Revision tags: v6.6.25, v6.6.24, v6.6.23, v6.6.16, v6.6.15, v6.6.14, v6.6.13, v6.6.12, v6.6.11, v6.6.10, v6.6.9, v6.6.8 |
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#
d9a6029d |
| 13-Dec-2023 |
Zheng Yejian <zhengyejian1@huawei.com> |
tracing: Fix uaf issue when open the hist or hist_debug file
[ Upstream commit 1cc111b9cddc71ce161cd388f11f0e9048edffdb ]
KASAN report following issue. The root cause is when opening 'hist' file of
tracing: Fix uaf issue when open the hist or hist_debug file
[ Upstream commit 1cc111b9cddc71ce161cd388f11f0e9048edffdb ]
KASAN report following issue. The root cause is when opening 'hist' file of an instance and accessing 'trace_event_file' in hist_show(), but 'trace_event_file' has been freed due to the instance being removed. 'hist_debug' file has the same problem. To fix it, call tracing_{open,release}_file_tr() in file_operations callback to have the ref count and avoid 'trace_event_file' being freed.
BUG: KASAN: slab-use-after-free in hist_show+0x11e0/0x1278 Read of size 8 at addr ffff242541e336b8 by task head/190
CPU: 4 PID: 190 Comm: head Not tainted 6.7.0-rc5-g26aff849438c #133 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0x98/0xf8 show_stack+0x1c/0x30 dump_stack_lvl+0x44/0x58 print_report+0xf0/0x5a0 kasan_report+0x80/0xc0 __asan_report_load8_noabort+0x1c/0x28 hist_show+0x11e0/0x1278 seq_read_iter+0x344/0xd78 seq_read+0x128/0x1c0 vfs_read+0x198/0x6c8 ksys_read+0xf4/0x1e0 __arm64_sys_read+0x70/0xa8 invoke_syscall+0x70/0x260 el0_svc_common.constprop.0+0xb0/0x280 do_el0_svc+0x44/0x60 el0_svc+0x34/0x68 el0t_64_sync_handler+0xb8/0xc0 el0t_64_sync+0x168/0x170
Allocated by task 188: kasan_save_stack+0x28/0x50 kasan_set_track+0x28/0x38 kasan_save_alloc_info+0x20/0x30 __kasan_slab_alloc+0x6c/0x80 kmem_cache_alloc+0x15c/0x4a8 trace_create_new_event+0x84/0x348 __trace_add_new_event+0x18/0x88 event_trace_add_tracer+0xc4/0x1a0 trace_array_create_dir+0x6c/0x100 trace_array_create+0x2e8/0x568 instance_mkdir+0x48/0x80 tracefs_syscall_mkdir+0x90/0xe8 vfs_mkdir+0x3c4/0x610 do_mkdirat+0x144/0x200 __arm64_sys_mkdirat+0x8c/0xc0 invoke_syscall+0x70/0x260 el0_svc_common.constprop.0+0xb0/0x280 do_el0_svc+0x44/0x60 el0_svc+0x34/0x68 el0t_64_sync_handler+0xb8/0xc0 el0t_64_sync+0x168/0x170
Freed by task 191: kasan_save_stack+0x28/0x50 kasan_set_track+0x28/0x38 kasan_save_free_info+0x34/0x58 __kasan_slab_free+0xe4/0x158 kmem_cache_free+0x19c/0x508 event_file_put+0xa0/0x120 remove_event_file_dir+0x180/0x320 event_trace_del_tracer+0xb0/0x180 __remove_instance+0x224/0x508 instance_rmdir+0x44/0x78 tracefs_syscall_rmdir+0xbc/0x140 vfs_rmdir+0x1cc/0x4c8 do_rmdir+0x220/0x2b8 __arm64_sys_unlinkat+0xc0/0x100 invoke_syscall+0x70/0x260 el0_svc_common.constprop.0+0xb0/0x280 do_el0_svc+0x44/0x60 el0_svc+0x34/0x68 el0t_64_sync_handler+0xb8/0xc0 el0t_64_sync+0x168/0x170
Link: https://lore.kernel.org/linux-trace-kernel/20231214012153.676155-1-zhengyejian1@huawei.com
Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
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Revision tags: v6.6.7, v6.6.6, v6.6.5, v6.6.4, v6.6.3, v6.6.2, v6.5.11, v6.6.1, v6.5.10, v6.6, v6.5.9, v6.5.8, v6.5.7, v6.5.6, v6.5.5, v6.5.4, v6.5.3, v6.5.2, v6.1.51, v6.5.1, v6.1.50, v6.5, v6.1.49, v6.1.48, v6.1.46, v6.1.45, v6.1.44, v6.1.43, v6.1.42, v6.1.41, v6.1.40, v6.1.39 |
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#
4b8b3905 |
| 14-Jul-2023 |
Mohamed Khalfella <mkhalfella@purestorage.com> |
tracing/histograms: Return an error if we fail to add histogram to hist_vars list
Commit 6018b585e8c6 ("tracing/histograms: Add histograms to hist_vars if they have referenced variables") added a ch
tracing/histograms: Return an error if we fail to add histogram to hist_vars list
Commit 6018b585e8c6 ("tracing/histograms: Add histograms to hist_vars if they have referenced variables") added a check to fail histogram creation if save_hist_vars() failed to add histogram to hist_vars list. But the commit failed to set ret to failed return code before jumping to unregister histogram, fix it.
