4.13-stable review patch. If anyone has any objections, please let me know.
------------------
From: Tejun Heo <t...@kernel.org>
commit be96b316deff35e119760982c43af74e606fa143 upstream.
The following commit:
864c2357ca89 ("perf/core: Do not set cpuctx->cgrp for unscheduled cgroups")
made list_update_cgroup_event() skip setting cpuctx->cgrp if no cgroup event
targets %current's cgroup.
This breaks perf_event's hierarchical support because events which target one
of the ancestors get ignored.
Fix it by using cgroup_is_descendant() test instead of equality.
Signed-off-by: Tejun Heo <t...@kernel.org>
Acked-by: Thomas Gleixner <t...@linutronix.de>
Cc: Arnaldo Carvalho de Melo <a...@kernel.org>
Cc: David Carrillo-Cisneros <davi...@google.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: kernel-t...@fb.com
Fixes: 864c2357ca89 ("perf/core: Do not set cpuctx->cgrp for unscheduled
cgroups")
Link:
http://lkml.kernel.org/r/20171028164237.ga972...@devbig577.frc2.facebook.com
Signed-off-by: Ingo Molnar <mi...@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
kernel/events/core.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -901,9 +901,11 @@ list_update_cgroup_event(struct perf_eve
cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
/* cpuctx->cgrp is NULL unless a cgroup event is active in this CPU .*/
if (add) {
+ struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
+
list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
- if (perf_cgroup_from_task(current, ctx) == event->cgrp)
- cpuctx->cgrp = event->cgrp;
+ if (cgroup_is_descendant(cgrp->css.cgroup,
event->cgrp->css.cgroup))
+ cpuctx->cgrp = cgrp;
} else {
list_del(cpuctx_entry);
cpuctx->cgrp = NULL;
