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2021-11-12tracing/histogram: Do not copy the fixed-size char array field over the ↵Masami Hiramatsu1-4/+5
field size Do not copy the fixed-size char array field of the events over the field size. The histogram treats char array as a string and there are 2 types of char array in the event, fixed-size and dynamic string. The dynamic string (__data_loc) field must be null terminated, but the fixed-size char array field may not be null terminated (not a string, but just a data). In that case, histogram can copy the data after the field. This uses the original field size for fixed-size char array field to restrict the histogram not to access over the original field size. Link: https://lkml.kernel.org/r/163673292822.195747.3696966210526410250.stgit@devnote2 Fixes: 02205a6752f2 (tracing: Add support for 'field variables') Signed-off-by: Masami Hiramatsu <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-11-12tracing/osnoise: Make osnoise_instances staticDaniel Bristot de Oliveira1-1/+2
Make the struct list_head osnoise_instances definition static. Link: https://lore.kernel.org/all/[email protected]/ Link: https://lkml.kernel.org/r/d001f0eeac66e2b2eeec7d2a15e9e7abede0453a.1636667971.git.bristot@kernel.org Cc: Ingo Molnar <[email protected]> Fixes: dae181349f1e ("tracing/osnoise: Support a list of trace_array *tr") Reported-by: kernel test robot <[email protected]> Signed-off-by: Daniel Bristot de Oliveira <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-11-10ftrace/direct: Fix lockup in modify_ftrace_direct_multiJiri Olsa1-1/+2
We can't call unregister_ftrace_function under ftrace_lock. Link: https://lkml.kernel.org/r/[email protected] Fixes: ed29271894aa ("ftrace/direct: Do not disable when switching direct callers") Signed-off-by: Jiri Olsa <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-11-10ring-buffer: Protect ring_buffer_reset() from reentrancySteven Rostedt (VMware)1-0/+5
The resetting of the entire ring buffer use to simply go through and reset each individual CPU buffer that had its own protection and synchronization. But this was very slow, due to performing a synchronization for each CPU. The code was reshuffled to do one disabling of all CPU buffers, followed by a single RCU synchronization, and then the resetting of each of the CPU buffers. But unfortunately, the mutex that prevented multiple occurrences of resetting the buffer was not moved to the upper function, and there is nothing to protect from it. Take the ring buffer mutex around the global reset. Cc: [email protected] Fixes: b23d7a5f4a07a ("ring-buffer: speed up buffer resets by avoiding synchronize_rcu for each CPU") Reported-by: "Tzvetomir Stoyanov (VMware)" <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-11-01ftrace/samples: Add missing prototype for my_direct_funcJiri Olsa1-0/+2
There's compilation fail reported kernel test robot for W=1 build: >> samples/ftrace/ftrace-direct-multi.c:8:6: warning: no previous prototype for function 'my_direct_func' [-Wmissing-prototypes] void my_direct_func(unsigned long ip) The inlined assembly is used outside function, so we can't make my_direct_func static and pass it as asm input argument. However my_tramp is already extern so I think there's no problem keeping my_direct_func extern as well and just add its prototype. Link: https://lkml.kernel.org/r/[email protected] Reported-by: kernel test robot <[email protected]> Fixes: 5fae941b9a6f ("ftrace/samples: Add multi direct interface test module") Signed-off-by: Jiri Olsa <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-11-01tracing/selftests: Add tests for hist trigger expression parsingKalesh Singh1-0/+63
Add tests for the parsing of hist trigger expressions; and to validate expression evaluation. Link: https://lkml.kernel.org/r/[email protected] Cc: Jonathan Corbet <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Shuah Khan <[email protected]> Cc: Tom Zanussi <[email protected]> Signed-off-by: Kalesh Singh <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-11-01tracing/histogram: Document hist trigger variablesKalesh Singh1-0/+11
Update the tracefs README to describe how hist trigger variables can be created. Link: https://lkml.kernel.org/r/[email protected] Cc: Jonathan Corbet <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Shuah Khan <[email protected]> Cc: Tom Zanussi <[email protected]> Signed-off-by: Kalesh Singh <[email protected]> Acked-by: Masami Hiramatsu <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-11-01tracing/histogram: Update division by 0 documentationKalesh Singh1-1/+2
If the divisor is a constant and zero, the undeifned case can be detected and an error returned instead of -1. Link: https://lkml.kernel.org/r/[email protected] Cc: Jonathan Corbet <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Shuah Khan <[email protected]> Cc: Tom Zanussi <[email protected]> Signed-off-by: Kalesh Singh <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-11-01tracing/histogram: Optimize division by constantsKalesh Singh1-1/+104
