kevin/linux
1
Fork 0
Code

perf: Really fix event_function_call() locking

Browse Source 
Commit 558abc7e3f ("perf: Fix event_function_call() locking") lost
IRQ disabling by mistake.

Fixes: 558abc7e3f ("perf: Fix event_function_call() locking")
Reported-by: Pengfei Xu <pengfei.xu@intel.com>
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Tested-by: Pengfei Xu <pengfei.xu@intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
This commit is contained in:
Namhyung Kim 2024-08-13 22:55:11 +02:00 committed by Peter Zijlstra
parent 3e15a3fe3a
commit fe826cc265
1 changed files with 8 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
kernel/events/core.c
View File

@ -298,8 +298,8 @@ unlock:
static void event_function_call(struct perf_event *event, event_f func, void *data)
{
struct perf_event_context *ctx = event->ctx;
struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
struct perf_cpu_context *cpuctx;
struct event_function_struct efs = {
.event = event,
.func = func,
@ -327,22 +327,25 @@ again:
if (!task_function_call(task, event_function, &efs))
return;
local_irq_disable();
cpuctx = this_cpu_ptr(&perf_cpu_context);
perf_ctx_lock(cpuctx, ctx);
/*
* Reload the task pointer, it might have been changed by
* a concurrent perf_event_context_sched_out().
*/
task = ctx->task;
if (task == TASK_TOMBSTONE) {
perf_ctx_unlock(cpuctx, ctx);
return;
}
if (task == TASK_TOMBSTONE)
goto unlock;
if (ctx->is_active) {
perf_ctx_unlock(cpuctx, ctx);
local_irq_enable();
goto again;
}
func(event, NULL, ctx, data);
unlock:
perf_ctx_unlock(cpuctx, ctx);
local_irq_enable();
}
/*