read:18
Available variables at vfs_read:18
@<vfs_read+217>
char* buf
loff_t* pos
ssize_t ret
struct file* file
@<vfs_read+226>
char* buf
loff_t* pos
ssize_t ret
struct file* file
Fixes: cf6eb489e5 ("perf probe: Show accessible local variables")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/157241938927.32002.4026859017790562751.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Make find_best_scope() returns innermost DIE at given address if there
is no best matched scope DIE. Since Gcc sometimes generates intuitively
strange line info which is out of inlined function address range, we
need this fixup.
Without this, sometimes perf probe failed to probe on a line inside an
inlined function:
# perf probe -D ksys_open:3
Failed to find scope of probe point.
Error: Failed to add events.
With this fix, 'perf probe' can probe it:
# perf probe -D ksys_open:3
p:probe/ksys_open _text+25707308
p:probe/ksys_open_1 _text+25710596
p:probe/ksys_open_2 _text+25711114
p:probe/ksys_open_3 _text+25711343
p:probe/ksys_open_4 _text+25714058
p:probe/ksys_open_5 _text+2819653
p:probe/ksys_open_6 _text+2819701
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Link: http://lore.kernel.org/lkml/157291300887.19771.14936015360963292236.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Since debuginfo__find_probe_point() uses dwarf_entrypc() for finding the
entry address of the function on which a probe is, it will fail when the
function DIE has only ranges attribute.
To fix this issue, use die_entrypc() instead of dwarf_entrypc().
Without this fix, perf probe -l shows incorrect offset:
# perf probe -l
probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask+18446744071579263632@work/linux/linux/kernel/cpu.c)
probe:clear_tasks_mm_cpumask_1 (on clear_tasks_mm_cpumask+18446744071579263752@work/linux/linux/kernel/cpu.c)
With this:
# perf probe -l
probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask@work/linux/linux/kernel/cpu.c)
probe:clear_tasks_mm_cpumask_1 (on clear_tasks_mm_cpumask:21@work/linux/linux/kernel/cpu.c)
Committer testing:
Before:
[root@quaco ~]# perf probe -l
probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask+18446744071579765152@kernel/cpu.c)
[root@quaco ~]#
After:
[root@quaco ~]# perf probe -l
probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask@kernel/cpu.c)
[root@quaco ~]#
Fixes: 1d46ea2a6a ("perf probe: Fix listing incorrect line number with inline function")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/157199321227.8075.14655572419136993015.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Fix perf probe to probe an inlne function which has no entry pc
or low pc but only has ranges attribute.
This seems very rare case, but I could find a few examples, as
same as probe_point_search_cb(), use die_entrypc() to get the
entry address in probe_point_inline_cb() too.
Without this patch:
# perf probe -D __amd_put_nb_event_constraints
Failed to get entry address of __amd_put_nb_event_constraints.
Probe point '__amd_put_nb_event_constraints' not found.
Error: Failed to add events.
With this patch:
# perf probe -D __amd_put_nb_event_constraints
p:probe/__amd_put_nb_event_constraints amd_put_event_constraints+43
Committer testing:
Before:
[root@quaco ~]# perf probe -D __amd_put_nb_event_constraints
Failed to get entry address of __amd_put_nb_event_constraints.
Probe point '__amd_put_nb_event_constraints' not found.
Error: Failed to add events.
[root@quaco ~]#
After:
[root@quaco ~]# perf probe -D __amd_put_nb_event_constraints
p:probe/__amd_put_nb_event_constraints _text+33789
[root@quaco ~]#
Fixes: 4ea42b1814 ("perf: Add perf probe subcommand, a kprobe-event setup helper")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/157199320336.8075.16189530425277588587.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Fix 'perf probe' to probe a function which has no entry pc or low pc but
only has ranges attribute.
probe_point_search_cb() uses dwarf_entrypc() to get the probe address,
but that doesn't work for the function DIE which has only ranges
attribute. Use die_entrypc() instead.
Without this fix:
# perf probe -k ../build-x86_64/vmlinux -D clear_tasks_mm_cpumask:0
Probe point 'clear_tasks_mm_cpumask' not found.
Error: Failed to add events.
With this:
# perf probe -k ../build-x86_64/vmlinux -D clear_tasks_mm_cpumask:0
p:probe/clear_tasks_mm_cpumask clear_tasks_mm_cpumask+0
Committer testing:
Before:
[root@quaco ~]# perf probe clear_tasks_mm_cpumask:0
Probe point 'clear_tasks_mm_cpumask' not found.
Error: Failed to add events.
[root@quaco ~]#
After:
[root@quaco ~]# perf probe clear_tasks_mm_cpumask:0
Added new event:
probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask)
You can now use it in all perf tools, such as:
perf record -e probe:clear_tasks_mm_cpumask -aR sleep 1
[root@quaco ~]#
Using it with 'perf trace':
[root@quaco ~]# perf trace -e probe:clear_tasks_mm_cpumask
Doesn't seem to be used in x86_64:
$ find . -name "*.c" | xargs grep clear_tasks_mm_cpumask
./kernel/cpu.c: * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU
./kernel/cpu.c:void clear_tasks_mm_cpumask(int cpu)
./arch/xtensa/kernel/smp.c: clear_tasks_mm_cpumask(cpu);
./arch/csky/kernel/smp.c: clear_tasks_mm_cpumask(cpu);
./arch/sh/kernel/smp.c: clear_tasks_mm_cpumask(cpu);
./arch/arm/kernel/smp.c: clear_tasks_mm_cpumask(cpu);
./arch/powerpc/mm/nohash/mmu_context.c: clear_tasks_mm_cpumask(cpu);
$ find . -name "*.h" | xargs grep clear_tasks_mm_cpumask
./include/linux/cpu.h:void clear_tasks_mm_cpumask(int cpu);
$ find . -name "*.S" | xargs grep clear_tasks_mm_cpumask
$
Fixes: e1ecbbc3fa ("perf probe: Fix to handle optimized not-inlined functions")
Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/157199319438.8075.4695576954550638618.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Since there are some DIE which has only ranges instead of the
combination of entrypc/highpc, address verification must use
dwarf_haspc() instead of dwarf_entrypc/dwarf_highpc.
Also, the ranges only DIE will have a partial code in different section
(e.g. unlikely code will be in text.unlikely as "FUNC.cold" symbol). In
that case, we can not use dwarf_entrypc() or die_entrypc(), because the
offset from original DIE can be a minus value.
Instead, this simply gets the symbol and offset from symtab.