Link: https://lore.kernel.org/linux-trace-kernel/20230714203341.51396-1-mkhalfella@purestorage.com
Cc: stable@vger.kernel.org Fixes: 6018b585e8c6 ("tracing/histograms: Add histograms to hist_vars if they have referenced variables") Signed-off-by: Mohamed Khalfella <mkhalfella@purestorage.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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6018b585 |
| 12-Jul-2023 |
Mohamed Khalfella <mkhalfella@purestorage.com> |
tracing/histograms: Add histograms to hist_vars if they have referenced variables
Hist triggers can have referenced variables without having direct variables fields. This can be the case if referenc
tracing/histograms: Add histograms to hist_vars if they have referenced variables
Hist triggers can have referenced variables without having direct variables fields. This can be the case if referenced variables are added for trigger actions. In this case the newly added references will not have field variables. Not taking such referenced variables into consideration can result in a bug where it would be possible to remove hist trigger with variables being refenced. This will result in a bug that is easily reproducable like so
$ cd /sys/kernel/tracing $ echo 'synthetic_sys_enter char[] comm; long id' >> synthetic_events $ echo 'hist:keys=common_pid.execname,id.syscall:vals=hitcount:comm=common_pid.execname' >> events/raw_syscalls/sys_enter/trigger $ echo 'hist:keys=common_pid.execname,id.syscall:onmatch(raw_syscalls.sys_enter).synthetic_sys_enter($comm, id)' >> events/raw_syscalls/sys_enter/trigger $ echo '!hist:keys=common_pid.execname,id.syscall:vals=hitcount:comm=common_pid.execname' >> events/raw_syscalls/sys_enter/trigger
[ 100.263533] ================================================================== [ 100.264634] BUG: KASAN: slab-use-after-free in resolve_var_refs+0xc7/0x180 [ 100.265520] Read of size 8 at addr ffff88810375d0f0 by task bash/439 [ 100.266320] [ 100.266533] CPU: 2 PID: 439 Comm: bash Not tainted 6.5.0-rc1 #4 [ 100.267277] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-20220807_005459-localhost 04/01/2014 [ 100.268561] Call Trace: [ 100.268902] <TASK> [ 100.269189] dump_stack_lvl+0x4c/0x70 [ 100.269680] print_report+0xc5/0x600 [ 100.270165] ? resolve_var_refs+0xc7/0x180 [ 100.270697] ? kasan_complete_mode_report_info+0x80/0x1f0 [ 100.271389] ? resolve_var_refs+0xc7/0x180 [ 100.271913] kasan_report+0xbd/0x100 [ 100.272380] ? resolve_var_refs+0xc7/0x180 [ 100.272920] __asan_load8+0x71/0xa0 [ 100.273377] resolve_var_refs+0xc7/0x180 [ 100.273888] event_hist_trigger+0x749/0x860 [ 100.274505] ? kasan_save_stack+0x2a/0x50 [ 100.275024] ? kasan_set_track+0x29/0x40 [ 100.275536] ? __pfx_event_hist_trigger+0x10/0x10 [ 100.276138] ? ksys_write+0xd1/0x170 [ 100.276607] ? do_syscall_64+0x3c/0x90 [ 100.277099] ? entry_SYSCALL_64_after_hwframe+0x6e/0xd8 [ 100.277771] ? destroy_hist_data+0x446/0x470 [ 100.278324] ? event_hist_trigger_parse+0xa6c/0x3860 [ 100.278962] ? __pfx_event_hist_trigger_parse+0x10/0x10 [ 100.279627] ? __kasan_check_write+0x18/0x20 [ 100.280177] ? mutex_unlock+0x85/0xd0 [ 100.280660] ? __pfx_mutex_unlock+0x10/0x10 [ 100.281200] ? kfree+0x7b/0x120 [ 100.281619] ? ____kasan_slab_free+0x15d/0x1d0 [ 100.282197] ? event_trigger_write+0xac/0x100 [ 100.282764] ? __kasan_slab_free+0x16/0x20 [ 100.283293] ? __kmem_cache_free+0x153/0x2f0 [ 100.283844] ? sched_mm_cid_remote_clear+0xb1/0x250 [ 100.284550] ? __pfx_sched_mm_cid_remote_clear+0x10/0x10 [ 100.285221] ? event_trigger_write+0xbc/0x100 [ 100.285781] ? __kasan_check_read+0x15/0x20 [ 100.286321] ? __bitmap_weight+0x66/0xa0 [ 100.286833] ? _find_next_bit+0x46/0xe0 [ 100.287334] ? task_mm_cid_work+0x37f/0x450 [ 100.287872] event_triggers_call+0x84/0x150 [ 100.288408] trace_event_buffer_commit+0x339/0x430 [ 100.289073] ? ring_buffer_event_data+0x3f/0x60 [ 100.292189] trace_event_raw_event_sys_enter+0x8b/0xe0 [ 100.295434] syscall_trace_enter.constprop.0+0x18f/0x1b0 [ 100.298653] syscall_enter_from_user_mode+0x32/0x40 [ 100.301808] do_syscall_64+0x1a/0x90 [ 100.304748] entry_SYSCALL_64_after_hwframe+0x6e/0xd8 [ 100.307775] RIP: 0033:0x7f686c75c1cb [ 100.310617] Code: 73 01 c3 48 8b 0d 65 3c 10 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 21 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 35 3c 10 00 f7 d8 64 89 01 48 [ 100.317847] RSP: 002b:00007ffc60137a38 EFLAGS: 00000246 ORIG_RAX: 0000000000000021 [ 100.321200] RAX: ffffffffffffffda RBX: 000055f566469ea0 RCX: 00007f686c75c1cb [ 100.324631] RDX: 0000000000000001 RSI: 0000000000000001 RDI: 000000000000000a [ 100.328104] RBP: 00007ffc60137ac0 R08: 00007f686c818460 R09: 000000000000000a [ 100.331509] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000009 [ 100.334992] R13: 0000000000000007 R14: 000000000000000a R15: 0000000000000007 [ 100.338381] </TASK>
We hit the bug because when second hist trigger has was created has_hist_vars() returned false because hist trigger did not have variables. As a result of that save_hist_vars() was not called to add the trigger to trace_array->hist_vars. Later on when we attempted to remove the first histogram find_any_var_ref() failed to detect it is being used because it did not find the second trigger in hist_vars list.
With this change we wait until trigger actions are created so we can take into consideration if hist trigger has variable references. Also, now we check the return value of save_hist_vars() and fail trigger creation if save_hist_vars() fails.
Link: https://lore.kernel.org/linux-trace-kernel/20230712223021.636335-1-mkhalfella@purestorage.com
Cc: stable@vger.kernel.org Fixes: 067fe038e70f6 ("tracing: Add variable reference handling to hist triggers") Signed-off-by: Mohamed Khalfella <mkhalfella@purestorage.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Revision tags: v6.1.38, v6.1.37, v6.1.36, v6.4, v6.1.35, v6.1.34, v6.1.33, v6.1.32, v6.1.31, v6.1.30 |
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#
4b512860 |
| 23-May-2023 |
Steven Rostedt (Google) <rostedt@goodmis.org> |
tracing: Rename stacktrace field to common_stacktrace
The histogram and synthetic events can use a pseudo event called "stacktrace" that will create a stacktrace at the time of the event and use it
tracing: Rename stacktrace field to common_stacktrace
The histogram and synthetic events can use a pseudo event called "stacktrace" that will create a stacktrace at the time of the event and use it just like it was a normal field. We have other pseudo events such as "common_cpu" and "common_timestamp". To stay consistent with that, convert "stacktrace" to "common_stacktrace". As this was used in older kernels, to keep backward compatibility, this will act just like "common_cpu" did with "cpu". That is, "cpu" will be the same as "common_cpu" unless the event has a "cpu" field. In which case, the event's field is used. The same is true with "stacktrace".
Also update the documentation to reflect this change.
Link: https://lore.kernel.org/linux-trace-kernel/20230523230913.6860e28d@rorschach.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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#
e30fbc61 |
| 23-May-2023 |
Steven Rostedt (Google) <rostedt@goodmis.org> |
tracing/histograms: Allow variables to have some modifiers
Modifiers are used to change the behavior of keys. For instance, they can grouped into buckets, converted to syscall names (from the syscal
tracing/histograms: Allow variables to have some modifiers
Modifiers are used to change the behavior of keys. For instance, they can grouped into buckets, converted to syscall names (from the syscall identifier), show task->comm of the current pid, be an array of longs that represent a stacktrace, and more.
It was found that nothing stopped a value from taking a modifier. As values are simple counters. If this happened, it would call code that was not expecting a modifier and crash the kernel. This was fixed by having the ___create_val_field() function test if a modifier was present and fail if one was. This fixed the crash.