If the divisor is a constant use specific division functions to avoid extra branches when the trigger is hit. If the divisor constant but not a power of 2, the division can be replaced with a multiplication and shift in the following case: Let X = dividend and Y = divisor. Choose Z = some power of 2. If Y <= Z, then: X / Y = (X * (Z / Y)) / Z (Z / Y) is a constant (mult) which is calculated at parse time, so: X / Y = (X * mult) / Z The division by Z can be replaced by a shift since Z is a power of 2: X / Y = (X * mult) >> shift As long, as X < Z the results will not be off by more than 1. Link: https://lkml.kernel.org/r/[email protected] Suggested-by: Steven Rostedt <[email protected]> Signed-off-by: Kalesh Singh <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-11-01tracing/osnoise: Remove PREEMPT_RT ifdefs from inside functionsDaniel Bristot de Oliveira1-9/+4
Remove CONFIG_PREEMPT_RT from inside functions, avoiding compilation problems in the future. Link: https://lkml.kernel.org/r/37ee0881b033cdc513efc84ebea26cf77880c8c2.1635702894.git.bristot@kernel.org Cc: Ingo Molnar <[email protected]> Cc: Tom Zanussi <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: Juri Lelli <[email protected]> Cc: Clark Williams <[email protected]> Cc: John Kacur <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Sebastian Andrzej Siewior <[email protected]> Cc: Daniel Bristot de Oliveira <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Suggested-by: Steven Rostedt <[email protected]> Signed-off-by: Daniel Bristot de Oliveira <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-11-01tracing/osnoise: Remove STACKTRACE ifdefs from inside functionsDaniel Bristot de Oliveira1-15/+29
Remove CONFIG_STACKTRACE from inside functions, avoiding compilation problems in the future. Link: https://lkml.kernel.org/r/3465cca2f28e1ba602a1fc8bdb28d12950b5226e.1635702894.git.bristot@kernel.org Cc: Ingo Molnar <[email protected]> Cc: Tom Zanussi <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: Juri Lelli <[email protected]> Cc: Clark Williams <[email protected]> Cc: John Kacur <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Sebastian Andrzej Siewior <[email protected]> Cc: Daniel Bristot de Oliveira <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Suggested-by: Steven Rostedt <[email protected]> Signed-off-by: Daniel Bristot de Oliveira <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-11-01tracing/osnoise: Allow multiple instances of the same tracerDaniel Bristot de Oliveira1-23/+78
Currently, the user can start only one instance of timerlat/osnoise tracers and the tracers cannot run in parallel. As starting point to add more flexibility, let's allow the same tracer to run on different trace instances. The workload will start when the first trace_array (instance) is registered and stop when the last instance is unregistered. So, while this patch allows the same tracer to run in multiple instances (e.g., two instances running osnoise), it still does not allow instances of timerlat and osnoise in parallel (e.g., one timerlat and osnoise). That is because the osnoise: events have different behavior depending on which tracer is enabled (osnoise or timerlat). Enabling the parallel usage of these two tracers is in my TODO list. Link: https://lkml.kernel.org/r/38c8f14b613492a4f3f938d9d3bf0b063b72f0f0.1635702894.git.bristot@kernel.org Cc: Ingo Molnar <[email protected]> Cc: Tom Zanussi <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: Juri Lelli <[email protected]> Cc: Clark Williams <[email protected]> Cc: John Kacur <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Sebastian Andrzej Siewior <[email protected]> Cc: Daniel Bristot de Oliveira <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Signed-off-by: Daniel Bristot de Oliveira <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-11-01tracing/osnoise: Remove TIMERLAT ifdefs from inside functionsDaniel Bristot de Oliveira1-44/+106
Remove CONFIG_TIMERLAT_TRACER from inside functions, avoiding compilation problems in the future. Link: https://lkml.kernel.org/r/8245abb5a112d249f5da6c1df499244ad9e647bc.1635702894.git.bristot@kernel.org Cc: Ingo Molnar <[email protected]> Cc: Tom Zanussi <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: Juri Lelli <[email protected]> Cc: Clark Williams <[email protected]> Cc: John Kacur <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Sebastian Andrzej Siewior <[email protected]> Cc: Daniel Bristot de Oliveira <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Suggested-by: Steven Rostedt <[email protected]> Signed-off-by: Daniel Bristot de Oliveira <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-11-01tracing/osnoise: Support a list of trace_array *trDaniel Bristot de Oliveira1-69/+192
osnoise/timerlat were built to run a single instance, and for this, a single variable is enough to store the current struct trace_array *tr with information about the tracing instance. This is done via the *osnoise_trace variable. A trace_array represents a trace instance. In preparation to support multiple instances, replace the *osnoise_trace variable with an RCU protected list of instances. The operations that refer to an instance now propagate to all elements of the list (all instances). Also, replace the osnoise_busy variable with a check if the list has elements (busy). No functional change is expected with this patch, i.e., only one instance is allowed yet. Link: https://lkml.kernel.org/r/91d006e889b9a5d1ff258fe6077f021ae3f26372.1635702894.git.bristot@kernel.org Cc: Ingo Molnar <[email protected]> Cc: Tom Zanussi <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: Juri Lelli <[email protected]> Cc: Clark Williams <[email protected]> Cc: John Kacur <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Sebastian Andrzej Siewior <[email protected]> Cc: Daniel Bristot de Oliveira <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Signed-off-by: Daniel Bristot de Oliveira <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-11-01tracing/osnoise: Use start/stop_per_cpu_kthreads() on osnoise_cpus_write()Daniel Bristot de Oliveira1-5/+2
