]> git.proxmox.com Git - mirror_ubuntu-hirsute-kernel.git/commit
percpu-refcount: init ->confirm_switch member properly
authorRoman Pen <roman.penyaev@profitbricks.com>
Thu, 11 Aug 2016 17:27:09 +0000 (19:27 +0200)
committerTejun Heo <tj@kernel.org>
Thu, 11 Aug 2016 17:52:23 +0000 (13:52 -0400)
commita67823c1ed1092160da94c31e6da5aeb35dca81c
tree7c0a2544991fddf233fc05158b61d2d9bd2927b2
parent33e465ce7cb30b71c113a26f36d293b545a28e12
percpu-refcount: init ->confirm_switch member properly

This patch targets two things which are related to ->confirm_switch:

 1. Init ->confirm_switch pointer with NULL on percpu_ref_init() or
    kernel frightfully complains with WARN_ON_ONCE(ref->confirm_switch)
    at __percpu_ref_switch_to_atomic if memory chunk was not properly
    zeroed.

 2. Warn if RCU callback is still in progress on percpu_ref_exit().
    The race still exists, because percpu_ref_call_confirm_rcu()
    drops ->confirm_switch to NULL early, but that is only a warning
    and still the caller is responsible that ref is no longer in
    active use.  Hopefully that can help to catch incorrect usage
    of percpu-refcount.

Signed-off-by: Roman Pen <roman.penyaev@profitbricks.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Tejun Heo <tj@kernel.org>
lib/percpu-refcount.c