Now there's a problem with variables. Variables are used to pass fields from one event to another. Variables are allowed to have some modifiers, as the processing may need to happen at the time of the event (like stacktraces and comm names of the current pid). The issue is that it too uses __create_val_field(). Now that fails on modifiers, variables can no longer use them (this is a regression).
As not all modifiers are for variables, have them use a separate check.
Link: https://lore.kernel.org/linux-trace-kernel/20230523221108.064a5d82@rorschach.local.home
Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Fixes: e0213434fe3e4 ("tracing: Do not let histogram values have some modifiers") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Revision tags: v6.1.29, v6.1.28, v6.1.27, v6.1.26, v6.3, v6.1.25, v6.1.24, v6.1.23, v6.1.22, v6.1.21, v6.1.20, v6.1.19, v6.1.18, v6.1.17, v6.1.16, v6.1.15 |
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#
9f116f76 |
| 01-Mar-2023 |
Steven Rostedt (Google) <rostedt@goodmis.org> |
tracing: Check field value in hist_field_name()
The function hist_field_name() cannot handle being passed a NULL field parameter. It should never be NULL, but due to a previous bug, NULL was passed
tracing: Check field value in hist_field_name()
The function hist_field_name() cannot handle being passed a NULL field parameter. It should never be NULL, but due to a previous bug, NULL was passed to the function and the kernel crashed due to a NULL dereference. Mark Rutland reported this to me on IRC.
The bug was fixed, but to prevent future bugs from crashing the kernel, check the field and add a WARN_ON() if it is NULL.
Link: https://lkml.kernel.org/r/20230302020810.762384440@goodmis.org
Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Reported-by: Mark Rutland <mark.rutland@arm.com> Fixes: c6afad49d127f ("tracing: Add hist trigger 'sym' and 'sym-offset' modifiers") Tested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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#
e0213434 |
| 01-Mar-2023 |
Steven Rostedt (Google) <rostedt@goodmis.org> |
tracing: Do not let histogram values have some modifiers
Histogram values can not be strings, stacktraces, graphs, symbols, syscalls, or grouped in buckets or log. Give an error if a value is set to
tracing: Do not let histogram values have some modifiers
Histogram values can not be strings, stacktraces, graphs, symbols, syscalls, or grouped in buckets or log. Give an error if a value is set to do so.
Note, the histogram code was not prepared to handle these modifiers for histograms and caused a bug.
Mark Rutland reported:
# echo 'p:copy_to_user __arch_copy_to_user n=$arg2' >> /sys/kernel/tracing/kprobe_events # echo 'hist:keys=n:vals=hitcount.buckets=8:sort=hitcount' > /sys/kernel/tracing/events/kprobes/copy_to_user/trigger # cat /sys/kernel/tracing/events/kprobes/copy_to_user/hist [ 143.694628] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [ 143.695190] Mem abort info: [ 143.695362] ESR = 0x0000000096000004 [ 143.695604] EC = 0x25: DABT (current EL), IL = 32 bits [ 143.695889] SET = 0, FnV = 0 [ 143.696077] EA = 0, S1PTW = 0 [ 143.696302] FSC = 0x04: level 0 translation fault [ 143.702381] Data abort info: [ 143.702614] ISV = 0, ISS = 0x00000004 [ 143.702832] CM = 0, WnR = 0 [ 143.703087] user pgtable: 4k pages, 48-bit VAs, pgdp=00000000448f9000 [ 143.703407] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 [ 143.704137] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP [ 143.704714] Modules linked in: [ 143.705273] CPU: 0 PID: 133 Comm: cat Not tainted 6.2.0-00003-g6fc512c10a7c #3 [ 143.706138] Hardware name: linux,dummy-virt (DT) [ 143.706723] pstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 143.707120] pc : hist_field_name.part.0+0x14/0x140 [ 143.707504] lr : hist_field_name.part.0+0x104/0x140 [ 143.707774] sp : ffff800008333a30 [ 143.707952] x29: ffff800008333a30 x28: 0000000000000001 x27: 0000000000400cc0 [ 143.708429] x26: ffffd7a653b20260 x25: 0000000000000000 x24: ffff10d303ee5800 [ 143.708776] x23: ffffd7a6539b27b0 x22: ffff10d303fb8c00 x21: 0000000000000001 [ 143.709127] x20: ffff10d303ec2000 x19: 0000000000000000 x18: 0000000000000000 [ 143.709478] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 [ 143.709824] x14: 0000000000000000 x13: 203a6f666e692072 x12: 6567676972742023 [ 143.710179] x11: 0a230a6d6172676f x10: 000000000000002c x9 : ffffd7a6521e018c [ 143.710584] x8 : 000000000000002c x7 : 7f7f7f7f7f7f7f7f x6 : 000000000000002c [ 143.710915] x5 : ffff10d303b0103e x4 : ffffd7a653b20261 x3 : 000000000000003d [ 143.711239] x2 : 0000000000020001 x1 : 0000000000000001 x0 : 0000000000000000 [ 143.711746] Call trace: [ 143.712115] hist_field_name.part.0+0x14/0x140 [ 143.712642] hist_field_name.part.0+0x104/0x140 [ 143.712925] hist_field_print+0x28/0x140 [ 143.713125] event_hist_trigger_print+0x174/0x4d0 [ 143.713348] hist_show+0xf8/0x980 [ 143.713521] seq_read_iter+0x1bc/0x4b0 [ 143.713711] seq_read+0x8c/0xc4 [ 143.713876] vfs_read+0xc8/0x2a4 [ 143.714043] ksys_read+0x70/0xfc [ 143.714218] __arm64_sys_read+0x24/0x30 [ 143.714400] invoke_syscall+0x50/0x120 [ 143.714587] el0_svc_common.constprop.0+0x4c/0x100 [ 143.714807] do_el0_svc+0x44/0xd0 [ 143.714970] el0_svc+0x2c/0x84 [ 143.715134] el0t_64_sync_handler+0xbc/0x140 [ 143.715334] el0t_64_sync+0x190/0x194 [ 143.715742] Code: a9bd7bfd 910003fd a90153f3 aa0003f3 (f9400000) [ 143.716510] ---[ end trace 0000000000000000 ]--- Segmentation fault
Link: https://lkml.kernel.org/r/20230302020810.559462599@goodmis.org
Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Fixes: c6afad49d127f ("tracing: Add hist trigger 'sym' and 'sym-offset' modifiers") Reported-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Revision tags: v6.1.14, v6.1.13, v6.2, v6.1.12 |
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#
f5914b30 |
| 10-Feb-2023 |
Tom Zanussi <zanussi@kernel.org> |
tracing/histogram: Fix stacktrace key
The current code will always use the current stacktrace as a key even if a stacktrace contained in a specific event field was specified.
For example, we expect
tracing/histogram: Fix stacktrace key
The current code will always use the current stacktrace as a key even if a stacktrace contained in a specific event field was specified.