When writing a new CPU mask via osnoise/cpus, if the tracer is running, the workload is restarted to follow the new cpumask. The restart is currently done using osnoise_workload_start/stop(), which disables the workload *and* the instrumentation. However, disabling the instrumentation is not necessary. Calling start/stop_per_cpu_kthreads() is enough to apply the new osnoise/cpus config. Link: https://lkml.kernel.org/r/ee633e82867c5b88851aa6040522a799c0034486.1635702894.git.bristot@kernel.org Cc: Ingo Molnar <[email protected]> Cc: Tom Zanussi <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: Juri Lelli <[email protected]> Cc: Clark Williams <[email protected]> Cc: John Kacur <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Sebastian Andrzej Siewior <[email protected]> Cc: Daniel Bristot de Oliveira <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Signed-off-by: Daniel Bristot de Oliveira <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-11-01tracing/osnoise: Split workload start from the tracer startDaniel Bristot de Oliveira1-23/+36
In preparation from supporting multiple trace instances, create workload start/stop specific functions. No functional change. Link: https://lkml.kernel.org/r/74b090971e9acdd13625be1c28ef3270d2275e77.1635702894.git.bristot@kernel.org Cc: Ingo Molnar <[email protected]> Cc: Tom Zanussi <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: Juri Lelli <[email protected]> Cc: Clark Williams <[email protected]> Cc: John Kacur <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Sebastian Andrzej Siewior <[email protected]> Cc: Daniel Bristot de Oliveira <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Signed-off-by: Daniel Bristot de Oliveira <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-11-01tracing/osnoise: Improve comments about barrier need for NMI callbacksDaniel Bristot de Oliveira1-1/+7
trace_osnoise_callback_enabled is used by ftrace_nmi_enter/exit() to know when to call the NMI callback. The barrier is used to avoid having callbacks enabled before the resetting date during the start or to touch the values after stopping the tracer. Link: https://lkml.kernel.org/r/a413b8f14aa9312fbd1ba99f96225a8aed831053.1635702894.git.bristot@kernel.org Cc: Ingo Molnar <[email protected]> Cc: Tom Zanussi <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: Juri Lelli <[email protected]> Cc: Clark Williams <[email protected]> Cc: John Kacur <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Sebastian Andrzej Siewior <[email protected]> Cc: Daniel Bristot de Oliveira <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Suggested-by: Steven Rostedt <[email protected]> Signed-off-by: Daniel Bristot de Oliveira <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-11-01tracing/osnoise: Do not follow tracing_cpumaskDaniel Bristot de Oliveira1-18/+6
In preparation to support multiple instances, decouple the osnoise/timelat workload from instance-specific tracing_cpumask. Different instances can have conflicting cpumasks, making osnoise workload management needlessly complex. Osnoise already has its global cpumask. I also thought about using the first instance mask, but the "first" instance could be removed before the others. This also fixes the problem that changing the tracing_mask was not re-starting the trace. Link: https://lkml.kernel.org/r/169a71bcc919ce3ab53ae6f9ca5cde57fffaf9c6.1635702894.git.bristot@kernel.org Cc: Ingo Molnar <[email protected]> Cc: Tom Zanussi <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: Juri Lelli <[email protected]> Cc: Clark Williams <[email protected]> Cc: John Kacur <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Sebastian Andrzej Siewior <[email protected]> Cc: Daniel Bristot de Oliveira <[email protected]> Cc: [email protected] Cc: [email protected] Signed-off-by: Daniel Bristot de Oliveira <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-29tracing/histogram: Fix semicolon.cocci warningskernel test robot1-1/+1
kernel/trace/trace_events_hist.c:6039:2-3: Unneeded semicolon Remove unneeded semicolon. Generated by: scripts/coccinelle/misc/semicolon.cocci Link: https://lkml.kernel.org/r/20211030005615.GA41257@3074f0d39c61 Fixes: c5eac6ee8bc5 ("tracing/histogram: Simplify handling of .sym-offset in expressions") CC: Kalesh Singh <[email protected]> Reported-by: kernel test robot <[email protected]> Signed-off-by: kernel test robot <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-28tracing/histogram: Fix documentation inline emphasis warningKalesh Singh1-1/+1
This fixes the warning: Documentation/trace/histogram.rst:1766: WARNING: Inline emphasis start-string without end-string The issue was caused by an unescaped '*' character. Link: https://lore.kernel.org/all/[email protected]/T/#m77da47432f5cc6521d4294ffdb9621949cc35d04 Link: https://lkml.kernel.org/r/[email protected] Fixes: 2d2f6d4b8ce7 ("tracing/histogram: Document expression arithmetic and constants") Reported-by: Stephen Rothwell <[email protected]> Signed-off-by: Kalesh Singh <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-27tracing: Increase PERF_MAX_TRACE_SIZE to handle Sentinel1 and docker togetherRobin H. Johnson1-1/+1
