* [BUG] an RCU warning in memcg
@ 2010-04-23 3:00 Li Zefan
2010-04-23 3:14 ` [BUGFIX][PATCH] memcg rcu lock fix in swap code (Was " KAMEZAWA Hiroyuki
0 siblings, 1 reply; 17+ messages in thread
From: Li Zefan @ 2010-04-23 3:00 UTC (permalink / raw)
To: KAMEZAWA Hiroyuki, Balbir Singh, Daisuke Nishimura,
Paul E. McKenney
Cc: linux-mm@kvack.org, LKML
with CONFIG_PROVE_RCU=y, I saw this warning, it's because
css_id() is not under rcu_read_lock().
===================================================
[ 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:
Pid: 31, comm: kswapd0 Not tainted 2.6.34-rc5-tip+ #13
Call Trace:
[<c083c5d6>] ? printk+0x1d/0x1f
[<c0480744>] lockdep_rcu_dereference+0x94/0xb0
[<c049d6ed>] css_id+0x5d/0x60
[<c05165a5>] mem_cgroup_uncharge_swapcache+0x45/0xa0
[<c0505e4f>] swapcache_free+0x3f/0x60
[<c04e79e2>] __remove_mapping+0xb2/0xf0
[<c04e7cbb>] shrink_page_list+0x26b/0x490
[<c047f85d>] ? put_lock_stats+0xd/0x30
[<c083fd67>] ? _raw_spin_unlock_irq+0x27/0x50
[<c0482566>] ? trace_hardirqs_on_caller+0xb6/0x220
[<c04e8158>] shrink_inactive_list+0x278/0x620
[<c04729e1>] ? sched_clock_cpu+0x121/0x180
[<c047e9b8>] ? trace_hardirqs_off_caller+0x18/0x130
[<c047eadb>] ? trace_hardirqs_off+0xb/0x10
[<c0843438>] ? sub_preempt_count+0x8/0x90
[<c047f85d>] ? put_lock_stats+0xd/0x30
[<c04e8704>] shrink_zone+0x204/0x3c0
[<c083fcac>] ? _raw_spin_unlock+0x2c/0x50
[<c04e951e>] kswapd+0x61e/0x7c0
[<c04e6ed0>] ? isolate_pages_global+0x0/0x1f0
[<c046bae0>] ? autoremove_wake_function+0x0/0x50
[<c04e8f00>] ? kswapd+0x0/0x7c0
[<c046b5e4>] kthread+0x74/0x80
[<c046b570>] ? kthread+0x0/0x80
[<c04035ba>] kernel_thread_helper+0x6/0x10
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 17+ messages in thread* [BUGFIX][PATCH] memcg rcu lock fix in swap code (Was Re: [BUG] an RCU warning in memcg 2010-04-23 3:00 [BUG] an RCU warning in memcg Li Zefan @ 2010-04-23 3:14 ` KAMEZAWA Hiroyuki 2010-04-23 3:32 ` Balbir Singh 2010-04-23 3:49 ` Li Zefan 0 siblings, 2 replies; 17+ messages in thread From: KAMEZAWA Hiroyuki @ 2010-04-23 3:14 UTC (permalink / raw) To: Li Zefan Cc: Balbir Singh, Daisuke Nishimura, Paul E. McKenney, linux-mm@kvack.org, LKML, akpm@linux-foundation.org On Fri, 23 Apr 2010 11:00:41 +0800 Li Zefan <lizf@cn.fujitsu.com> wrote: > with CONFIG_PROVE_RCU=y, I saw this warning, it's because > css_id() is not under rcu_read_lock(). > Ok. Thank you for reporting. This is ok ? == 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: Pid: 31, comm: kswapd0 Not tainted 2.6.34-rc5-tip+ #13 Call Trace: [<c083c5d6>] ? printk+0x1d/0x1f [<c0480744>] lockdep_rcu_dereference+0x94/0xb0 [<c049d6ed>] css_id+0x5d/0x60 [<c05165a5>] mem_cgroup_uncharge_swapcache+0x45/0xa0 [<c0505e4f>] swapcache_free+0x3f/0x60 [<c04e79e2>] __remove_mapping+0xb2/0xf0 [<c04e7cbb>] shrink_page_list+0x26b/0x490 [<c047f85d>] ? put_lock_stats+0xd/0x30 [<c083fd67>] ? _raw_spin_unlock_irq+0x27/0x50 [<c0482566>] ? trace_hardirqs_on_caller+0xb6/0x220 [<c04e8158>] shrink_inactive_list+0x278/0x620 [<c04729e1>] ? sched_clock_cpu+0x121/0x180 [<c047e9b8>] ? trace_hardirqs_off_caller+0x18/0x130 [<c047eadb>] ? trace_hardirqs_off+0xb/0x10 [<c0843438>] ? sub_preempt_count+0x8/0x90 [<c047f85d>] ? put_lock_stats+0xd/0x30 [<c04e8704>] shrink_zone+0x204/0x3c0 [<c083fcac>] ? _raw_spin_unlock+0x2c/0x50 [<c04e951e>] kswapd+0x61e/0x7c0 [<c04e6ed0>] ? isolate_pages_global+0x0/0x1f0 [<c046bae0>] ? autoremove_wake_function+0x0/0x50 [<c04e8f00>] ? kswapd+0x0/0x7c0 [<c046b5e4>] kthread+0x74/0x80 [<c046b570>] ? kthread+0x0/0x80 [<c04035ba>] kernel_thread_helper+0x6/0x10 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> --- mm/memcontrol.c | 2 ++ 1 file changed, 2 insertions(+) Index: linux-2.6.34-rc5-mm1/mm/memcontrol.c =================================================================== --- linux-2.6.34-rc5-mm1.orig/mm/memcontrol.c +++ linux-2.6.34-rc5-mm1/mm/memcontrol.c @@ -2401,7 +2401,9 @@ mem_cgroup_uncharge_swapcache(struct pag /* record memcg information */ if (do_swap_account && swapout && memcg) { + rcu_read_lock(); swap_cgroup_record(ent, css_id(&memcg->css)); + rcu_read_unlock(); mem_cgroup_get(memcg); } if (swapout && memcg) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [BUGFIX][PATCH] memcg rcu lock fix in swap code (Was Re: [BUG] an RCU warning in memcg 2010-04-23 3:14 ` [BUGFIX][PATCH] memcg rcu lock fix in swap code (Was " KAMEZAWA Hiroyuki @ 2010-04-23 3:32 ` Balbir Singh 2010-04-23 3:49 ` Li Zefan 1 sibling, 0 replies; 17+ messages in thread From: Balbir Singh @ 2010-04-23 3:32 UTC (permalink / raw) To: KAMEZAWA Hiroyuki Cc: Li Zefan, Daisuke Nishimura, Paul E. McKenney, linux-mm@kvack.org, LKML, akpm@linux-foundation.org * KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> [2010-04-23 12:14:24]: > On Fri, 23 Apr 2010 11:00:41 +0800 > Li Zefan <lizf@cn.fujitsu.com> wrote: > > > with CONFIG_PROVE_RCU=y, I saw this warning, it's because > > css_id() is not under rcu_read_lock(). > > > > Ok. Thank you for reporting. > This is ok ? > == > 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: > Pid: 31, comm: kswapd0 Not tainted 2.6.34-rc5-tip+ #13 > Call Trace: > [<c083c5d6>] ? printk+0x1d/0x1f > [<c0480744>] lockdep_rcu_dereference+0x94/0xb0 > [<c049d6ed>] css_id+0x5d/0x60 > [<c05165a5>] mem_cgroup_uncharge_swapcache+0x45/0xa0 > [<c0505e4f>] swapcache_free+0x3f/0x60 > [<c04e79e2>] __remove_mapping+0xb2/0xf0 > [<c04e7cbb>] shrink_page_list+0x26b/0x490 > [<c047f85d>] ? put_lock_stats+0xd/0x30 > [<c083fd67>] ? _raw_spin_unlock_irq+0x27/0x50 > [<c0482566>] ? trace_hardirqs_on_caller+0xb6/0x220 > [<c04e8158>] shrink_inactive_list+0x278/0x620 > [<c04729e1>] ? sched_clock_cpu+0x121/0x180 > [<c047e9b8>] ? trace_hardirqs_off_caller+0x18/0x130 > [<c047eadb>] ? trace_hardirqs_off+0xb/0x10 > [<c0843438>] ? sub_preempt_count+0x8/0x90 > [<c047f85d>] ? put_lock_stats+0xd/0x30 > [<c04e8704>] shrink_zone+0x204/0x3c0 > [<c083fcac>] ? _raw_spin_unlock+0x2c/0x50 > [<c04e951e>] kswapd+0x61e/0x7c0 > [<c04e6ed0>] ? isolate_pages_global+0x0/0x1f0 > [<c046bae0>] ? autoremove_wake_function+0x0/0x50 > [<c04e8f00>] ? kswapd+0x0/0x7c0 > [<c046b5e4>] kthread+0x74/0x80 > [<c046b570>] ? kthread+0x0/0x80 > [<c04035ba>] kernel_thread_helper+0x6/0x10 > > 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> > --- > mm/memcontrol.c | 2 ++ > 1 file changed, 2 insertions(+) > > Index: linux-2.6.34-rc5-mm1/mm/memcontrol.c > =================================================================== > --- linux-2.6.34-rc5-mm1.orig/mm/memcontrol.c > +++ linux-2.6.34-rc5-mm1/mm/memcontrol.c > @@ -2401,7 +2401,9 @@ mem_cgroup_uncharge_swapcache(struct pag > > /* record memcg information */ > if (do_swap_account && swapout && memcg) { > + rcu_read_lock(); > swap_cgroup_record(ent, css_id(&memcg->css)); > + rcu_read_unlock(); > mem_cgroup_get(memcg); Excellent Catch! Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com> -- Three Cheers, Balbir -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [BUGFIX][PATCH] memcg rcu lock fix in swap code (Was Re: [BUG] an RCU warning in memcg 2010-04-23 3:14 ` [BUGFIX][PATCH] memcg rcu lock fix in swap code (Was " KAMEZAWA Hiroyuki 2010-04-23 3:32 ` Balbir Singh @ 2010-04-23 3:49 ` Li Zefan 2010-04-23 3:55 ` Li Zefan 1 sibling, 1 reply; 17+ messages in thread From: Li Zefan @ 2010-04-23 3:49 UTC (permalink / raw) To: KAMEZAWA Hiroyuki Cc: Balbir Singh, Daisuke Nishimura, Paul E. McKenney, linux-mm@kvack.org, LKML, akpm@linux-foundation.org KAMEZAWA Hiroyuki wrote: > On Fri, 23 Apr 2010 11:00:41 +0800 > Li Zefan <lizf@cn.fujitsu.com> wrote: > >> with CONFIG_PROVE_RCU=y, I saw this warning, it's because >> css_id() is not under rcu_read_lock(). >> > > Ok. Thank you for reporting. > This is ok ? Yes, and I did some more simple tests on memcg, no more warning showed up. > == > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [BUGFIX][PATCH] memcg rcu lock fix in swap code (Was Re: [BUG] an RCU warning in memcg 2010-04-23 3:49 ` Li Zefan @ 2010-04-23 3:55 ` Li Zefan 2010-04-23 3:50 ` KAMEZAWA Hiroyuki 2010-04-23 3:58 ` [BUGFIX][PATCH] memcg rcu lock fix v2 KAMEZAWA Hiroyuki 0 siblings, 2 replies; 17+ messages