Without this patch;
# perf probe -D clear_tasks_mm_cpumask:1
Failed to get entry address of clear_tasks_mm_cpumask
Error: Failed to add events.
And with this patch:
# perf probe -D clear_tasks_mm_cpumask:1
p:probe/clear_tasks_mm_cpumask clear_tasks_mm_cpumask+0
p:probe/clear_tasks_mm_cpumask_1 clear_tasks_mm_cpumask+5
p:probe/clear_tasks_mm_cpumask_2 clear_tasks_mm_cpumask+8
p:probe/clear_tasks_mm_cpumask_3 clear_tasks_mm_cpumask+16
p:probe/clear_tasks_mm_cpumask_4 clear_tasks_mm_cpumask+82
Committer testing:
I managed to reproduce the above:
[root@quaco ~]# perf probe -D clear_tasks_mm_cpumask:1
p:probe/clear_tasks_mm_cpumask _text+919968
p:probe/clear_tasks_mm_cpumask_1 _text+919973
p:probe/clear_tasks_mm_cpumask_2 _text+919976
[root@quaco ~]#
But then when trying to actually put the probe in place, it fails if I
use :0 as the offset:
[root@quaco ~]# perf probe -L clear_tasks_mm_cpumask | head -5
<clear_tasks_mm_cpumask@/usr/src/debug/kernel-5.2.fc30/linux-5.2.18-200.fc30.x86_64/kernel/cpu.c:0>
0 void clear_tasks_mm_cpumask(int cpu)
1 {
2 struct task_struct *p;
[root@quaco ~]# perf probe clear_tasks_mm_cpumask:0
Probe point 'clear_tasks_mm_cpumask' not found.
Error: Failed to add events.
[root@quaco
The next patch is needed to fix this case.
Fixes: 576b523721 ("perf probe: Fix probing symbols with optimization suffix")
Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/157199318513.8075.10463906803299647907.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Fix to skip making a same probe address on given line.
Since a DWARF line info contains several entries for one line with
different column, perf probe will make a different probe on same address
if user specifies a probe point by "function:line" or "file:line".
e.g.
$ perf probe -D kernel_read:8
p:probe/kernel_read_L8 kernel_read+39
p:probe/kernel_read_L8_1 kernel_read+39
This skips such duplicated probe addresses.
Committer testing:
# uname -a
Linux quaco 5.3.0+ #2 SMP Thu Sep 19 16:13:22 -03 2019 x86_64 x86_64 x86_64 GNU/Linux
#
Before:
# perf probe -D kernel_read:8
p:probe/kernel_read _text+3115191
p:probe/kernel_read_1 _text+3115191
#
After:
# perf probe -D kernel_read:8
p:probe/kernel_read _text+3115191
#
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lore.kernel.org/lkml/156886447061.10772.4261569305869149178.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
All we need there is a forward declaration for 'union perf_event', so
remove it from there and add missing header directives in places using
things from this indirect include.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-7ftk0ztstqub1tirjj8o8xbl@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
- Add user space specific memory reading for kprobes
- Allow kprobes to be executed earlier in boot
The rest are mostly just various clean ups and small fixes.
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Merge tag 'trace-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"The main changes in this release include:
- Add user space specific memory reading for kprobes
- Allow kprobes to be executed earlier in boot
The rest are mostly just various clean ups and small fixes"
* tag 'trace-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (33 commits)
tracing: Make trace_get_fields() global
tracing: Let filter_assign_type() detect FILTER_PTR_STRING
tracing: Pass type into tracing_generic_entry_update()
ftrace/selftest: Test if set_event/ftrace_pid exists before writing
ftrace/selftests: Return the skip code when tracing directory not configured in kernel
tracing/kprobe: Check registered state using kprobe
tracing/probe: Add trace_event_call accesses APIs
tracing/probe: Add probe event name and group name accesses APIs
tracing/probe: Add trace flag access APIs for trace_probe
tracing/probe: Add trace_event_file access APIs for trace_probe
tracing/probe: Add trace_event_call register API for trace_probe
tracing/probe: Add trace_probe init and free functions
tracing/uprobe: Set print format when parsing command
tracing/kprobe: Set print format right after parsed command
kprobes: Fix to init kprobes in subsys_initcall
tracepoint: Use struct_size() in kmalloc()
ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS
ftrace: Enable trampoline when rec count returns back to one
tracing/kprobe: Do not run kprobe boot tests if kprobe_event is on cmdline
tracing: Make a separate config for trace event self tests
...
Eroding a bit more the tools/perf/util/util.h hodpodge header.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-natazosyn9rwjka25tvcnyi0@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not write to the free software foundation inc
59 temple place suite 330 boston ma 02111 1307 usa
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 1334 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add user memory access attribute for kprobe event arguments.
If a given 'local variable' is in user-space, User can
specify memory access method by '@user' suffix. This is
not only for string but also for data structure.
If we access a field of data structure in user memory from
kernel on some arch, it will fail. e.g.
perf probe -a "sched_setscheduler param->sched_priority"
This will fail to access the "param->sched_priority" because
the param is __user pointer. Instead, we can now specify
@user suffix for such argument.
perf probe -a "sched_setscheduler param->sched_priority@user"
Note that kernel memory access with "@user" must always fail
on any arch.
Link: http://lkml.kernel.org/r/155789874562.26965.10836126971405890891.stgit@devnote2
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Current 'perf probe' converts the type of array-elements incorrectly. It
always converts the types as a pointer of array. This passes the "array"
type DIE to the type converter so that it can get correct "element of
array" type DIE from it.
E.g.
====
$ cat hello.c
#include <stdio.h>
void foo(int a[])
{
printf("%d\n", a[1]);
}
void main()
{
int a[3] = {4, 5, 6};
printf("%d\n", a[0]);
foo(a);
}
$ gcc -g hello.c -o hello
$ perf probe -x ./hello -D "foo a[1]"
====
Without this fix, above outputs
====
p:probe_hello/foo /tmp/hello:0x4d3 a=+4(-8(%bp)):u64
====
The "u64" means "int *", but a[1] is "int".
With this,
====
p:probe_hello/foo /tmp/hello:0x4d3 a=+4(-8(%bp)):s32
====
So, "int" correctly converted to "s32"
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: linux-kselftest@vger.kernel.org
Cc: linux-trace-users@vger.kernel.org
Fixes: b2a3c12b74 ("perf probe: Support tracing an entry of array")
Link: http://lkml.kernel.org/r/152129114502.31874.2474068470011496356.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
There are places where we just need a forward declaration, and others
were we need to include strlist.h and/or strfilter.h, reducing the
impact of changes in headers on the build time, do it.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-zab42gbiki88y9k0csorxekb@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Moving them from util.h, where they don't belong. Since libc already
have string.h, name it slightly differently, as string2.h.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-eh3vz5sqxsrdd8lodoro4jrw@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Needed to use the PRI[xu](32,64) formatting macros.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-wkbho8kaw24q67dd11q0j39f@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Fix typos and add the following to the scripts/spelling.txt:
an union||a union
Link: http://lkml.kernel.org/r/1481573103-11329-5-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix to probe on gcc generated functions on modules. Since
probing on a module is based on its symbol name, it should
be adjusted on actual symbols.