For example, we expect to use the 'unsigned long[] stack' field in the below event in the histogram:
# echo 's:block_lat pid_t pid; u64 delta; unsigned long[] stack;' > /sys/kernel/debug/tracing/dynamic_events # echo 'hist:keys=delta.buckets=100,stack.stacktrace:sort=delta' > /sys/kernel/debug/tracing/events/synthetic/block_lat/trigger
But in fact, when we type out the trigger, we see that it's using the plain old global 'stacktrace' as the key, which is just the stacktrace when the event was hit and not the stacktrace contained in the event, which is what we want:
# cat /sys/kernel/debug/tracing/events/synthetic/block_lat/trigger hist:keys=delta.buckets=100,stacktrace:vals=hitcount:sort=delta.buckets=100:size=2048 [active]
And in fact, there's no code to actually retrieve it from the event, so we need to add HIST_FIELD_FN_STACK and hist_field_stack() to get it and hook it into the trigger code. For now, since the stack is just using dynamic strings, this could just use the dynamic string function, but it seems cleaner to have a dedicated function an be able to tweak independently as necessary.
Link: https://lkml.kernel.org/r/11aa614c82976adbfa4ea763dbe885b5fb01d59c.1676063532.git.zanussi@kernel.org
Signed-off-by: Tom Zanussi <zanussi@kernel.org> [ Fixed 32bit build warning reported by kernel test robot <lkp@intel.com> ] Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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#
2bacfd9f |
| 10-Feb-2023 |
Tom Zanussi <zanussi@kernel.org> |
tracing/histogram: Fix a few problems with stacktrace variable printing
Currently, there are a few problems when printing hist triggers and trace output when using stacktrace variables. This fixes
tracing/histogram: Fix a few problems with stacktrace variable printing
Currently, there are a few problems when printing hist triggers and trace output when using stacktrace variables. This fixes the problems seen below:
# echo 'hist:keys=delta.buckets=100,stack.stacktrace:sort=delta' > /sys/kernel/debug/tracing/events/synthetic/block_lat/trigger # cat /sys/kernel/debug/tracing/events/synthetic/block_lat/trigger hist:keys=delta.buckets=100,stacktrace:vals=hitcount:sort=delta.buckets=100:size=2048 [active]
# echo 'hist:keys=next_pid:ts=common_timestamp.usecs,st=stacktrace if prev_state == 2' >> /sys/kernel/debug/tracing/events/sched/sched_switch/trigger # cat /sys/kernel/debug/tracing/events/sched/sched_switch/trigger hist:keys=next_pid:vals=hitcount:ts=common_timestamp.usecs,st=stacktrace.stacktrace:sort=hitcount:size=2048:clock=global if prev_state == 2 [active]
and also in the trace output (should be stack.stacktrace):
{ delta: ~ 100-199, stacktrace __schedule+0xa19/0x1520
Link: https://lkml.kernel.org/r/60bebd4e546728e012a7a2bcbf58716d48ba6edb.1676063532.git.zanussi@kernel.org
Signed-off-by: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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#
8261ef2e |
| 15-Feb-2023 |
Steven Rostedt (Google) <rostedt@goodmis.org> |
tracing: Add BUILD_BUG() to make sure stacktrace fits in strings
The max string length for a histogram variable is 256 bytes. The max depth of a stacktrace is 16. With 8byte words, that's 16 * 8 = 1
tracing: Add BUILD_BUG() to make sure stacktrace fits in strings
The max string length for a histogram variable is 256 bytes. The max depth of a stacktrace is 16. With 8byte words, that's 16 * 8 = 128. Which can easily fit in the string variable. The histogram stacktrace is being stored in the string value (with the given max length), with the assumption it will fit. To make sure that this is always the case (in the case that the stack trace depth increases), add a BUILD_BUG_ON() to test this.
Link: https://lore.kernel.org/linux-trace-kernel/20230214002418.0103b9e765d3e5c374d2aa7d@kernel.org/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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#
fc1a9dc1 |
| 10-Feb-2023 |
Tom Zanussi <zanussi@kernel.org> |
tracing/histogram: Don't use strlen to find length of stacktrace variables
Because stacktraces are saved in dynamic strings, trace_event_raw_event_synth() uses strlen to determine the length of the
tracing/histogram: Don't use strlen to find length of stacktrace variables
Because stacktraces are saved in dynamic strings, trace_event_raw_event_synth() uses strlen to determine the length of the stack. Stacktraces may contain 0-bytes, though, in the saved addresses, so the length found and passed to reserve() will be too small.
Fix this by using the first unsigned long in the stack variables to store the actual number of elements in the stack and have trace_event_raw_event_synth() use that to determine the length of the stack.
Link: https://lkml.kernel.org/r/1ed6906cd9d6477ef2bd8e63c61de20a9ffe64d7.1676063532.git.zanussi@kernel.org
Signed-off-by: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Revision tags: v6.1.11, v6.1.10, v6.1.9, v6.1.8, v6.1.7 |
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#
cc5fc8bf |
| 17-Jan-2023 |
Steven Rostedt (Google) <rostedt@goodmis.org> |
tracing/histogram: Add stacktrace type
Now that stacktraces can be part of synthetic events, allow a key to be typed as a stacktrace.
# cd /sys/kernel/tracing # echo 's:block_lat u64 delta; uns
tracing/histogram: Add stacktrace type
Now that stacktraces can be part of synthetic events, allow a key to be typed as a stacktrace.
