[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-Id: <1447322404-10920-1-git-send-email-eranian@google.com>
Date: Thu, 12 Nov 2015 11:00:02 +0100
From: Stephane Eranian <eranian@...gle.com>
To: linux-kernel@...r.kernel.org
Cc: acme@...hat.com, peterz@...radead.org, mingo@...e.hu,
ak@...ux.intel.com, edumazet@...gle.com
Subject: [PATCH v3 0/2] perf/core: rcu fixes
This short patch series fixes some issues with RCU locking in the generic
perf layer.
Patch 1 fixes cgroup switching rcu issues related to the fact that
perf_cgroup_sched_out() and perf_cgroup_sched_in() were missing some
rcu read lock to protect the reference to the cgroup. Consequently,
we moved the rcu readlock out of perf_cgroup_switch() to avoid double
calls.
Patch 2 reinforces the testing for the rcu locking in perf cgorup code.
Either we have to hold the rcu read lock or we must have the ctx->lock
which guarantees the task cannot leave the cgroup.
Thanks to Peter and Eric from their suggestions on how to fix this correctly.
Stephane Eranian (2):
perf/core: fix RCU problem with cgroup context switching code
perf/core: robustify perf_cgroup_from_task rcu checks
arch/x86/kernel/cpu/perf_event_intel_cqm.c | 2 +-
include/linux/perf_event.h | 6 ++++--
kernel/events/core.c | 31 ++++++++++++++++++++----------
3 files changed, 26 insertions(+), 13 deletions(-)
--
2.5.0
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists