From: Tejun Heo Date: Sat, 28 Oct 2017 16:49:37 +0000 (-0700) Subject: perf/cgroup: Fix perf cgroup hierarchy support X-Git-Tag: Ubuntu-4.13.0-18.21~57 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=1986b1384414021c972db09dc7ba539d866341a6;p=mirror_ubuntu-artful-kernel.git perf/cgroup: Fix perf cgroup hierarchy support BugLink: http://bugs.launchpad.net/bugs/1731971 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 Acked-by: Thomas Gleixner Cc: Arnaldo Carvalho de Melo Cc: David Carrillo-Cisneros Cc: Linus Torvalds Cc: Peter Zijlstra Cc: kernel-team@fb.com Fixes: 864c2357ca89 ("perf/core: Do not set cpuctx->cgrp for unscheduled cgroups") Link: http://lkml.kernel.org/r/20171028164237.GA972780@devbig577.frc2.facebook.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman Signed-off-by: Stefan Bader Signed-off-by: Thadeu Lima de Souza Cascardo --- diff --git a/kernel/events/core.c b/kernel/events/core.c index 9ca98cb7d420..5d4398d1fa19 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -906,9 +906,11 @@ list_update_cgroup_event(struct perf_event *event, 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;