# cd /sys/kernel/tracing # echo 's:block_lat u64 delta; unsigned long stack[];' >> dynamic_events # echo 'hist:keys=next_pid:ts=common_timestamp.usecs,st=stacktrace if prev_state == 2' >> events/sched/sched_switch/trigger # echo 'hist:keys=prev_pid:delta=common_timestamp.usecs-$ts,st2=$st:onmatch(sched.sched_switch).trace(block_lat,$delta,$st2)' >> events/sched/sched_switch/trigger # echo 'hist:keys=delta.buckets=100,stack.stacktrace:sort=delta' > events/synthetic/block_lat/trigger
# cat events/synthetic/block_lat/hist
# event histogram # # trigger info: hist:keys=delta.buckets=100,stacktrace:vals=hitcount:sort=delta.buckets=100:size=2048 [active] #
{ delta: ~ 0-99, stacktrace: event_hist_trigger+0x464/0x480 event_triggers_call+0x52/0xe0 trace_event_buffer_commit+0x193/0x250 trace_event_raw_event_sched_switch+0xfc/0x150 __traceiter_sched_switch+0x41/0x60 __schedule+0x448/0x7b0 schedule_idle+0x26/0x40 cpu_startup_entry+0x19/0x20 start_secondary+0xed/0xf0 secondary_startup_64_no_verify+0xe0/0xeb } hitcount: 6 { delta: ~ 0-99, stacktrace: event_hist_trigger+0x464/0x480 event_triggers_call+0x52/0xe0 trace_event_buffer_commit+0x193/0x250 trace_event_raw_event_sched_switch+0xfc/0x150 __traceiter_sched_switch+0x41/0x60 __schedule+0x448/0x7b0 schedule_idle+0x26/0x40 cpu_startup_entry+0x19/0x20 __pfx_kernel_init+0x0/0x10 arch_call_rest_init+0xa/0x24 start_kernel+0x964/0x98d secondary_startup_64_no_verify+0xe0/0xeb } hitcount: 3 { delta: ~ 0-99, stacktrace: event_hist_trigger+0x464/0x480 event_triggers_call+0x52/0xe0 trace_event_buffer_commit+0x193/0x250 trace_event_raw_event_sched_switch+0xfc/0x150 __traceiter_sched_switch+0x41/0x60 __schedule+0x448/0x7b0 schedule+0x5a/0xb0 worker_thread+0xaf/0x380 kthread+0xe9/0x110 ret_from_fork+0x2c/0x50 } hitcount: 1 { delta: ~ 100-199, stacktrace: event_hist_trigger+0x464/0x480 event_triggers_call+0x52/0xe0 trace_event_buffer_commit+0x193/0x250 trace_event_raw_event_sched_switch+0xfc/0x150 __traceiter_sched_switch+0x41/0x60 __schedule+0x448/0x7b0 schedule_idle+0x26/0x40 cpu_startup_entry+0x19/0x20 start_secondary+0xed/0xf0 secondary_startup_64_no_verify+0xe0/0xeb } hitcount: 15 [..] { delta: ~ 8500-8599, stacktrace: event_hist_trigger+0x464/0x480 event_triggers_call+0x52/0xe0 trace_event_buffer_commit+0x193/0x250 trace_event_raw_event_sched_switch+0xfc/0x150 __traceiter_sched_switch+0x41/0x60 __schedule+0x448/0x7b0 schedule_idle+0x26/0x40 cpu_startup_entry+0x19/0x20 start_secondary+0xed/0xf0 secondary_startup_64_no_verify+0xe0/0xeb } hitcount: 1
Totals: Hits: 89 Entries: 11 Dropped: 0
Link: https://lkml.kernel.org/r/20230117152236.167046397@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Ross Zwisler <zwisler@google.com> Cc: Ching-lin Yu <chinglinyu@google.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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#
00cf3d67 |
| 17-Jan-2023 |
Steven Rostedt (Google) <rostedt@goodmis.org> |
tracing: Allow synthetic events to pass around stacktraces
Allow a stacktrace from one event to be displayed by the end event of a synthetic event. This is very useful when looking for the longest l
tracing: Allow synthetic events to pass around stacktraces
Allow a stacktrace from one event to be displayed by the end event of a synthetic event. This is very useful when looking for the longest latency of a sleep or something blocked on I/O.
# cd /sys/kernel/tracing/ # echo 's:block_lat pid_t pid; u64 delta; unsigned long[] stack;' > dynamic_events # echo 'hist:keys=next_pid:ts=common_timestamp.usecs,st=stacktrace if prev_state == 1||prev_state == 2' > events/sched/sched_switch/trigger # echo 'hist:keys=prev_pid:delta=common_timestamp.usecs-$ts,s=$st:onmax($delta).trace(block_lat,prev_pid,$delta,$s)' >> events/sched/sched_switch/trigger
The above creates a "block_lat" synthetic event that take the stacktrace of when a task schedules out in either the interruptible or uninterruptible states, and on a new per process max $delta (the time it was scheduled out), will print the process id and the stacktrace.
# echo 1 > events/synthetic/block_lat/enable # cat trace # TASK-PID CPU# ||||| TIMESTAMP FUNCTION # | | | ||||| | | kworker/u16:0-767 [006] d..4. 560.645045: block_lat: pid=767 delta=66 stack=STACK: => __schedule => schedule => pipe_read => vfs_read => ksys_read => do_syscall_64 => 0x966000aa
<idle>-0 [003] d..4. 561.132117: block_lat: pid=0 delta=413787 stack=STACK: => __schedule => schedule => schedule_hrtimeout_range_clock => do_sys_poll => __x64_sys_poll => do_syscall_64 => 0x966000aa
<...>-153 [006] d..4. 562.068407: block_lat: pid=153 delta=54 stack=STACK: => __schedule => schedule => io_schedule => rq_qos_wait => wbt_wait => __rq_qos_throttle => blk_mq_submit_bio => submit_bio_noacct_nocheck => ext4_bio_write_page => mpage_submit_page => mpage_process_page_bufs => mpage_prepare_extent_to_map => ext4_do_writepages => ext4_writepages => do_writepages => __writeback_single_inode
Link: https://lkml.kernel.org/r/20230117152236.010941267@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Ross Zwisler <zwisler@google.com> Cc: Ching-lin Yu <chinglinyu@google.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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#
288709c9 |
| 17-Jan-2023 |
Steven Rostedt (Google) <rostedt@goodmis.org> |
tracing: Allow stacktraces to be saved as histogram variables
Allow to save stacktraces into a histogram variable. This will be used by synthetic events to allow a stacktrace from one event to be pa
tracing: Allow stacktraces to be saved as histogram variables
Allow to save stacktraces into a histogram variable. This will be used by synthetic events to allow a stacktrace from one event to be passed and displayed by another event.
The special keyword "stacktrace" is to be used to trigger a stack trace for the event that the histogram trigger is attached to.
echo 'hist:keys=pid:st=stacktrace" > events/sched/sched_waking/trigger
Currently nothing can get access to the "$st" variable above that contains the stack trace, but that will soon change.
Link: https://lkml.kernel.org/r/20230117152235.856323729@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Ross Zwisler <zwisler@google.com> Cc: Ching-lin Yu <chinglinyu@google.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Revision tags: v6.1.6, v6.1.5, v6.0.19 |
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#
8b152e91 |
| 11-Jan-2023 |
Natalia Petrova <n.petrova@fintech.ru> |
trace_events_hist: add check for return value of 'create_hist_field'
Function 'create_hist_field' is called recursively at trace_events_hist.c:1954 and can return NULL-value that's why we have to ch
trace_events_hist: add check for return value of 'create_hist_field'
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: 30350d65ac56 ("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>
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Revision tags: v6.0.18, v6.1.4, v6.1.3, v6.0.17, v6.1.2, v6.0.16, v6.1.1, v6.0.15, v6.0.14, v6.0.13, v6.1, v6.0.12 |
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#
608c6ed3 |
| 07-Dec-2022 |
Zheng Yejian <zhengyejian1@huawei.com> |
tracing/hist: Fix issue of losting command info in error_log
When input some constructed invalid 'trigger' command, command info in 'error_log' are lost [1].
The root cause is that there is a path
tracing/hist: Fix issue of losting command info in error_log
When input some constructed invalid 'trigger' command, command info in 'error_log' are lost [1].
The root cause is that there is a path that event_hist_trigger_parse() is recursely called once and 'last_cmd' which save origin command is cleared, then later calling of hist_err() will no longer record origin command info:
event_hist_trigger_parse() { last_cmd_set() // <1> 'last_cmd' save origin command here at first create_actions() { onmatch_create() { action_create() { trace_action_create() { trace_action_create_field_var() { create_field_var_hist() { event_hist_trigger_parse() { // <2> recursely called once hist_err_clear() // <3> 'last_cmd' is cleared here } hist_err() // <4> No longer find origin command!!!
Since 'glob' is empty string while running into the recurse call, we can trickly check it and bypass the call of hist_err_clear() to solve it.
