Messages in this thread | | | Date | Fri, 23 Apr 2010 15:05:30 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [BUGFIX][PATCH] memcg rcu lock fix v3 |
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On Fri, 23 Apr 2010 14:10:32 +0800 Li Zefan <lizf@cn.fujitsu.com> wrote:
> > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> > > > > css_id() should be called under rcu_read_lock(). > > Following is a report from Li Zefan. > > == > > =================================================== > > [ INFO: suspicious rcu_dereference_check() usage. ] > > --------------------------------------------------- > > kernel/cgroup.c:4438 invoked rcu_dereference_check() without protection! > > > > other info that might help us debug this: > > > > > > rcu_scheduler_active = 1, debug_locks = 1 > > 1 lock held by kswapd0/31: > > #0: (swap_lock){+.+.-.}, at: [<c05058bb>] swap_info_get+0x4b/0xd0 > > > > stack backtrace: > ... > > > > And css_is_ancestor() should be called under rcu_read_lock(). > > > > > > Reported-by: Li Zefan <lizf@cn.fujitsu.com> > > Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> > > Cc: Balbir Singh <balbir@linux.vnet.ibm.com> > > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> > > With this patch applied, I did some more test, and no warning was triggered. > > Tested-by: Li Zefan <lizf@cn.fujitsu.com> > Thank you!.
-Kame
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