Running endpoint security solutions like Sentinel1 that use perf-based tracing heavily lead to this repeated dump complaining about dockerd. The default value of 2048 is nowhere near not large enough. Using the prior patch "tracing: show size of requested buffer", we get "perf buffer not large enough, wanted 6644, have 6144", after repeated up-sizing (I did 2/4/6/8K). With 8K, the problem doesn't occur at all, so below is the trace for 6K. I'm wondering if this value should be selectable at boot time, but this is a good starting point. ``` ------------[ cut here ]------------ perf buffer not large enough, wanted 6644, have 6144 WARNING: CPU: 1 PID: 4997 at kernel/trace/trace_event_perf.c:402 perf_trace_buf_alloc+0x8c/0xa0 Modules linked in: [..] CPU: 1 PID: 4997 Comm: sh Tainted: G T 5.13.13-x86_64-00039-gb3959163488e #63 Hardware name: LENOVO 20KH002JUS/20KH002JUS, BIOS N23ET66W (1.41 ) 09/02/2019 RIP: 0010:perf_trace_buf_alloc+0x8c/0xa0 Code: 80 3d 43 97 d0 01 00 74 07 31 c0 5b 5d 41 5c c3 ba 00 18 00 00 89 ee 48 c7 c7 00 82 7d 91 c6 05 25 97 d0 01 01 e8 22 ee bc 00 <0f> 0b 31 c0 eb db 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 55 89 RSP: 0018:ffffb922026b7d58 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff9da5ee012000 RCX: 0000000000000027 RDX: ffff9da881657828 RSI: 0000000000000001 RDI: ffff9da881657820 RBP: 00000000000019f4 R08: 0000000000000000 R09: ffffb922026b7b80 R10: ffffb922026b7b78 R11: ffffffff91dda688 R12: 000000000000000f R13: ffff9da5ee012108 R14: ffff9da8816570a0 R15: ffffb922026b7e30 FS: 00007f420db1a080(0000) GS:ffff9da881640000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000060 CR3: 00000002504a8006 CR4: 00000000003706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kprobe_perf_func+0x11e/0x270 ? do_execveat_common.isra.0+0x1/0x1c0 ? do_execveat_common.isra.0+0x5/0x1c0 kprobe_ftrace_handler+0x10e/0x1d0 0xffffffffc03aa0c8 ? do_execveat_common.isra.0+0x1/0x1c0 do_execveat_common.isra.0+0x5/0x1c0 __x64_sys_execve+0x33/0x40 do_syscall_64+0x6b/0xc0 ? do_syscall_64+0x11/0xc0 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f420dc1db37 Code: ff ff 76 e7 f7 d8 64 41 89 00 eb df 0f 1f 80 00 00 00 00 f7 d8 64 41 89 00 eb dc 0f 1f 84 00 00 00 00 00 b8 3b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 01 43 0f 00 f7 d8 64 89 01 48 RSP: 002b:00007ffd4e8b4e38 EFLAGS: 00000246 ORIG_RAX: 000000000000003b RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f420dc1db37 RDX: 0000564338d1e740 RSI: 0000564338d32d50 RDI: 0000564338d28f00 RBP: 0000564338d28f00 R08: 0000564338d32d50 R09: 0000000000000020 R10: 00000000000001b6 R11: 0000000000000246 R12: 0000564338d28f00 R13: 0000564338d32d50 R14: 0000564338d1e740 R15: 0000564338d28c60 ---[ end trace 83ab3e8e16275e49 ]--- ``` Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Robin H. Johnson <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-27tracing: Show size of requested perf bufferRobin H. Johnson1-1/+2
If the perf buffer isn't large enough, provide a hint about how large it needs to be for whatever is running. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Robin H. Johnson <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-27bootconfig: Initialize ret in xbc_parse_tree()Steven Rostedt (VMware)1-1/+1
The do while loop continues while ret is zero, but ret is never initialized. The check for ret in the loop at the while should always be initialized, but if an empty string were to be passed in, q would be NULL and p would be '\0', and it would break out of the loop without ever setting ret. Set ret to zero, and then xbc_verify_tree() would be called and catch that it is an empty tree and report the proper error. Link: https://lkml.kernel.org/r/[email protected] Fixes: bdac5c2b243f ("bootconfig: Allocate xbc_data inside xbc_init()") Reported-by: kernel test robot <[email protected]> Reported-by: Andrew Morton <[email protected]> Acked-by: Masami Hiramatsu <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-27ftrace: do CPU checking after preemption disabled王贇1-3/+3
With CONFIG_DEBUG_PREEMPT we observed reports like: BUG: using smp_processor_id() in preemptible caller is perf_ftrace_function_call+0x6f/0x2e0 CPU: 1 PID: 680 Comm: a.out Not tainted Call Trace: <TASK> dump_stack_lvl+0x8d/0xcf check_preemption_disabled+0x104/0x110 ? optimize_nops.isra.7+0x230/0x230 ? text_poke_bp_batch+0x9f/0x310 perf_ftrace_function_call+0x6f/0x2e0 ... __text_poke+0x5/0x620 text_poke_bp_batch+0x9f/0x310 This telling us the CPU could be changed after task is preempted, and the checking on CPU before preemption will be invalid. Since now ftrace_test_recursion_trylock() will help to disable the preemption, this patch just do the checking after trylock() to address the issue. Link: https://lkml.kernel.org/r/[email protected] CC: Steven Rostedt <[email protected]> Cc: Guo Ren <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: "James E.J. Bottomley" <[email protected]> Cc: Helge Deller <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Benjamin Herrenschmidt <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Paul Walmsley <[email protected]> Cc: Palmer Dabbelt <[email protected]> Cc: Albert Ou <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Jiri Kosina <[email protected]> Cc: Miroslav Benes <[email protected]> Cc: Petr Mladek <[email protected]> Cc: Joe Lawrence <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: "Peter Zijlstra (Intel)" <[email protected]> Cc: Nicholas Piggin <[email protected]> Cc: Jisheng Zhang <[email protected]> Reported-by: Abaci <[email protected]> Signed-off-by: Michael Wang <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-27ftrace: disable preemption when recursion locked王贇9-32/+21