[1] # cd /sys/kernel/tracing # echo "my_synth_event int v1; int v2; int v3;" >> synthetic_events # echo 'hist:keys=pid' >> events/sched/sched_waking/trigger # echo "hist:keys=next_pid:onmatch(sched.sched_waking).my_synth_event(\ pid,pid1)" >> events/sched/sched_switch/trigger # cat error_log [ 8.405018] hist:sched:sched_switch: error: Couldn't find synthetic event Command: hist:keys=next_pid:onmatch(sched.sched_waking).my_synth_event(pid,pid1) ^ [ 8.816902] hist:sched:sched_switch: error: Couldn't find field Command: hist:keys=next_pid:onmatch(sched.sched_waking).my_synth_event(pid,pid1) ^ [ 8.816902] hist:sched:sched_switch: error: Couldn't parse field variable Command: hist:keys=next_pid:onmatch(sched.sched_waking).my_synth_event(pid,pid1) ^ [ 8.999880] : error: Couldn't find field Command: ^ [ 8.999880] : error: Couldn't parse field variable Command: ^ [ 8.999880] : error: Couldn't find field Command: ^ [ 8.999880] : error: Couldn't create histogram for field Command: ^
Link: https://lore.kernel.org/linux-trace-kernel/20221207135326.3483216-1-zhengyejian1@huawei.com
Cc: <mhiramat@kernel.org> Cc: <zanussi@kernel.org> Fixes: f404da6e1d46 ("tracing: Add 'last error' error facility for hist triggers") Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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#
82470f7d |
| 06-Dec-2022 |
Zheng Yejian <zhengyejian1@huawei.com> |
tracing/hist: Fix out-of-bound write on 'action_data.var_ref_idx'
When generate a synthetic event with many params and then create a trace action for it [1], kernel panic happened [2].
It is becaus
tracing/hist: Fix out-of-bound write on 'action_data.var_ref_idx'
When generate a synthetic event with many params and then create a trace action for it [1], kernel panic happened [2].
It is because that in trace_action_create() 'data->n_params' is up to SYNTH_FIELDS_MAX (current value is 64), and array 'data->var_ref_idx' keeps indices into array 'hist_data->var_refs' for each synthetic event param, but the length of 'data->var_ref_idx' is TRACING_MAP_VARS_MAX (current value is 16), so out-of-bound write happened when 'data->n_params' more than 16. In this case, 'data->match_data.event' is overwritten and eventually cause the panic.
To solve the issue, adjust the length of 'data->var_ref_idx' to be SYNTH_FIELDS_MAX and add sanity checks to avoid out-of-bound write.
[1] # cd /sys/kernel/tracing/ # echo "my_synth_event int v1; int v2; int v3; int v4; int v5; int v6;\ int v7; int v8; int v9; int v10; int v11; int v12; int v13; int v14;\ int v15; int v16; int v17; int v18; int v19; int v20; int v21; int v22;\ int v23; int v24; int v25; int v26; int v27; int v28; int v29; int v30;\ int v31; int v32; int v33; int v34; int v35; int v36; int v37; int v38;\ int v39; int v40; int v41; int v42; int v43; int v44; int v45; int v46;\ int v47; int v48; int v49; int v50; int v51; int v52; int v53; int v54;\ int v55; int v56; int v57; int v58; int v59; int v60; int v61; int v62;\ int v63" >> synthetic_events # echo 'hist:keys=pid:ts0=common_timestamp.usecs if comm=="bash"' >> \ events/sched/sched_waking/trigger # echo "hist:keys=next_pid:onmatch(sched.sched_waking).my_synth_event(\ pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,\ pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,\ pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,pid,\ pid,pid,pid,pid,pid,pid,pid,pid,pid)" >> events/sched/sched_switch/trigger
[2] BUG: unable to handle page fault for address: ffff91c900000000 PGD 61001067 P4D 61001067 PUD 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 2 PID: 322 Comm: bash Tainted: G W 6.1.0-rc8+ #229 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 RIP: 0010:strcmp+0xc/0x30 Code: 75 f7 31 d2 44 0f b6 04 16 44 88 04 11 48 83 c2 01 45 84 c0 75 ee c3 cc cc cc cc 0f 1f 00 31 c0 eb 08 48 83 c0 01 84 d2 74 13 <0f> b6 14 07 3a 14 06 74 ef 19 c0 83 c8 01 c3 cc cc cc cc 31 c3 RSP: 0018:ffff9b3b00f53c48 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffffffba958a68 RCX: 0000000000000000 RDX: 0000000000000010 RSI: ffff91c943d33a90 RDI: ffff91c900000000 RBP: ffff91c900000000 R08: 00000018d604b529 R09: 0000000000000000 R10: ffff91c9483eddb1 R11: ffff91ca483eddab R12: ffff91c946171580 R13: ffff91c9479f0538 R14: ffff91c9457c2848 R15: ffff91c9479f0538 FS: 00007f1d1cfbe740(0000) GS:ffff91c9bdc80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff91c900000000 CR3: 0000000006316000 CR4: 00000000000006e0 Call Trace: <TASK> __find_event_file+0x55/0x90 action_create+0x76c/0x1060 event_hist_trigger_parse+0x146d/0x2060 ? event_trigger_write+0x31/0xd0 trigger_process_regex+0xbb/0x110 event_trigger_write+0x6b/0xd0 vfs_write+0xc8/0x3e0 ? alloc_fd+0xc0/0x160 ? preempt_count_add+0x4d/0xa0 ? preempt_count_add+0x70/0xa0 ksys_write+0x5f/0xe0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f1d1d0cf077 Code: 64 89 02 48 c7 c0 ff ff ff ff eb bb 0f 1f 80 00 00 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 RSP: 002b:00007ffcebb0e568 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000143 RCX: 00007f1d1d0cf077 RDX: 0000000000000143 RSI: 00005639265aa7e0 RDI: 0000000000000001 RBP: 00005639265aa7e0 R08: 000000000000000a R09: 0000000000000142 R10: 000056392639c017 R11: 0000000000000246 R12: 0000000000000143 R13: 00007f1d1d1ae6a0 R14: 00007f1d1d1aa4a0 R15: 00007f1d1d1a98a0 </TASK> Modules linked in: CR2: ffff91c900000000 ---[ end trace 0000000000000000 ]--- RIP: 0010:strcmp+0xc/0x30 Code: 75 f7 31 d2 44 0f b6 04 16 44 88 04 11 48 83 c2 01 45 84 c0 75 ee c3 cc cc cc cc 0f 1f 00 31 c0 eb 08 48 83 c0 01 84 d2 74 13 <0f> b6 14 07 3a 14 06 74 ef 19 c0 83 c8 01 c3 cc cc cc cc 31 c3 RSP: 0018:ffff9b3b00f53c48 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffffffba958a68 RCX: 0000000000000000 RDX: 0000000000000010 RSI: ffff91c943d33a90 RDI: ffff91c900000000 RBP: ffff91c900000000 R08: 00000018d604b529 R09: 0000000000000000 R10: ffff91c9483eddb1 R11: ffff91ca483eddab R12: ffff91c946171580 R13: ffff91c9479f0538 R14: ffff91c9457c2848 R15: ffff91c9479f0538 FS: 00007f1d1cfbe740(0000) GS:ffff91c9bdc80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff91c900000000 CR3: 0000000006316000 CR4: 00000000000006e0
Link: https://lore.kernel.org/linux-trace-kernel/20221207035143.2278781-1-zhengyejian1@huawei.com
Cc: <mhiramat@kernel.org> Cc: <zanussi@kernel.org> Cc: stable@vger.kernel.org Fixes: d380dcde9a07 ("tracing: Fix now invalid var_ref_vals assumption in trace action") Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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#
2cc6a528 |
| 06-Dec-2022 |
Zheng Yejian <zhengyejian1@huawei.com> |
tracing/hist: Fix wrong return value in parse_action_params()
When number of synth fields is more than SYNTH_FIELDS_MAX, parse_action_params() should return -EINVAL.