E.g. without this fix, perf probe shows probe definition
on non-exist symbol as below.
$ perf probe -m build-x86_64/net/netfilter/nf_nat.ko -F in_range*
in_range.isra.12
$ perf probe -m build-x86_64/net/netfilter/nf_nat.ko -D in_range
p:probe/in_range nf_nat:in_range+0
With this fix, perf probe correctly shows a probe on
gcc-generated symbol.
$ perf probe -m build-x86_64/net/netfilter/nf_nat.ko -D in_range
p:probe/in_range nf_nat:in_range.isra.12+0
This also fixes same problem on online module as below.
$ perf probe -m i915 -D assert_plane
p:probe/assert_plane i915:assert_plane.constprop.134+0
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/148411450673.9978.14905987549651656075.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Fix to show correct locations for events on modules by relocating given
address instead of retrying after failure.
This happens when the module text size is big enough, bigger than
sh_addr, because the original code retries with given address + sh_addr
if it failed to find CU DIE at the given address.
Any address smaller than sh_addr always fails and it retries with the
correct address, but addresses bigger than sh_addr will get a CU DIE
which is on the given address (not adjusted by sh_addr).
In my environment(x86-64), the sh_addr of ".text" section is 0x10030.
Since i915 is a huge kernel module, we can see this issue as below.
$ grep "[Tt] .*\[i915\]" /proc/kallsyms | sort | head -n1
ffffffffc0270000 t i915_switcheroo_can_switch [i915]
ffffffffc0270000 + 0x10030 = ffffffffc0280030, so we'll check
symbols cross this boundary.
$ grep "[Tt] .*\[i915\]" /proc/kallsyms | grep -B1 ^ffffffffc028\
| head -n 2
ffffffffc027ff80 t haswell_init_clock_gating [i915]
ffffffffc0280110 t valleyview_init_clock_gating [i915]
So setup probes on both function and see what happen.
$ sudo ./perf probe -m i915 -a haswell_init_clock_gating \
-a valleyview_init_clock_gating
Added new events:
probe:haswell_init_clock_gating (on haswell_init_clock_gating in i915)
probe:valleyview_init_clock_gating (on valleyview_init_clock_gating in i915)
You can now use it in all perf tools, such as:
perf record -e probe:valleyview_init_clock_gating -aR sleep 1
$ sudo ./perf probe -l
probe:haswell_init_clock_gating (on haswell_init_clock_gating@gpu/drm/i915/intel_pm.c in i915)
probe:valleyview_init_clock_gating (on i915_vga_set_decode:4@gpu/drm/i915/i915_drv.c in i915)
As you can see, haswell_init_clock_gating is correctly shown,
but valleyview_init_clock_gating is not.
With this patch, both events are shown correctly.
$ sudo ./perf probe -l
probe:haswell_init_clock_gating (on haswell_init_clock_gating@gpu/drm/i915/intel_pm.c in i915)
probe:valleyview_init_clock_gating (on valleyview_init_clock_gating@gpu/drm/i915/intel_pm.c in i915)
Committer notes:
In my case:
# perf probe -m i915 -a haswell_init_clock_gating -a valleyview_init_clock_gating
Added new events:
probe:haswell_init_clock_gating (on haswell_init_clock_gating in i915)
probe:valleyview_init_clock_gating (on valleyview_init_clock_gating in i915)
You can now use it in all perf tools, such as:
perf record -e probe:valleyview_init_clock_gating -aR sleep 1
# perf probe -l
probe:haswell_init_clock_gating (on i915_getparam+432@gpu/drm/i915/i915_drv.c in i915)
probe:valleyview_init_clock_gating (on __i915_printk+240@gpu/drm/i915/i915_drv.c in i915)
#
# readelf -SW /lib/modules/4.9.0+/build/vmlinux | egrep -w '.text|Name'
[Nr] Name Type Address Off Size ES Flg Lk Inf Al
[ 1] .text PROGBITS ffffffff81000000 200000 822fd3 00 AX 0 0 4096
#
So both are b0rked, now with the fix:
# perf probe -m i915 -a haswell_init_clock_gating -a valleyview_init_clock_gating
Added new events:
probe:haswell_init_clock_gating (on haswell_init_clock_gating in i915)
probe:valleyview_init_clock_gating (on valleyview_init_clock_gating in i915)
You can now use it in all perf tools, such as:
perf record -e probe:valleyview_init_clock_gating -aR sleep 1
# perf probe -l
probe:haswell_init_clock_gating (on haswell_init_clock_gating@gpu/drm/i915/intel_pm.c in i915)
probe:valleyview_init_clock_gating (on valleyview_init_clock_gating@gpu/drm/i915/intel_pm.c in i915)
#
Both looks correct.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/148411436777.9978.1440275861947194930.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Skip probes if the entry address of the target function is 0. This can
happen when we're handling C++ debuginfo files.
E.g. without this fix, below case still fail.
----
$ ./perf probe -x /usr/lib64/libstdc++.so.6 -vD is_open
probe-definition(0): is_open
symbol:is_open file:(null) line:0 offset:0 return:0 lazy:(null)
0 arguments
symbol:catch file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:throw file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:rethrow file:(null) line:0 offset:0 return:0 lazy:(null)
Open Debuginfo file: /usr/lib/debug/usr/lib64/libstdc++.so.6.0.22.debug
Try to find probe point from debuginfo.
Matched function: is_open [295df]
found inline addr: 0x8ca80
Probe point found: is_open+0
found inline addr: 0x8ca70
Probe point found: is_open+0
found inline addr: 0x8ca60
Probe point found: is_open+0
Matched function: is_open [6527f]
Matched function: is_open [9fe8a]
Probe point found: is_open+0
Matched function: is_open [19710b]
found inline addr: 0xecca9
Probe point found: stdio_filebuf+57
found inline addr: 0x0
Probe point found: swap+0
Matched function: is_open [19fc9d]
Probe point found: is_open+0
Found 7 probe_trace_events.
p:probe_libstdc++/is_open /usr/lib64/libstdc++.so.6.0.22:0x8ca80
p:probe_libstdc++/is_open_1 /usr/lib64/libstdc++.so.6.0.22:0x8ca70
p:probe_libstdc++/is_open_2 /usr/lib64/libstdc++.so.6.0.22:0x8ca60
p:probe_libstdc++/is_open_3 /usr/lib64/libstdc++.so.6.0.22:0xb0ad0
p:probe_libstdc++/is_open_4 /usr/lib64/libstdc++.so.6.0.22:0xecca9
Failed to synthesize probe trace event.
