Messages in this thread | | | Date | Fri, 23 Apr 2010 14:10:32 +0800 | From | Li Zefan <> | Subject | Re: [BUGFIX][PATCH] memcg rcu lock fix v3 |
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> 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>
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