From: Song Liu song@kernel.org
commit 5f4e5ce638e6a490b976ade4a40017b40abb2da0 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/events/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -838,7 +838,7 @@ static DEFINE_PER_CPU(struct list_head, */ 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;
@@ -849,7 +849,7 @@ static void perf_cgroup_switch(struct ta 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);