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authorSong Liu <song@kernel.org>2022-02-03 16:40:57 -0800
committerPeter Zijlstra <peterz@infradead.org>2022-02-06 22:37:27 +0100
commit5f4e5ce638e6a490b976ade4a40017b40abb2da0 (patch)
treee1b716c4008595ffb28775f1357d8da88414befc /kernel
parent1d9093457b243061a9bba23543c38726e864a643 (diff)
perf: Fix list corruption in perf_cgroup_switch()
There's list corruption on cgrp_cpuctx_list. This happens on the following path: perf_cgroup_switch: list_for_each_entry(cgrp_cpuctx_list) cpu_ctx_sched_in ctx_sched_in ctx_pinned_sched_in merge_sched_in perf_cgroup_event_disable: remove the event from the list Use list_for_each_entry_safe() to allow removing an entry during iteration. Fixes: 058fe1c0440e ("perf/core: Make cgroup switch visit only cpuctxs with cgroup events") Signed-off-by: Song Liu <song@kernel.org> Reviewed-by: Rik van Riel <riel@surriel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20220204004057.2961252-1-song@kernel.org
Diffstat (limited to 'kernel')
-rw-r--r--kernel/events/core.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 57c7197838db..6859229497b1 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -839,7 +839,7 @@ static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
*/
static void perf_cgroup_switch(struct task_struct *task, int mode)
{
- struct perf_cpu_context *cpuctx;
+ struct perf_cpu_context *cpuctx, *tmp;
struct list_head *list;
unsigned long flags;
@@ -850,7 +850,7 @@ static void perf_cgroup_switch(struct task_struct *task, int mode)
local_irq_save(flags);
list = this_cpu_ptr(&cgrp_cpuctx_list);
- list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
+ list_for_each_entry_safe(cpuctx, tmp, list, cgrp_cpuctx_entry) {
WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
perf_ctx_lock(cpuctx, cpuctx->task_ctx);