Error: Failed to add events. Reason: Invalid argument (Code: -22)
----
This is because some instances have entry_pc == 0 (see 19710b and
19fc9d). With this fix, those are skipped.
----
$ ./perf probe -x /usr/lib64/libstdc++.so.6 -D is_open
p:probe_libstdc++/is_open /usr/lib64/libstdc++.so.6.0.22:0x8ca80
p:probe_libstdc++/is_open_1 /usr/lib64/libstdc++.so.6.0.22:0x8ca70
p:probe_libstdc++/is_open_2 /usr/lib64/libstdc++.so.6.0.22:0x8ca60
p:probe_libstdc++/is_open_3 /usr/lib64/libstdc++.so.6.0.22:0xb0ad0
p:probe_libstdc++/is_open_4 /usr/lib64/libstdc++.so.6.0.22:0xecca9
----
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/147464490707.29804.14277897643725143867.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Ignore the error when the perf probe failed to find inline function
instances. This can happen when we search a method in C++ debuginfo. If
there is completely no instance in target, perf probe can return an
error.
E.g. without this fix:
----
$ perf probe -x /usr/lib64/libstdc++.so.6 -vD showmanyc
probe-definition(0): showmanyc
symbol:showmanyc file:(null) line:0 offset:0 return:0 lazy:(null)
0 arguments
symbol:catch file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:throw file:(null) line:0 offset:0 return:0 lazy:(null)
symbol:rethrow file:(null) line:0 offset:0 return:0 lazy:(null)
Open Debuginfo file: /usr/lib/debug/usr/lib64/libstdc++.so.6.0.22.debug
Try to find probe point from debuginfo.
Matched function: showmanyc
An error occurred in debuginfo analysis (-2).
Trying to use symbols.
Failed to find symbol showmanyc in /usr/lib64/libstdc++.so.6.0.22
Error: Failed to add events. Reason: No such file or directory (Code: -2)
----
This is because one of showmanyc is defined as inline but no instance
found. With this fix, it is succeeded to show as below.
----
$ perf probe -x /usr/lib64/libstdc++.so.6 -D showmanyc
p:probe_libstdc++/showmanyc /usr/lib64/libstdc++.so.6.0.22:0xb0e50
p:probe_libstdc++/showmanyc_1 /usr/lib64/libstdc++.so.6.0.22:0xc7c40
p:probe_libstdc++/showmanyc_2 /usr/lib64/libstdc++.so.6.0.22:0xecfa0
p:probe_libstdc++/showmanyc_3 /usr/lib64/libstdc++.so.6.0.22:0x115fc0
p:probe_libstdc++/showmanyc_4 /usr/lib64/libstdc++.so.6.0.22:0x121a90
----
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/147464489775.29804.3190419491209875936.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Move generic dwarf related functions from util/probe-finder.c to
util/dwarf-aux.c. Functions name and their prototype are also changed
accordingly. No functionality changes.
Suggested-and-Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1472546377-25612-1-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The function prologue prepares stack and registers before executing
function logic.
When target program is compiled without optimization, function parameter
information is only valid after the prologue.
When we probe entrypc of the function, and try to record a function
parameter, it contains a garbage value.
For example:
$ vim test.c
#include <stdio.h>
void foo(int i)
{
printf("i: %d\n", i);
}
int main()
{
foo(42);
return 0;
}
$ gcc -g test.c -o test
$ objdump -dl test | less
foo():
/home/ravi/test.c:4
400536: 55 push %rbp
400537: 48 89 e5 mov %rsp,%rbp
40053a: 48 83 ec 10 sub -bashx10,%rsp
40053e: 89 7d fc mov %edi,-0x4(%rbp)
/home/ravi/test.c:5
400541: 8b 45 fc mov -0x4(%rbp),%eax
...
...
main():
/home/ravi/test.c:9
400558: 55 push %rbp
400559: 48 89 e5 mov %rsp,%rbp
/home/ravi/test.c:10
40055c: bf 2a 00 00 00 mov -bashx2a,%edi
400561: e8 d0 ff ff ff callq 400536 <foo>
$ perf probe -x ./test 'foo i'
$ cat /sys/kernel/debug/tracing/uprobe_events
p:probe_test/foo /home/ravi/test:0x0000000000000536 i=-12(%sp):s32
$ perf record -e probe_test:foo ./test
$ perf script
test 5778 [001] 4918.562027: probe_test:foo: (400536) i=0
Here variable 'i' is passed via stack which is pushed on stack at
0x40053e. But we are probing at 0x400536.
To resolve this issues, we need to probe on next instruction after
prologue. gdb and systemtap also does same thing. I've implemented this
patch based on approach systemtap has used.
After applying patch:
$ perf probe -x ./test 'foo i'
$ cat /sys/kernel/debug/tracing/uprobe_events
p:probe_test/foo /home/ravi/test:0x0000000000000541 i=-4(%bp):s32
$ perf record -e probe_test:foo ./test
$ perf script
test 6300 [001] 5877.879327: probe_test:foo: (400541) i=42
No need to skip prologue for optimized case since debug info is correct
for each instructions for -O2 -g. For more details please visit:
https://bugzilla.redhat.com/show_bug.cgi?id=612253#c6
Changes in v2:
- Skipping prologue only when any ARG is either C variable, $params or
$vars.
- Probe on line(:1) may not be always possible. Recommend only address
to force probe on function entry.
Committer notes:
Testing it with 'perf trace':
# perf probe -x ./test foo i
Added new event:
probe_test:foo (on foo in /home/acme/c/test with i)
You can now use it in all perf tools, such as:
perf record -e probe_test:foo -aR sleep 1
# cat /sys/kernel/debug/tracing/uprobe_events
p:probe_test/foo /home/acme/c/test:0x0000000000000526 i=-12(%sp):s32
# trace --no-sys --event probe_*:* ./test
i: 42
0.000 probe_test:foo:(400526) i=0)
#
After the patch:
# perf probe -d *:*
Removed event: probe_test:foo
# perf probe -x ./test foo i
Target program is compiled without optimization. Skipping prologue.