As the documentation explained, ftrace_test_recursion_trylock() and ftrace_test_recursion_unlock() were supposed to disable and enable preemption properly, however currently this work is done outside of the function, which could be missing by mistake. And since the internal using of trace_test_and_set_recursion() and trace_clear_recursion() also require preemption disabled, we can just merge the logical. This patch will make sure the preemption has been disabled when trace_test_and_set_recursion() return bit >= 0, and trace_clear_recursion() will enable the preemption if previously enabled. Link: https://lkml.kernel.org/r/[email protected] CC: Petr Mladek <[email protected]> Cc: Guo Ren <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: "James E.J. Bottomley" <[email protected]> Cc: Helge Deller <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Benjamin Herrenschmidt <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Paul Walmsley <[email protected]> Cc: Palmer Dabbelt <[email protected]> Cc: Albert Ou <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Jiri Kosina <[email protected]> Cc: Joe Lawrence <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: Nicholas Piggin <[email protected]> Cc: Jisheng Zhang <[email protected]> CC: Steven Rostedt <[email protected]> CC: Miroslav Benes <[email protected]> Reported-by: Abaci <[email protected]> Suggested-by: Peter Zijlstra <[email protected]> Signed-off-by: Michael Wang <[email protected]> [ Removed extra line in comment - SDR ] Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-26tracing/histogram: Document expression arithmetic and constantsKalesh Singh1-0/+14
Histogram expressions now support division, and multiplication in addition to the already supported subtraction and addition operators. Numeric constants can also be used in a hist trigger expressions or assigned to a variable and used by refernce in an expression. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Kalesh Singh <[email protected]> Reviewed-by: Namhyung Kim <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-26tracing/histogram: Optimize division by a power of 2Kalesh Singh1-0/+4
The division is a slow operation. If the divisor is a power of 2, use a shift instead. Results were obtained using Android's version of perf (simpleperf[1]) as described below: 1. hist_field_div() is modified to call 2 test functions: test_hist_field_div_[not]_optimized(); passing them the same args. Use noinline and volatile to ensure these are not optimized out by the compiler. 2. Create a hist event trigger that uses division: events/kmem/rss_stat$ echo 'hist:keys=common_pid:x=size/<divisor>' >> trigger events/kmem/rss_stat$ echo 'hist:keys=common_pid:vals=$x' >> trigger 3. Run Android's lmkd_test[2] to generate rss_stat events, and record CPU samples with Android's simpleperf: simpleperf record -a --exclude-perf --post-unwind=yes -m 16384 -g -f 2000 -o perf.data == Results == Divisor is a power of 2 (divisor == 32): test_hist_field_div_not_optimized | 8,717,091 cpu-cycles test_hist_field_div_optimized | 1,643,137 cpu-cycles If the divisor is a power of 2, the optimized version is ~5.3x faster. Divisor is not a power of 2 (divisor == 33): test_hist_field_div_not_optimized | 4,444,324 cpu-cycles test_hist_field_div_optimized | 5,497,958 cpu-cycles If the divisor is not a power of 2, as expected, the optimized version is slightly slower (~24% slower). [1] https://android.googlesource.com/platform/system/extras/+/master/simpleperf/doc/README.md [2] https://cs.android.com/android/platform/superproject/+/master:system/memory/lmkd/tests/lmkd_test.cpp Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Kalesh Singh <[email protected]> Suggested-by: Steven Rostedt <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-26tracing/histogram: Covert expr to const if both operands are constantsKalesh Singh1-30/+74
If both operands of a hist trigger expression are constants, convert the expression to a constant. This optimization avoids having to perform the same calculation multiple times and also saves on memory since the merged constants are represented by a single struct hist_field instead or multiple. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Kalesh Singh <[email protected]> Suggested-by: Steven Rostedt <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-26tracing/histogram: Simplify handling of .sym-offset in expressionsKalesh Singh1-26/+17
The '-' in .sym-offset can confuse the hist trigger arithmetic expression parsing. Simplify the handling of this by replacing the 'sym-offset' with 'symXoffset'. This allows us to correctly evaluate expressions where the user may have inadvertently added a .sym-offset modifier to one of the operands in an expression, instead of bailing out. In this case the .sym-offset has no effect on the evaluation of the expression. The only valid use of the .sym-offset is as a hist key modifier. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Kalesh Singh <[email protected]> Suggested-by: Steven Rostedt <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-26tracing: Fix operator precedence for hist triggers expressionKalesh Singh1-70/+140