Link: https://lore.kernel.org/l
tracing/hist: Fix wrong return value in parse_action_params()
When number of synth fields is more than SYNTH_FIELDS_MAX, parse_action_params() should return -EINVAL.
Link: https://lore.kernel.org/linux-trace-kernel/20221207034635.2253990-1-zhengyejian1@huawei.com
Cc: <mhiramat@kernel.org> Cc: <zanussi@kernel.org> Cc: stable@vger.kernel.org Fixes: c282a386a397 ("tracing: Add 'onmatch' hist trigger action support") Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Revision tags: v6.0.11, v6.0.10, v5.15.80, v6.0.9, v5.15.79, v6.0.8, v5.15.78, v6.0.7, v5.15.77, v5.15.76, v6.0.6, v6.0.5, v5.15.75, v6.0.4, v6.0.3 |
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#
ccf47f5c |
| 19-Oct-2022 |
Masami Hiramatsu (Google) <mhiramat@kernel.org> |
tracing: Add nohitcount option for suppressing display of raw hitcount
Add 'nohitcount' ('NOHC' for short) option for suppressing display of the raw hitcount column in the histogram. Note that you m
tracing: Add nohitcount option for suppressing display of raw hitcount
Add 'nohitcount' ('NOHC' for short) option for suppressing display of the raw hitcount column in the histogram. Note that you must specify at least one value except raw 'hitcount' when you specify this nohitcount option.
# cd /sys/kernel/debug/tracing/ # echo hist:keys=pid:vals=runtime.percent,runtime.graph:sort=pid:NOHC > \ events/sched/sched_stat_runtime/trigger # sleep 10 # cat events/sched/sched_stat_runtime/hist # event histogram # # trigger info: hist:keys=pid:vals=runtime.percent,runtime.graph:sort=pid:size=2048:nohitcount [active] #
{ pid: 8 } runtime (%): 3.02 runtime: # { pid: 14 } runtime (%): 2.25 runtime: { pid: 16 } runtime (%): 2.25 runtime: { pid: 26 } runtime (%): 0.17 runtime: { pid: 61 } runtime (%): 11.52 runtime: #### { pid: 67 } runtime (%): 1.56 runtime: { pid: 68 } runtime (%): 0.84 runtime: { pid: 76 } runtime (%): 0.92 runtime: { pid: 117 } runtime (%): 2.50 runtime: # { pid: 146 } runtime (%): 49.88 runtime: #################### { pid: 157 } runtime (%): 16.63 runtime: ###### { pid: 158 } runtime (%): 8.38 runtime: ###
Link: https://lore.kernel.org/linux-trace-kernel/166610814787.56030.4980636083486339906.stgit@devnote2
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Tom Zanussi <zanussi@kernel.org> Tested-by: Tom Zanussi <zanussi@kernel.org>
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#
a2c54256 |
| 19-Oct-2022 |
Masami Hiramatsu (Google) <mhiramat@kernel.org> |
tracing: Add .graph suffix option to histogram value
Add the .graph suffix which shows the bar graph of the histogram value.
For example, the below example shows that the bar graph of the histogram
tracing: Add .graph suffix option to histogram value
Add the .graph suffix which shows the bar graph of the histogram value.
For example, the below example shows that the bar graph of the histogram of the runtime for each tasks.
------ # cd /sys/kernel/debug/tracing/ # echo hist:keys=pid:vals=runtime.graph:sort=pid > \ events/sched/sched_stat_runtime/trigger # sleep 10 # cat events/sched/sched_stat_runtime/hist # event histogram # # trigger info: hist:keys=pid:vals=hitcount,runtime.graph:sort=pid:size=2048 [active] #
{ pid: 14 } hitcount: 2 runtime: { pid: 16 } hitcount: 8 runtime: { pid: 26 } hitcount: 1 runtime: { pid: 57 } hitcount: 3 runtime: { pid: 61 } hitcount: 20 runtime: ### { pid: 66 } hitcount: 2 runtime: { pid: 70 } hitcount: 3 runtime: { pid: 72 } hitcount: 2 runtime: { pid: 145 } hitcount: 14 runtime: #################### { pid: 152 } hitcount: 5 runtime: ####### { pid: 153 } hitcount: 2 runtime: ####
Totals: Hits: 62 Entries: 11 Dropped: 0 -------
Link: https://lore.kernel.org/linux-trace-kernel/166610813953.56030.10944148382315789485.stgit@devnote2
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Tom Zanussi <zanussi@kernel.org> Tested-by: Tom Zanussi <zanussi@kernel.org>
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abaa5258 |
| 19-Oct-2022 |
Masami Hiramatsu (Google) <mhiramat@kernel.org> |
tracing: Add .percent suffix option to histogram values
Add .percent suffix option to show the histogram values in percentage. This feature is useful when we need yo undersntand the overall trend fo
tracing: Add .percent suffix option to histogram values
Add .percent suffix option to show the histogram values in percentage. This feature is useful when we need yo undersntand the overall trend for the histograms of large values. E.g. this shows the runtime percentage for each tasks.
------ # cd /sys/kernel/debug/tracing/ # echo hist:keys=pid:vals=hitcount,runtime.percent:sort=pid > \ events/sched/sched_stat_runtime/trigger # sleep 10 # cat events/sched/sched_stat_runtime/hist # event histogram # # trigger info: hist:keys=pid:vals=hitcount,runtime.percent:sort=pid:size=2048 [active] #
{ pid: 8 } hitcount: 7 runtime (%): 4.14 { pid: 14 } hitcount: 5 runtime (%): 3.69 { pid: 16 } hitcount: 11 runtime (%): 3.41 { pid: 61 } hitcount: 41 runtime (%): 19.75 { pid: 65 } hitcount: 4 runtime (%): 1.48 { pid: 70 } hitcount: 6 runtime (%): 3.60 { pid: 72 } hitcount: 2 runtime (%): 1.10 { pid: 144 } hitcount: 10 runtime (%): 32.01 { pid: 151 } hitcount: 8 runtime (%): 22.66 { pid: 152 } hitcount: 2 runtime (%): 8.10
Totals: Hits: 96 Entries: 10 Dropped: 0 -----
Link: https://lore.kernel.org/linux-trace-kernel/166610813077.56030.4238090506973562347.stgit@devnote2
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Tom Zanussi <zanussi@kernel.org> Tested-by: Tom Zanussi <zanussi@kernel.org>
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5f2e094e |
| 19-Oct-2022 |
Tom Zanussi <zanussi@kernel.org> |
tracing: Allow multiple hitcount values in histograms
The hitcount is treated specially in the histograms - since it's always expected to be there regardless of whether the user specified anything o
tracing: Allow multiple hitcount values in histograms
The hitcount is treated specially in the histograms - since it's always expected to be there regardless of whether the user specified anything or not, it's always added as the first histogram value.