Probe on address 0x400526 to force probing at the function entry.
Added new event:
probe_test:foo (on foo in /home/acme/c/test with i)
You can now use it in all perf tools, such as:
perf record -e probe_test:foo -aR sleep 1
# cat /sys/kernel/debug/tracing/uprobe_events
p:probe_test/foo /home/acme/c/test:0x0000000000000531 i=-4(%bp):s32
# trace --no-sys --event probe_*:* ./test
i: 42
0.000 probe_test:foo:(400531) i=42)
#
Reported-by: Michael Petlan <mpetlan@redhat.com>
Report-Link: https://www.mail-archive.com/linux-perf-users@vger.kernel.org/msg02348.html
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1299021
Link: http://lkml.kernel.org/r/1470214725-5023-2-git-send-email-ravi.bangoria@linux.vnet.ibm.com
[ Rename 'die' to 'cu_die' to avoid shadowing a die() definition on at least centos 5, Debian 7 and ubuntu:12.04.5]
[ Use PRIx64 instead of lx to format a Dwarf_Addr, aka long long unsigned int, fixing the build on 32-bit systems ]
[ dwarf_getsrclines() expects a size_t * argument ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Support probing on offline cross-architecture binary by adding getting
the target machine arch from ELF and choose correct register string for
the machine.
Here is an example:
-----
$ perf probe --vmlinux=./vmlinux-arm --definition 'do_sys_open $params'
p:probe/do_sys_open do_sys_open+0 dfd=%r5:s32 filename=%r1:u32 flags=%r6:s32 mode=%r3:u16
-----
Here, we can get probe/do_sys_open from above and append it to to the target
machine's tracing/kprobe_events file in the tracefs mountput, usually
/sys/kernel/debug/tracing/kprobe_events (or /sys/kernel/tracing/kprobe_events).
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/147214229717.23638.6440579792548044658.stgit@devbox
[ Add definition for EM_AARCH64 to fix the build on at least centos 6, debian 7 & ubuntu 12.04.5 ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Use hexadecimal type by default if it is available on current running
kernel.
This keeps the default behavior of perf probe after changing the output
format of 'u8/16/32/64' to unsigned decimal number.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Naohiro Aota <naohiro.aota@hgst.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/147151074685.12957.16415861010796255514.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Support hexadecimal unsigned integer casting by 'x'. This allows user
to explicitly specify the output format of the probe arguments as
hexadecimal.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Naohiro Aota <naohiro.aota@hgst.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/147151072679.12957.4458656416765710753.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add a checking routine what types are supported by the running kernel by
finding the pattern in <debugfs>/tracing/README.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Naohiro Aota <naohiro.aota@hgst.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/147151071172.12957.3340095690753291085.stgit@devbox
[ 'enum probe_type' has no negative entries, so ends up as 'unsigned', remove '< 0'
test to fix the build on at least centos:5, debian:7 & ubuntu:12.04.5 ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The 'perf probe' tool detects a variable's type and use the detected
type to add a new probe. Then, kprobes prints its variable in
hexadecimal format if the variable is unsigned and prints in decimal if
it is signed.
We sometimes want to see unsigned variable in decimal format (i.e.
sector_t or size_t). In that case, we need to investigate the variable's
size manually to specify just signedness.
This patch add signedness casting support. By specifying "s" or "u" as a
type, perf-probe will investigate variable size as usual and use the
specified signedness.
E.g. without this:
$ perf probe -a 'submit_bio bio->bi_iter.bi_sector'
Added new event:
probe:submit_bio (on submit_bio with bi_sector=bio->bi_iter.bi_sector)
You can now use it in all perf tools, such as:
perf record -e probe:submit_bio -aR sleep 1
$ cat trace_pipe|head
dbench-9692 [003] d..1 971.096633: submit_bio: (submit_bio+0x0/0x140) bi_sector=0x3a3d00
dbench-9692 [003] d..1 971.096685: submit_bio: (submit_bio+0x0/0x140) bi_sector=0x1a3d80
dbench-9692 [003] d..1 971.096687: submit_bio: (submit_bio+0x0/0x140) bi_sector=0x3a3d80
...
// need to investigate the variable size
$ perf probe -a 'submit_bio bio->bi_iter.bi_sector:s64'
Added new event:
probe:submit_bio (on submit_bio with bi_sector=bio->bi_iter.bi_sector:s64)
You can now use it in all perf tools, such as:
perf record -e probe:submit_bio -aR sleep 1
With this:
// just use "s" to cast its signedness
$ perf probe -v -a 'submit_bio bio->bi_iter.bi_sector:s'
Added new event:
probe:submit_bio (on submit_bio with bi_sector=bio->bi_iter.bi_sector:s)
You can now use it in all perf tools, such as:
perf record -e probe:submit_bio -aR sleep 1
$ cat trace_pipe|head
dbench-9689 [001] d..1 1212.391237: submit_bio: (submit_bio+0x0/0x140) bi_sector=128
dbench-9689 [001] d..1 1212.391252: submit_bio: (submit_bio+0x0/0x140) bi_sector=131072
dbench-9697 [006] d..1 1212.398611: submit_bio: (submit_bio+0x0/0x140) bi_sector=30208
This commit also update perf-probe.txt to describe "types". Most parts
are based on existing documentation: Documentation/trace/kprobetrace.txt
Committer note:
Testing using 'perf trace':
# perf probe -a 'submit_bio bio->bi_iter.bi_sector'
Added new event:
probe:submit_bio (on submit_bio with bi_sector=bio->bi_iter.bi_sector)
You can now use it in all perf tools, such as:
perf record -e probe:submit_bio -aR sleep 1
# trace --no-syscalls --ev probe:submit_bio
0.000 probe:submit_bio:(ffffffffac3aee00) bi_sector=0xc133c0)
3181.861 probe:submit_bio:(ffffffffac3aee00) bi_sector=0x6cffb8)
3181.881 probe:submit_bio:(ffffffffac3aee00) bi_sector=0x6cffc0)
3184.488 probe:submit_bio:(ffffffffac3aee00) bi_sector=0x6cffc8)
<SNIP>
4717.927 probe:submit_bio:(ffffffffac3aee00) bi_sector=0x4dc7a88)
4717.970 probe:submit_bio:(ffffffffac3aee00) bi_sector=0x4dc7880)
^C[root@jouet ~]#
Now, using this new feature:
[root@jouet ~]# perf probe -a 'submit_bio bio->bi_iter.bi_sector:s'