The current histogram expression evaluation logic evaluates the expression from right to left. This can lead to incorrect results if the operations are not associative (as is the case for subtraction and, the now added, division operators). e.g. 16-8-4-2 should be 2 not 10 --> 16-8-4-2 = ((16-8)-4)-2 64/8/4/2 should be 1 not 16 --> 64/8/4/2 = ((64/8)/4)/2 Division and multiplication are currently limited to single operation expression due to operator precedence support not yet implemented. Rework the expression parsing to support the correct evaluation of expressions containing operators of different precedences; and fix the associativity error by evaluating expressions with operators of the same precedence from left to right. Examples: (1) echo 'hist:keys=common_pid:a=8,b=4,c=2,d=1,w=$a-$b-$c-$d' \ >> event/trigger (2) echo 'hist:keys=common_pid:x=$a/$b/3/2' >> event/trigger (3) echo 'hist:keys=common_pid:y=$a+10/$c*1024' >> event/trigger (4) echo 'hist:keys=common_pid:z=$a/$b+$c*$d' >> event/trigger Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Kalesh Singh <[email protected]> Reviewed-by: Namhyung Kim <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-26tracing: Add division and multiplication support for hist triggersKalesh Singh1-1/+71
Adds basic support for division and multiplication operations for hist trigger variable expressions. For simplicity this patch only supports, division and multiplication for a single operation expression (e.g. x=$a/$b), as currently expressions are always evaluated right to left. This can lead to some incorrect results: e.g. echo 'hist:keys=common_pid:x=8-4-2' >> event/trigger 8-4-2 should evaluate to 2 i.e. (8-4)-2 but currently x evaluate to 6 i.e. 8-(4-2) Multiplication and division in sub-expressions will work correctly, once correct operator precedence support is added (See next patch in this series). For the undefined case of division by 0, the histogram expression evaluates to (u64)(-1). Since this cannot be detected when the expression is created, it is the responsibility of the user to be aware and account for this possibility. Examples: echo 'hist:keys=common_pid:a=8,b=4,x=$a/$b' \ >> event/trigger echo 'hist:keys=common_pid:y=5*$b' \ >> event/trigger Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Kalesh Singh <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-26tracing: Add support for creating hist trigger variables from literalKalesh Singh1-1/+70
Currently hist trigger expressions don't support the use of numeric literals: e.g. echo 'hist:keys=common_pid:x=$y-1234' --> is not valid expression syntax Having the ability to use numeric constants in hist triggers supports a wider range of expressions for creating variables. Add support for creating trace event histogram variables from numeric literals. e.g. echo 'hist:keys=common_pid:x=1234,y=size-1024' >> event/trigger A negative numeric constant is created, using unary minus operator (parentheses are required). e.g. echo 'hist:keys=common_pid:z=-(2)' >> event/trigger Constants can be used with division/multiplication (added in the next patch in this series) to implement granularity filters for frequent trace events. For instance we can limit emitting the rss_stat trace event to when there is a 512KB cross over in the rss size: # Create a synthetic event to monitor instead of the high frequency # rss_stat event echo 'rss_stat_throttled unsigned int mm_id; unsigned int curr; int member; long size' >> tracing/synthetic_events # Create a hist trigger that emits the synthetic rss_stat_throttled # event only when the rss size crosses a 512KB boundary. echo 'hist:keys=keys=mm_id,member:bucket=size/0x80000:onchange($bucket) .rss_stat_throttled(mm_id,curr,member,size)' >> events/kmem/rss_stat/trigger A use case for using constants with addition/subtraction is not yet known, but for completeness the use of constants are supported for all operators. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Kalesh Singh <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-26selftests/ftrace: Stop tracing while reading the trace file by defaultMasami Hiramatsu2-1/+13
Stop tracing while reading the trace file by default, to prevent the test results while checking it and to avoid taking a long time to check the result. If there is any testcase which wants to test the tracing while reading the trace file, please override this setting inside the test case. This also recovers the pause-on-trace when clean it up. Link: https://lkml.kernel.org/r/163529053143.690749.15365238954175942026.stgit@devnote2 Signed-off-by: Masami Hiramatsu <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-26MAINTAINERS: Update KPROBES and TRACING entriesTiezhu Yang1-1/+4
There is no git tree for KPROBES in MAINTAINERS, it is not convinent to rebase, lib/test_kprobes.c and samples/kprobes belong to kprobe, so add git tree and missing files for KPROBES, and also use linux-trace.git for TRACING to avoid confusing. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Tiezhu Yang <[email protected]> Acked-by: Masami Hiramatsu <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-26test_kprobes: Move it from kernel/ to lib/Tiezhu Yang3-1/+1
Since config KPROBES_SANITY_TEST is in lib/Kconfig.debug, it is better to let test_kprobes.c in lib/, just like other similar tests found in lib/. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Tiezhu Yang <[email protected]> Acked-by: Masami Hiramatsu <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-26docs, kprobes: Remove invalid URL and add new referenceTiezhu Yang1-1/+1
The following reference is invalid, remove it. https://www.ibm.com/developerworks/library/l-kprobes/index.html Add the following new reference "An introduction to KProbes": https://lwn.net/Articles/132196/ Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Tiezhu Yang <[email protected]> Acked-by: Masami Hiramatsu <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-26samples/kretprobes: Fix return value if register_kretprobe() failedTiezhu Yang1-1/+1
Use the actual return value instead of always -1 if register_kretprobe() failed. E.g. without this patch: # insmod samples/kprobes/kretprobe_example.ko func=no_such_func insmod: ERROR: could not insert module samples/kprobes/kretprobe_example.ko: Operation not permitted With this patch: # insmod samples/kprobes/kretprobe_example.ko func=no_such_func insmod: ERROR: could not insert module samples/kprobes/kretprobe_example.ko: Unknown symbol in module Link: https://lkml.kernel.org/r/[email protected] Fixes: 804defea1c02 ("Kprobes: move kprobe examples to samples/") Signed-off-by: Tiezhu Yang <[email protected]> Acked-by: Masami Hiramatsu <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-26lib/bootconfig: Fix the xbc_get_info kerneldocMasami Hiramatsu1-2/+2
Fix the kernel doc of xbc_get_info() to add '@' to the parameters. Link: https://lkml.kernel.org/r/163525086738.676803.15352231787913236933.stgit@devnote2 Fixes: e306220cb7b7 ("bootconfig: Add xbc_get_info() for the node information") Reported-by: Stephen Rothwell <[email protected]> Signed-off-by: Masami Hiramatsu <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-26kprobes: Add a test case for stacktrace from kretprobe handlerMasami Hiramatsu3-0/+171
Add a test case for stacktrace from kretprobe handler and nested kretprobe handlers. This test checks both of stack trace inside kretprobe handler and stack trace from pt_regs. Those stack trace must include actual function return address instead of kretprobe trampoline. The nested kretprobe stacktrace test checks whether the unwinder can correctly unwind the call frame on the stack which has been modified by the kretprobe. Since the stacktrace on kretprobe is correctly fixed only on x86, this introduces a meta kconfig ARCH_CORRECT_STACKTRACE_ON_KRETPROBE which tells user that the stacktrace on kretprobe is correct or not. The test results will be shown like below; TAP version 14 1..1 # Subtest: kprobes_test 1..6 ok 1 - test_kprobe ok 2 - test_kprobes ok 3 - test_kretprobe ok 4 - test_kretprobes ok 5 - test_stacktrace_on_kretprobe ok 6 - test_stacktrace_on_nested_kretprobe # kprobes_test: pass:6 fail:0 skip:0 total:6 # Totals: pass:6 fail:0 skip:0 total:6 ok 1 - kprobes_test Link: https://lkml.kernel.org/r/163516211244.604541.18350507860972214415.stgit@devnote2 Signed-off-by: Masami Hiramatsu <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-26lib/bootconfig: Make xbc_alloc_mem() and xbc_free_mem() as __init functionMasami Hiramatsu1-2/+2
Since the xbc_alloc_mem() and xbc_free_mem() are used from the __init functions and memblock_alloc() is __init function, make them __init functions too. Link: https://lkml.kernel.org/r/163515075747.547467.5746167540626712819.stgit@devnote2 Signed-off-by: Masami Hiramatsu <[email protected]> Fixes: 4ee1b4cac236 ("bootconfig: Cleanup dummy headers in tools/bootconfig") Reported-by: Stephen Rothwell <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-26ftrace/sh: Add arch_ftrace_ops_list_func stub to have compressed image still ↵Steven Rostedt (VMware)1-0/+3
link Using the linker script to fix an issue where some archs call the function tracer with just the ip (instruction pointer) and pip (parent instruction pointer) where as more up to date archs also pass in the associated ftrace_ops and the ftrace_regs pointer, the generic code will be called either with two parameters or four. To avoid any C undefined behavior of calling two parameters to four or four to two parameter function, two functions are created, where a preprocessor macro uses the one that matches the architecture. As the function pointers for them may be different, a typecast is used. But this triggers issues with newer compilers that will fail due to -Werror. A linker trick is now used to map the generic function to the function that is used (note the generic function is only used to set the default function callback). The linker trick defines ftrace_ops_list_func (the generic function) to arch_ftrace_ops_list_func (the arch defined one). Link: https://lore.kernel.org/all/[email protected]/ But this fails sh arch because their linker script is included in their compressed image that does not define arch_ftrace_ops_list_func at all sh4-linux-ld:arch/sh/boot/compressed/../../kernel/vmlinux.lds:32: undefined symbol `arch_ftrace_ops_list_func' referenced in expression Included a stub by that name in the misc.c to allow the code to compile and link, even though it's not used. This is similar to what was done for ftrace_stub: b83b43ffc6e4b ("fgraph: Fix function type mismatches of ftrace_graph_return using ftrace_stub") Link: https://lkml.kernel.org/r/[email protected] Cc: Yoshinori Sato <[email protected]> Cc: Rich Felker <[email protected]> Cc: [email protected] Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-26tracing/hwlat: Make some internal symbols staticWang ShaoBo1-2/+2