in thread From: Li Zefan @ 2010-04-23 3:55 UTC (permalink / raw) To: KAMEZAWA Hiroyuki Cc: Balbir Singh, Daisuke Nishimura, Paul E. McKenney, linux-mm@kvack.org, LKML, akpm@linux-foundation.org Li Zefan wrote: > KAMEZAWA Hiroyuki wrote: >> On Fri, 23 Apr 2010 11:00:41 +0800 >> Li Zefan <lizf@cn.fujitsu.com> wrote: >> >>> with CONFIG_PROVE_RCU=y, I saw this warning, it's because >>> css_id() is not under rcu_read_lock(). >>> >> Ok. Thank you for reporting. >> This is ok ? > > Yes, and I did some more simple tests on memcg, no more warning > showed up. > oops, after trigging oom, I saw 2 more warnings: =================================================== [ INFO: suspicious rcu_dereference_check() usage. ] --------------------------------------------------- kernel/cgroup.c:4459 invoked rcu_dereference_check() without protection! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 1 2 locks held by firefox/2258: #0: (&mm->mmap_sem){++++++}, at: [<c0843090>] do_page_fault+0x100/0x500 #1: (tasklist_lock){.?.?.-}, at: [<c04df1ac>] mem_cgroup_out_of_memory+0x2c/0x90 stack backtrace: Pid: 2258, comm: firefox Not tainted 2.6.34-rc5-tip+ #14 Call Trace: [<c083c636>] ? printk+0x1d/0x1f [<c0480744>] lockdep_rcu_dereference+0x94/0xb0 [<c049d61e>] css_is_ancestor+0xce/0xe0 [<c0517c41>] task_in_mem_cgroup+0xd1/0xf0 [<c0517b70>] ? task_in_mem_cgroup+0x0/0xf0 [<c04def10>] select_bad_process+0x70/0xe0 [<c04df1c1>] mem_cgroup_out_of_memory+0x41/0x90 [<c04826db>] ? trace_hardirqs_on+0xb/0x10 [<c05159e3>] mem_cgroup_handle_oom+0xf3/0x130 [<c046bae0>] ? autoremove_wake_function+0x0/0x50 [<c0516e01>] __mem_cgroup_try_charge+0x391/0x3d0 [<c047eadb>] ? trace_hardirqs_off+0xb/0x10 [<c05174c0>] mem_cgroup_charge_common+0x40/0x70 [<c0517620>] mem_cgroup_cache_charge+0x130/0x150 [<c04db6e7>] add_to_page_cache_locked+0x37/0x130 [<c04e5719>] ? __lru_cache_add+0x69/0xb0 [<c04db811>] add_to_page_cache_lru+0x31/0x80 [<c0549084>] mpage_readpages+0x84/0xf0 [<c057e4d0>] ? ext3_get_block+0x0/0x110 [<c057c760>] ? ext3_readpages+0x0/0x20 [<c057c77e>] ext3_readpages+0x1e/0x20 [<c057e4d0>] ? ext3_get_block+0x0/0x110 [<c04e4889>] __do_page_cache_readahead+0x219/0x2b0 [<c04e4748>] ? __do_page_cache_readahead+0xd8/0x2b0 [<c04e4946>] ra_submit+0x26/0x30 [<c04dcf86>] filemap_fault+0x436/0x470 [<c04f6a95>] __do_fault+0x55/0x550 [<c04f7afb>] handle_mm_fault+0x17b/0xad0 [<c0843090>] ? do_page_fault+0x100/0x500 [<c0842f90>] ? do_page_fault+0x0/0x500 [<c0843109>] do_page_fault+0x179/0x500 [<c04532b1>] ? __do_softirq+0x111/0x260 [<c045344f>] ? do_softirq+0x4f/0x70 [<c047ea65>] ? trace_hardirqs_off_caller+0xc5/0x130 [<c0840b0f>] ? error_code+0x67/0x70 [<c047ea14>] ? trace_hardirqs_off_caller+0x74/0x130 [<c0842f90>] ? do_page_fault+0x0/0x500 [<c0840b13>] error_code+0x6b/0x70 [<c0840000>] ? _raw_read_trylock+0x40/0x90 [<c0842f90>] ? do_page_fault+0x0/0x500 =================================================== [ INFO: suspicious rcu_dereference_check() usage. ] --------------------------------------------------- kernel/cgroup.c:4460 invoked rcu_dereference_check() without protection! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 1 2 locks held by firefox/2258: #0: (&mm->mmap_sem){++++++}, at: [<c0843090>] do_page_fault+0x100/0x500 #1: (tasklist_lock){.?.?.-}, at: [<c04df1ac>] mem_cgroup_out_of_memory+0x2c/0x90 stack backtrace: Pid: 2258, comm: firefox Not tainted 2.6.34-rc5-tip+ #14 Call Trace: [<c083c636>] ? printk+0x1d/0x1f [<c0480744>] lockdep_rcu_dereference+0x94/0xb0 [<c049d5e6>] css_is_ancestor+0x96/0xe0 [<c0517c41>] task_in_mem_cgroup+0xd1/0xf0 [<c0517b70>] ? task_in_mem_cgroup+0x0/0xf0 [<c04def10>] select_bad_process+0x70/0xe0 [<c04df1c1>] mem_cgroup_out_of_memory+0x41/0x90 [<c04826db>] ? trace_hardirqs_on+0xb/0x10 [<c05159e3>] mem_cgroup_handle_oom+0xf3/0x130 [<c046bae0>] ? autoremove_wake_function+0x0/0x50 [<c0516e01>] __mem_cgroup_try_charge+0x391/0x3d0 [<c047eadb>] ? trace_hardirqs_off+0xb/0x10 [<c05174c0>] mem_cgroup_charge_common+0x40/0x70 [<c0517620>] mem_cgroup_cache_charge+0x130/0x150 [<c04db6e7>] add_to_page_cache_locked+0x37/0x130 [<c04e5719>] ? __lru_cache_add+0x69/0xb0 [<c04db811>] add_to_page_cache_lru+0x31/0x80 [<c0549084>] mpage_readpages+0x84/0xf0 [<c057e4d0>] ? ext3_get_block+0x0/0x110 [<c057c760>] ? ext3_readpages+0x0/0x20 [<c057c77e>] ext3_readpages+0x1e/0x20 [<c057e4d0>] ? ext3_get_block+0x0/0x110 [<c04e4889>] __do_page_cache_readahead+0x219/0x2b0 [<c04e4748>] ? __do_page_cache_readahead+0xd8/0x2b0 [<c04e4946>] ra_submit+0x26/0x30 [<c04dcf86>] filemap_fault+0x436/0x470 [<c04f6a95>] __do_fault+0x55/0x550 [<c04f7afb>] handle_mm_fault+0x17b/0xad0 [<c0843090>] ? do_page_fault+0x100/0x500 [<c0842f90>] ? do_page_fault+0x0/0x500 [<c0843109>] do_page_fault+0x179/0x500 [<c04532b1>] ? __do_softirq+0x111/0x260 [<c045344f>] ? do_softirq+0x4f/0x70 [<c047ea65>] ? trace_hardirqs_off_caller+0xc5/0x130 [<c0840b0f>] ? error_code+0x67/0x70 [<c047ea14>] ? trace_hardirqs_off_caller+0x74/0x130 [<c0842f90>] ? do_page_fault+0x0/0x500 [<c0840b13>] error_code+0x6b/0x70 [<c0840000>] ? _raw_read_trylock+0x40/0x90 [<c0842f90>] ? do_page_fault+0x0/0x500 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [BUGFIX][PATCH] memcg rcu lock fix in swap code (Was Re: [BUG] an RCU warning in memcg 2010-04-23 3:55 ` Li Zefan @ 2010-04-23 3:50 ` KAMEZAWA Hiroyuki 2010-04-23 4:02 ` Li Zefan 2010-04-23 3:58 ` [BUGFIX][PATCH] memcg rcu lock fix v2 KAMEZAWA Hiroyuki 1 sibling, 