Added new event:
probe:submit_bio (on submit_bio with bi_sector=bio->bi_iter.bi_sector:s)
You can now use it in all perf tools, such as:
perf record -e probe:submit_bio -aR sleep 1
[root@jouet ~]# trace --no-syscalls --ev probe:submit_bio
0.000 probe:submit_bio:(ffffffffac3aee00) bi_sector=7145704)
0.017 probe:submit_bio:(ffffffffac3aee00) bi_sector=7145712)
0.019 probe:submit_bio:(ffffffffac3aee00) bi_sector=7145720)
2.567 probe:submit_bio:(ffffffffac3aee00) bi_sector=7145728)
5631.919 probe:submit_bio:(ffffffffac3aee00) bi_sector=0)
5631.941 probe:submit_bio:(ffffffffac3aee00) bi_sector=8)
5631.945 probe:submit_bio:(ffffffffac3aee00) bi_sector=16)
5631.948 probe:submit_bio:(ffffffffac3aee00) bi_sector=24)
^C#
With callchains:
# trace --no-syscalls --ev probe:submit_bio/max-stack=10/
0.000 probe:submit_bio:(ffffffffac3aee00) bi_sector=50662544)
submit_bio+0xa8200001 ([kernel.kallsyms])
submit_bh+0xa8200013 ([kernel.kallsyms])
jbd2_journal_commit_transaction+0xa8200691 ([kernel.kallsyms])
kjournald2+0xa82000ca ([kernel.kallsyms])
kthread+0xa82000d8 ([kernel.kallsyms])
ret_from_fork+0xa820001f ([kernel.kallsyms])
0.023 probe:submit_bio:(ffffffffac3aee00) bi_sector=50662552)
submit_bio+0xa8200001 ([kernel.kallsyms])
submit_bh+0xa8200013 ([kernel.kallsyms])
jbd2_journal_commit_transaction+0xa8200691 ([kernel.kallsyms])
kjournald2+0xa82000ca ([kernel.kallsyms])
kthread+0xa82000d8 ([kernel.kallsyms])
ret_from_fork+0xa820001f ([kernel.kallsyms])
0.027 probe:submit_bio:(ffffffffac3aee00) bi_sector=50662560)
submit_bio+0xa8200001 ([kernel.kallsyms])
submit_bh+0xa8200013 ([kernel.kallsyms])
jbd2_journal_commit_transaction+0xa8200691 ([kernel.kallsyms])
kjournald2+0xa82000ca ([kernel.kallsyms])
kthread+0xa82000d8 ([kernel.kallsyms])
ret_from_fork+0xa820001f ([kernel.kallsyms])
2.593 probe:submit_bio:(ffffffffac3aee00) bi_sector=50662568)
submit_bio+0xa8200001 ([kernel.kallsyms])
submit_bh+0xa8200013 ([kernel.kallsyms])
journal_submit_commit_record+0xa82001ac ([kernel.kallsyms])
jbd2_journal_commit_transaction+0xa82012e8 ([kernel.kallsyms])
kjournald2+0xa82000ca ([kernel.kallsyms])
kthread+0xa82000d8 ([kernel.kallsyms])
ret_from_fork+0xa820001f ([kernel.kallsyms])
^C#
Signed-off-by: Naohiro Aota <naohiro.aota@hgst.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1470710408-23515-1-git-send-email-naohiro.aota@hgst.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The tools so far have been using the strerror_r() GNU variant, that
returns a string, be it the buffer passed or something else.
But that, besides being tricky in cases where we expect that the
function using strerror_r() returns the error formatted in a provided
buffer (we have to check if it returned something else and copy that
instead), breaks the build on systems not using glibc, like Alpine
Linux, where musl libc is used.
So, introduce yet another wrapper, str_error_r(), that has the GNU
interface, but uses the portable XSI variant of strerror_r(), so that
users rest asured that the provided buffer is used and it is what is
returned.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-d4t42fnf48ytlk8rjxs822tf@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Check the return value of strbuf APIs in perf-probe
related code, so that it can handle errors in strbuf.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20160510054707.6158.69861.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
We have addch() for chars, add() for fixed size data, and addstr() for
variable length strings, use them.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-0ap02fn2xtvpduj2j6b2o1j4@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
'perf probe' through debuginfo__find_probes() in util/probe-finder.c
checks for the functions' frame descriptions in either .eh_frame section
of an ELF or the .debug_frame.
The check is based on whether either one of these sections is present.
Depending on distro, toolchain defaults, architetcutre, build flags,
etc., CFI might be found in either .eh_frame and/or .debug_frame.
Sometimes, it may happen that, .eh_frame, even if present, may not be
complete and may miss some descriptions.
Therefore, to be sure, to find the CFI covering an address we will
always have to investigate both if available.
For e.g., in powerpc, this may happen:
$ gcc -g bin.c -o bin
$ objdump --dwarf ./bin
<1><145>: Abbrev Number: 7 (DW_TAG_subprogram)
<146> DW_AT_external : 1
<146> DW_AT_name : (indirect string, offset: 0x9e): main
<14a> DW_AT_decl_file : 1
<14b> DW_AT_decl_line : 39
<14c> DW_AT_prototyped : 1
<14c> DW_AT_type : <0x57>
<150> DW_AT_low_pc : 0x100007b8
If the .eh_frame and .debug_frame are checked for the same binary, we
will find that, .eh_frame (although present) doesn't contain a
description for "main" function.
But, .debug_frame has a description:
000000d8 00000024 00000000 FDE cie=00000000 pc=100007b8..10000838
DW_CFA_advance_loc: 16 to 100007c8
DW_CFA_def_cfa_offset: 144
DW_CFA_offset_extended_sf: r65 at cfa+16
...
Due to this (since, perf checks whether .eh_frame is present and goes on
searching for that address inside that frame), perf is unable to process
the probes:
# perf probe -x ./bin main
Failed to get call frame on 0x100007b8
Error: Failed to add events.
To avoid this issue, we need to check both the sections (.eh_frame and
.debug_frame), which is done in this patch.
Note that, we can always force everything into both .eh_frame and
.debug_frame by:
$ gcc bin.c -fasynchronous-unwind-tables -fno-dwarf2-cfi-asm -g -o bin
Signed-off-by: Hemant Kumar <hemant@linux.vnet.ibm.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Mark Wielaard <mjw@redhat.com>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1454426806-13974-1-git-send-email-hemant@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The commit 05c8d802fa ("perf probe: Fix to free temporal Dwarf_Frame")
tried to fix the memory leak of Dwarf_Frame, but it released the frame
at wrong point. Since the dwarf_frame_cfa(frame, &pf->fb_ops, &nops) can
return an address inside the frame data structure to pf->fb_ops, we can
not release the frame before using pf->fb_ops.