The sparse tool complains as follows: kernel/trace/trace_hwlat.c:82:27: warning: symbol 'hwlat_single_cpu_data' was not declared. Should it be static? kernel/trace/trace_hwlat.c:83:1: warning: symbol '__pcpu_scope_hwlat_per_cpu_data' was not declared. Should it be static? This symbol is not used outside of trace_hwlat.c, so this commit marks it static. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Wang ShaoBo <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-26tracing: Fix missing trace_boot_init_histograms kstrdup NULL checksMathieu Desnoyers1-0/+4
trace_boot_init_histograms misses NULL pointer checks for kstrdup failure. Link: https://lkml.kernel.org/r/[email protected] Fixes: 64dc7f6958ef5 ("tracing/boot: Show correct histogram error command") Acked-by: Masami Hiramatsu <[email protected]> Signed-off-by: Mathieu Desnoyers <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-25trace/timerlat: Add migrate-disabled field to the timerlat headerDaniel Bristot de Oliveira1-5/+6
Since "54357f0c9149 tracing: Add migrate-disabled counter to tracing output," the migrate disabled field is also printed in the !PREEMPR_RT kernel config. While this information was added to the vast majority of tracers, osnoise and timerlat were not updated (because they are new tracers). Fix timerlat header by adding the information about migrate disabled. Link: https://lkml.kernel.org/r/bc0c234ab49946cdd63effa6584e1d5e8662cb44.1634308385.git.bristot@kernel.org Cc: Daniel Bristot de Oliveira <[email protected]> Cc: Jonathan Corbet <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Sebastian Andrzej Siewior <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Fixes: 54357f0c9149 ("tracing: Add migrate-disabled counter to tracing output.") Signed-off-by: Daniel Bristot de Oliveira <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-25trace/osnoise: Add migrate-disabled field to the osnoise headerDaniel Bristot de Oliveira1-7/+7
Since "54357f0c9149 tracing: Add migrate-disabled counter to tracing output," the migrate disabled field is also printed in the !PREEMPR_RT kernel config. While this information was added to the vast majority of tracers, osnoise and timerlat were not updated (because they are new tracers). Fix osnoise header by adding the information about migrate disabled. Link: https://lkml.kernel.org/r/9cb3d54e29e0588dbba12e81486bd8a09adcd8ca.1634308385.git.bristot@kernel.org Cc: Daniel Bristot de Oliveira <[email protected]> Cc: Jonathan Corbet <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Sebastian Andrzej Siewior <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Fixes: 54357f0c9149 ("tracing: Add migrate-disabled counter to tracing output.") Signed-off-by: Daniel Bristot de Oliveira <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-25tracing/doc: Fix typos on the timerlat tracer documentationDaniel Bristot de Oliveira1-12/+12
Fixes a series of typos in the timerlat doc. Link: https://lkml.kernel.org/r/d3763eb376603890baab908141de6660ba18fff8.1634308385.git.bristot@kernel.org Cc: Daniel Bristot de Oliveira <[email protected]> Cc: Jonathan Corbet <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Sebastian Andrzej Siewior <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Fixes: a955d7eac177 ("trace: Add timerlat tracer") Signed-off-by: Daniel Bristot de Oliveira <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-25trace/osnoise: Fix an ifdef commentDaniel Bristot de Oliveira1-1/+1
s/CONFIG_OSNOISE_TRAECR/CONFIG_OSNOISE_TRACER/ No functional changes. Link: https://lkml.kernel.org/r/33924a16f6e5559ce24952ca7d62561604bfd94a.1634308385.git.bristot@kernel.org Cc: Daniel Bristot de Oliveira <[email protected]> Cc: Jonathan Corbet <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Sebastian Andrzej Siewior <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Signed-off-by: Daniel Bristot de Oliveira <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-25perf/core: allow ftrace for functions in kernel/event/core.cSong Liu1-5/+0
It is useful to trace functions in kernel/event/core.c. Allow ftrace for them by removing $(CC_FLAGS_FTRACE) from Makefile. Link: https://lkml.kernel.org/r/[email protected] Cc: Peter Zijlstra <[email protected]> Cc: Andrii Nakryiko <[email protected]> Cc: KP Singh <[email protected]> Signed-off-by: Song Liu <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-25tools/latency-collector: Use correct size when writing queue_full_warningViktor Rosendahl1-1/+1
queue_full_warning is a pointer, so it is wrong to use sizeof to calculate the number of characters of the string it points to. The effect is that we only print out the first few characters of the warning string. The correct way is to use strlen(). We don't need to add 1 to the strlen() because we don't want to write the terminating null character to stdout. Link: https://lkml.kernel.org/r/[email protected] Link: https://lore.kernel.org/r/8fd4bb65ef3da67feac9ce3258cdbe9824752cf1.1629198502.git.jing.yangyang@zte.com.cn Link: https://lore.kernel.org/r/[email protected] Reported-by: Zeal Robot <[email protected]> Signed-off-by: Viktor Rosendahl <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2021-10-25ftrace: Make ftrace_profile_pages_init staticchongjiapeng1-1/+1
This symbol is not used outside of ftrace.c, so marks it static. Fixes the following sparse warning: kernel/trace/ftrace.c:579:5: warning: symbol 'ftrace_profile_pages_init' was not declared. Should it be static? Link: https://lkml.kernel.org/r/1634640534-18280-1-git-send-email-jiapeng.chong@linux.alibaba.com Reported-by: Abaci Robot <[email protected]> Fixes: cafb168a1c92 ("tracing: make the function profiler per cpu") Signed-off-by: chongjiapeng <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>