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Commit 68591e6f authored by Wei Wang's avatar Wei Wang Committed by Gerrit - the friendly Code Review server
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perf: Fix HW/SW event grouping failure 

In commit b05ec5a7 ("perf: Skip permission checks on kernel owned
perf events"), the patch changes the first argument of
find_get_context() from pmu to event. This leads to
group_leader != ctx so that hardware events and software
events can not be grouped together.

Bug: 30675453
Test: LTP syscalls-perf_event_open02 and set hwmon governor

CRs-Fixed: 2270895
Change-Id: I0b0021aab873f0886a7028a0a14637702b62b3d4
Git-repo: https://source.codeaurora.org/quic/la/kernel/common/


Git-commit: 03aba81b63d0c6c36bfa5a66b61956a1e480bd43
Signed-off-by: default avatarWei Wang <wvw@google.com>
Signed-off-by: default avatarChetan C R <cravin@codeaurora.org>
parent 9f52526c

kernel/events/core.c

+8 −6
Original line number Diff line number Diff line
@@ -3331,18 +3331,16 @@ errout: 
 * Returns a matching context with refcount and pincount.

 */

static struct perf_event_context *

find_get_context(struct perf_event *event, struct task_struct *task, int cpu)

find_get_context(struct pmu *pmu, struct task_struct *task, int cpu, bool check)

{

	struct perf_event_context *ctx, *clone_ctx = NULL;

	struct perf_cpu_context *cpuctx;

	struct pmu *pmu = event->pmu;

	unsigned long flags;

	int ctxn, err;



	if (!task) {

		/* Must be root to operate on a CPU event: */

		if (event->owner != EVENT_OWNER_KERNEL && perf_paranoid_cpu() &&

			!capable(CAP_SYS_ADMIN))

		if (check && perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))

			return ERR_PTR(-EACCES);



		/*
@@ -7614,7 +7612,7 @@ SYSCALL_DEFINE5(perf_event_open, 
	/*

	 * Get the target context (task or percpu):

	 */

	ctx = find_get_context(event, task, event->cpu);

	ctx = find_get_context(pmu, task, event->cpu, true);

	if (IS_ERR(ctx)) {

		err = PTR_ERR(ctx);

		goto err_alloc;
@@ -7811,8 +7809,12 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, 
	event->owner = EVENT_OWNER_KERNEL;



	account_event(event);

	/* Skip security check on kernel owned event */

	if (event->owner == EVENT_OWNER_KERNEL)

		ctx = find_get_context(event->pmu, task, cpu, false);

	else

		ctx = find_get_context(event->pmu, task, cpu, true);



	ctx = find_get_context(event, task, cpu);

	if (IS_ERR(ctx)) {

		err = PTR_ERR(ctx);

		goto err_free;