Currently the code doesn't allow it to be added more than once as a value, which is inconsistent with all the other possible values. It would seem to be a pointless thing to want to do, but other features being added such as percent and graph modifiers don't work properly with the current hitcount restrictions.
Fix this by allowing multiple hitcounts to be added.
Link: https://lore.kernel.org/linux-trace-kernel/166610812248.56030.16754785928712505251.stgit@devnote2
Signed-off-by: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Tested-by: Tom Zanussi <zanussi@kernel.org>
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ef38c79a |
| 23-Nov-2022 |
Steven Rostedt (Google) <rostedt@goodmis.org> |
tracing: Fix race where histograms can be called before the event
commit 94eedf3dded5 ("tracing: Fix race where eprobes can be called before the event") fixed an issue where if an event is soft disa
tracing: Fix race where histograms can be called before the event
commit 94eedf3dded5 ("tracing: Fix race where eprobes can be called before the event") fixed an issue where if an event is soft disabled, and the trigger is being added, there's a small window where the event sees that there's a trigger but does not see that it requires reading the event yet, and then calls the trigger with the record == NULL.
This could be solved with adding memory barriers in the hot path, or to make sure that all the triggers requiring a record check for NULL. The latter was chosen.
Commit 94eedf3dded5 set the eprobe trigger handle to check for NULL, but the same needs to be done with histograms.
Link: https://lore.kernel.org/linux-trace-kernel/20221118211809.701d40c0f8a757b0df3c025a@kernel.org/ Link: https://lore.kernel.org/linux-trace-kernel/20221123164323.03450c3a@gandalf.local.home
Cc: Tom Zanussi <zanussi@kernel.org> Cc: stable@vger.kernel.org Fixes: 7491e2c442781 ("tracing: Add a probe that attaches to trace events") Reported-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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0a068f4a |
| 20-Oct-2022 |
Colin Ian King <colin.i.king@gmail.com> |
tracing/hist: add in missing * in comment blocks
There are a couple of missing * in comment blocks. Fix these. Cleans up two clang warnings:
kernel/trace/trace_events_hist.c:986: warning: bad line:
tracing/hist: add in missing * in comment blocks
There are a couple of missing * in comment blocks. Fix these. Cleans up two clang warnings:
kernel/trace/trace_events_hist.c:986: warning: bad line: kernel/trace/trace_events_hist.c:3229: warning: bad line:
Link: https://lkml.kernel.org/r/20221020133019.1547587-1-colin.i.king@gmail.com
Signed-off-by: Colin Ian King <colin.i.king@gmail.com> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Revision tags: v6.0.2, v5.15.74, v5.15.73, v6.0.1, v5.15.72, v6.0, v5.15.71, v5.15.70, v5.15.69, v5.15.68, v5.15.67, v5.15.66 |
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86087383 |
| 06-Sep-2022 |
Steven Rostedt (Google) <rostedt@goodmis.org> |
tracing/hist: Call hist functions directly via a switch statement
Due to retpolines, indirect calls are much more expensive than direct calls. The histograms have a select set of functions it uses f
tracing/hist: Call hist functions directly via a switch statement
Due to retpolines, indirect calls are much more expensive than direct calls. The histograms have a select set of functions it uses for the histograms, instead of using function pointers to call them, create a hist_fn_call() function that uses a switch statement to call the histogram functions directly. This gives a 13% speedup to the histogram logic.
Using the histogram benchmark:
Before:
# event histogram # # trigger info: hist:keys=delta:vals=hitcount:sort=delta:size=2048 if delta > 0 [active] #
{ delta: 129 } hitcount: 2213 { delta: 130 } hitcount: 285965 { delta: 131 } hitcount: 1146545 { delta: 132 } hitcount: 5185432 { delta: 133 } hitcount: 19896215 { delta: 134 } hitcount: 53118616 { delta: 135 } hitcount: 83816709 { delta: 136 } hitcount: 68329562 { delta: 137 } hitcount: 41859349 { delta: 138 } hitcount: 46257797 { delta: 139 } hitcount: 54400831 { delta: 140 } hitcount: 72875007 { delta: 141 } hitcount: 76193272 { delta: 142 } hitcount: 49504263 { delta: 143 } hitcount: 38821072 { delta: 144 } hitcount: 47702679 { delta: 145 } hitcount: 41357297 { delta: 146 } hitcount: 22058238 { delta: 147 } hitcount: 9720002 { delta: 148 } hitcount: 3193542 { delta: 149 } hitcount: 927030 { delta: 150 } hitcount: 850772 { delta: 151 } hitcount: 1477380 { delta: 152 } hitcount: 2687977 { delta: 153 } hitcount: 2865985 { delta: 154 } hitcount: 1977492 { delta: 155 } hitcount: 2475607 { delta: 156 } hitcount: 3403612
After:
# event histogram # # trigger info: hist:keys=delta:vals=hitcount:sort=delta:size=2048 if delta > 0 [active] #
{ delta: 113 } hitcount: 272 { delta: 114 } hitcount: 840 { delta: 118 } hitcount: 344 { delta: 119 } hitcount: 25428 { delta: 120 } hitcount: 350590 { delta: 121 } hitcount: 1892484 { delta: 122 } hitcount: 6205004 { delta: 123 } hitcount: 11583521 { delta: 124 } hitcount: 37590979 { delta: 125 } hitcount: 108308504 { delta: 126 } hitcount: 131672461 { delta: 127 } hitcount: 88700598 { delta: 128 } hitcount: 65939870 { delta: 129 } hitcount: 45055004 { delta: 130 } hitcount: 33174464 { delta: 131 } hitcount: 31813493 { delta: 132 } hitcount: 29011676 { delta: 133 } hitcount: 22798782 { delta: 134 } hitcount: 22072486 { delta: 135 } hitcount: 17034113 { delta: 136 } hitcount: 8982490 { delta: 137 } hitcount: 2865908 { delta: 138 } hitcount: 980382 { delta: 139 } hitcount: 1651944 { delta: 140 } hitcount: 4112073 { delta: 141 } hitcount: 3963269 { delta: 142 } hitcount: 1712508 { delta: 143 } hitcount: 575941 { delta: 144 } hitcount: 351427 { delta: 145 } hitcount: 218077 { delta: 146 } hitcount: 167297 { delta: 147 } hitcount: 146198 { delta: 148 } hitcount: 116122 { delta: 149 } hitcount: 58993 { delta: 150 } hitcount: 40228
The delta above is in nanoseconds. It brings the fastest time down from 129ns to 113ns, and the peak from 141ns to 126ns.
Link: https://lkml.kernel.org/r/20220906225529.411545333@goodmis.org
Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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