This reverts the commit and releases the frame afterwards (right before
returning from call_probe_finder) correctly.
Reported-and-Tested-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Reported-by: Michael Petlan <mpetlan@redhat.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: 05c8d802fa ("perf probe: Fix to free temporal Dwarf_Frame")
LPU-Reference: 20151125103432.1473.31009.stgit@localhost.localdomain
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Since dwarf_cfi_addrframe returns malloc'd Dwarf_Frame object, it has to
be freed after it is used.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20151118064011.30709.65674.stgit@localhost.localdomain
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When probing with a glob, errors in add_probe_trace_event() won't be
passed to debuginfo__find_trace_events() because it would be modified by
probe_point_search_cb(). It causes a segfault if perf fails to find an
argument for a probe point matched by the glob. For example:
# ./perf probe -v -n 'SyS_dup? oldfd'
probe-definition(0): SyS_dup? oldfd
symbol:SyS_dup? file:(null) line:0 offset:0 return:0 lazy:(null)
parsing arg: oldfd into oldfd
1 arguments
Looking at the vmlinux_path (7 entries long)
Using /lib/modules/4.3.0-rc4+/build/vmlinux for symbols
Open Debuginfo file: /lib/modules/4.3.0-rc4+/build/vmlinux
Try to find probe point from debuginfo.
Matched function: SyS_dup3
found inline addr: 0xffffffff812095c0
Probe point found: SyS_dup3+0
Searching 'oldfd' variable in context.
Converting variable oldfd into trace event.
oldfd type is long int.
found inline addr: 0xffffffff812096d4
Probe point found: SyS_dup2+36
Searching 'oldfd' variable in context.
Failed to find 'oldfd' in this function.
Matched function: SyS_dup3
Probe point found: SyS_dup3+0
Searching 'oldfd' variable in context.
Converting variable oldfd into trace event.
oldfd type is long int.
Matched function: SyS_dup2
Probe point found: SyS_dup2+0
Searching 'oldfd' variable in context.
Converting variable oldfd into trace event.
oldfd type is long int.
Found 4 probe_trace_events.
Opening /sys/kernel/debug/tracing//kprobe_events write=1
Writing event: p:probe/SyS_dup3 _text+2135488 oldfd=%di:s64
Segmentation fault (core dumped)
#
This patch ensures that add_probe_trace_event() doesn't touches
tf->ntevs and tf->tevs if those functions fail.
After the patch:
# perf probe 'SyS_dup? oldfd'
Failed to find 'oldfd' in this function.
Added new events:
probe:SyS_dup3 (on SyS_dup? with oldfd)
probe:SyS_dup3_1 (on SyS_dup? with oldfd)
probe:SyS_dup2 (on SyS_dup? with oldfd)
You can now use it in all perf tools, such as:
perf record -e probe:SyS_dup2 -aR sleep 1
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1447417761-156094-3-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Fix memory leaking on the debuginfo__find_trace_events() failure path
which frees an array of probe_trace_events but doesn't clears all the
allocated sub-structures and strings.
So, before doing zfree(tevs), clear all the array elements which may
have allocated resources.
Reported-by: Wang Nan <wangnan0@huawei.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1447417761-156094-2-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
perf probe shows more precisely message when it finds given
%return target function is inlined.
Without this fix:
----
# ./perf probe -V getname_flags%return
Return probe must be on the head of a real function.
Debuginfo analysis failed.
Error: Failed to show vars.
----
With this fix:
----
# ./perf probe -V getname_flags%return
Failed to find "getname_flags%return",
because getname_flags is an inlined function and has no return point.
Debuginfo analysis failed.
Error: Failed to show vars.
----
Suggested-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20150930164137.3733.55055.stgit@localhost.localdomain
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Perf probe always failed to find appropriate line numbers because of
failing to find .text start address offset from debuginfo.
e.g.
----
# ./perf probe -m pcspkr pcspkr_event:5
Added new events:
probe:pcspkr_event (on pcspkr_event:5 in pcspkr)
probe:pcspkr_event_1 (on pcspkr_event:5 in pcspkr)
You can now use it in all perf tools, such as:
perf record -e probe:pcspkr_event_1 -aR sleep 1
# ./perf probe -l
Failed to find debug information for address ffffffffa031f006
Failed to find debug information for address ffffffffa031f016
probe:pcspkr_event (on pcspkr_event+6 in pcspkr)
probe:pcspkr_event_1 (on pcspkr_event+22 in pcspkr)
----
This fixes the above issue as below.
1. Get the relative address of the symbol in .text by using
map->start.
2. Adjust the address by adding the offset of .text section
in the kernel module binary.
With this fix, perf probe -l shows lines correctly.
----
# ./perf probe -l
probe:pcspkr_event (on pcspkr_event:5@drivers/input/misc/pcspkr.c in pcspkr)
probe:pcspkr_event_1 (on pcspkr_event:5@drivers/input/misc/pcspkr.c in pcspkr)
----
Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20150930164132.3733.24643.stgit@localhost.localdomain
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Fix a trival bug about libdwfl usage of the report session, it should
explicitly begin and end a report session around dwfl_report_offline().
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20150930164128.3733.59876.stgit@localhost.localdomain
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
It should be useful to allow 'perf probe' probe at absolute offset of a
target. For example, when (u)probing at a instruction of a shared object
in a embedded system where debuginfo is not avaliable but we know the
offset of that instruction by manually digging.
This patch enables following perf probe command syntax:
# perf probe 0xffffffff811e6615
And
# perf probe /lib/x86_64-linux-gnu/libc-2.19.so 0xeb860
In the above example, we don't need a anchor symbol, so it is possible
to compute absolute addresses using other methods and then use 'perf
probe' to create the probing points.
v1 -> v2:
Drop the leading '+' in cmdline;
Allow uprobing at offset 0x0;
Improve 'perf probe -l' result when uprobe at area without debuginfo.
v2 -> v3:
Split bugfix to a separated patch.
Test result:
# perf probe 0xffffffff8119d175 %ax
# perf probe sys_write %ax
# perf probe /lib64/libc-2.18.so 0x0 %ax
# perf probe /lib64/libc-2.18.so 0x5 %ax
# perf probe /lib64/libc-2.18.so 0xd8e40 %ax
# perf probe /lib64/libc-2.18.so __write %ax
# perf probe /lib64/libc-2.18.so 0xd8e49 %ax
# cat /sys/kernel/debug/tracing/uprobe_events
p:probe_libc/abs_0 /lib64/libc-2.18.so:0x (null) arg1=%ax
p:probe_libc/abs_5 /lib64/libc-2.18.so:0x0000000000000005 arg1=%ax
p:probe_libc/abs_d8e40 /lib64/libc-2.18.so:0x00000000000d8e40 arg1=%ax
p:probe_libc/__write /lib64/libc-2.18.so:0x00000000000d8e40 arg1=%ax
p:probe_libc/abs_d8e49 /lib64/libc-2.18.so:0x00000000000d8e49 arg1=%ax
# cat /sys/kernel/debug/tracing/kprobe_events
p:probe/abs_ffffffff8119d175 0xffffffff8119d175 arg1=%ax
p:probe/sys_write _text+1692016 arg1=%ax
# perf probe -l
Failed to find debug information for address 5
probe:abs_ffffffff8119d175 (on sys_write+5 with arg1)
probe:sys_write (on sys_write with arg1)
probe_libc:__write (on @unix/syscall-template.S:81 in /lib64/libc-2.18.so with arg1)
probe_libc:abs_0 (on 0x0 in /lib64/libc-2.18.so with arg1)
probe_libc:abs_5 (on 0x5 in /lib64/libc-2.18.so with arg1)
probe_libc:abs_d8e40 (on @unix/syscall-template.S:81 in /lib64/libc-2.18.so with arg1)
probe_libc:abs_d8e49 (on __GI___libc_write+9 in /lib64/libc-2.18.so with arg1)
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1440586666-235233-7-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
So that we can pass more info to strlist__new() without having to change
its function signature, just adding entries to the strlist_config struct
with sensible defaults for when those fields are not specified.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-5uaaler4931i0s9sedxjquhq@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This has a different model than the 'thread' and 'map' struct lifetimes:
there is not a definitive "don't use this DSO anymore" event, i.e. we may
get many 'struct map' holding references to the '/usr/lib64/libc-2.20.so'
DSO but then at some point some DSO may have no references but we still
don't want to straight away release its resources, because "soon" we may
get a new 'struct map' that needs it and we want to reuse its symtab or
other resources.
So we need some way to garbage collect it when crossing some memory
usage threshold, which is left for anoter patch, for now it is
sufficient to release it when calling dsos__exit(), i.e. when deleting
the whole list as part of deleting the 'struct machine' containing it,
which will leave only referenced objects being used.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/n/tip-majzgz07cm90t2tejrjy4clf@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
perf probe currently errors out if there are any tail calls to probed
functions:
[root@rhel71be]# perf probe do_fork
Failed to find probe point in any functions.
Error: Failed to add events.
Fix this by teaching perf to ignore tail calls.
Without patch:
[root@rhel71be perf]# ./perf probe -v do_fork
probe-definition(0): do_fork symbol:do_fork file:(null) line:0 offset:0
return:0 lazy:(null)
0 arguments
Looking at the vmlinux_path (7 entries long)
symsrc__init: build id mismatch for /boot/vmlinux.
Using /usr/lib/debug/lib/modules/3.10.0-201.el7.ppc64/vmlinux for symbols
Open Debuginfo file:
/usr/lib/debug/lib/modules/3.10.0-201.el7.ppc64/vmlinux
Try to find probe point from debuginfo.
found inline addr: 0xc0000000000bb9b0
Probe point found: do_fork+0
found inline addr: 0xc0000000000bbe20
Probe point found: kernel_thread+48
found inline addr: 0xc0000000000bbe5c
Probe point found: sys_fork+28
found inline addr: 0xc0000000000bbfac
Probe point found: sys_vfork+44
found inline addr: 0xc0000000000bc27c
Failed to find probe point in any functions.
An error occurred in debuginfo analysis (-2).
Error: Failed to add events. Reason: No such file or directory (Code: -2)
With patch:
[root@rhel71be perf]# ./perf probe -v do_fork
probe-definition(0): do_fork symbol:do_fork file:(null) line:0 offset:0
return:0 lazy:(null)
0 arguments
Looking at the vmlinux_path (7 entries long)
symsrc__init: build id mismatch for /boot/vmlinux.
Using /usr/lib/debug/lib/modules/3.10.0-201.el7.ppc64/vmlinux for symbols
Open Debuginfo file:
/usr/lib/debug/lib/modules/3.10.0-201.el7.ppc64/vmlinux
Try to find probe point from debuginfo.
found inline addr: 0xc0000000000bb9b0
Probe point found: do_fork+0
found inline addr: 0xc0000000000bbe20
Probe point found: kernel_thread+48
found inline addr: 0xc0000000000bbe5c
Probe point found: sys_fork+28
found inline addr: 0xc0000000000bbfac
Probe point found: sys_vfork+44
found inline addr: 0xc0000000000bc27c
Ignoring tail call from SyS_clone
Found 4 probe_trace_events.
Opening /sys/kernel/debug/tracing/kprobe_events write=1
No kprobe blacklist support, ignored
Added new events:
Writing event: p:probe/do_fork _text+768432
Failed to write event: Invalid argument
Error: Failed to add events. Reason: Invalid argument (Code: -22)
[Ignore the error about failure to write event - this kernel is missing
a patch to resolve _text properly]
The reason to ignore tail calls is that the address does not belong to
any function frame. In the example above, the address in SyS_clone is
0xc0000000000bc27c, but looking at the debug-info:
<1><830081>: Abbrev Number: 133 (DW_TAG_subprogram)
<830083> DW_AT_external : 1
<830083> DW_AT_name : (indirect string, offset: 0x3cea3): SyS_clone
<830087> DW_AT_decl_file : 7
<830088> DW_AT_decl_line : 1689
<83008a> DW_AT_prototyped : 1
<83008a> DW_AT_type : <0x8110eb>
<83008e> DW_AT_low_pc : 0xc0000000000bc270
<830096> DW_AT_high_pc : 0xc
<83009e> DW_AT_frame_base : 1 byte block: 9c (DW_OP_call_frame_cfa)
<8300a0> DW_AT_GNU_all_call_sites: 1
<8300a0> DW_AT_sibling : <0x830178>
<snip>
<3><830147>: Abbrev Number: 125 (DW_TAG_GNU_call_site)
<830148> DW_AT_low_pc : 0xc0000000000bc27c
<830150> DW_AT_GNU_tail_call: 1
<830150> DW_AT_abstract_origin: <0x82e7e1>
The frame ends at 0xc0000000000bc27c. I suppose this is why this
particular call is a "tail" call. FWIW, systemtap seems to ignore these
as well and requires users to explicitly place probes at these call
sites if necessary. I print out the caller so that users know.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Link: http://lkml.kernel.org/r/1430394151-15928-1-git-send-email-naveen.n.rao@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Thomas Richter