1 reply; 17+ messages in thread From: KAMEZAWA Hiroyuki @ 2010-04-23 3:50 UTC (permalink / raw) To: Li Zefan Cc: Balbir Singh, Daisuke Nishimura, Paul E. McKenney, linux-mm@kvack.org, LKML, akpm@linux-foundation.org On Fri, 23 Apr 2010 11:55:16 +0800 Li Zefan <lizf@cn.fujitsu.com> wrote: > Li Zefan wrote: > > KAMEZAWA Hiroyuki wrote: > >> On Fri, 23 Apr 2010 11:00:41 +0800 > >> Li Zefan <lizf@cn.fujitsu.com> wrote: > >> > >>> with CONFIG_PROVE_RCU=y, I saw this warning, it's because > >>> css_id() is not under rcu_read_lock(). > >>> > >> Ok. Thank you for reporting. > >> This is ok ? > > > > Yes, and I did some more simple tests on memcg, no more warning > > showed up. > > > > oops, after trigging oom, I saw 2 more warnings: > ok, I will update. thank you. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [BUGFIX][PATCH] memcg rcu lock fix in swap code (Was Re: [BUG] an RCU warning in memcg 2010-04-23 3:50 ` KAMEZAWA Hiroyuki @ 2010-04-23 4:02 ` Li Zefan 0 siblings, 0 replies; 17+ messages in thread From: Li Zefan @ 2010-04-23 4:02 UTC (permalink / raw) To: KAMEZAWA Hiroyuki Cc: Balbir Singh, Daisuke Nishimura, Paul E. McKenney, linux-mm@kvack.org, LKML, akpm@linux-foundation.org KAMEZAWA Hiroyuki wrote: > On Fri, 23 Apr 2010 11:55:16 +0800 > Li Zefan <lizf@cn.fujitsu.com> wrote: > >> Li Zefan wrote: >>> KAMEZAWA Hiroyuki wrote: >>>> On Fri, 23 Apr 2010 11:00:41 +0800 >>>> Li Zefan <lizf@cn.fujitsu.com> wrote: >>>> >>>>> with CONFIG_PROVE_RCU=y, I saw this warning, it's because >>>>> css_id() is not under rcu_read_lock(). >>>>> >>>> Ok. Thank you for reporting. >>>> This is ok ? >>> Yes, and I did some more simple tests on memcg, no more warning >>> showed up. >>> >> oops, after trigging oom, I saw 2 more warnings: >> > > ok, I will update. thank you. > one more: =================================================== [ 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 3 locks held by bash/2270: #0: (cgroup_mutex){+.+.+.}, at: [<c049ab37>] cgroup_lock_live_group+0x17/0x30 #1: (&mm->mmap_sem){++++++}, at: [<c0517302>] mem_cgroup_can_attach+0xb2/0x130 #2: (&(&mm->page_table_lock)->rlock){+.+.-.}, at: [<c0513c23>] mem_cgroup_count_precharge_pte_range+0x93/0x130 stack backtrace: Pid: 2270, comm: bash Not tainted 2.6.34-rc5-tip+ #14 Call Trace: [<c083c636>] ? printk+0x1d/0x1f [<c0480744>] lockdep_rcu_dereference+0x94/0xb0 [<c049d6ed>] css_id+0x5d/0x60 [<c051373f>] is_target_pte_for_mc+0x16f/0x1c0 [<c083f46b>] ? _raw_spin_lock+0x6b/0x80 [<c0513c4d>] mem_cgroup_count_precharge_pte_range+0xbd/0x130 [<c0513b90>] ? mem_cgroup_count_precharge_pte_range+0x0/0x130 [<c05030bd>] walk_page_range+0x25d/0x3f0 [<c0517344>] mem_cgroup_can_attach+0xf4/0x130 [<c0513b90>] ? mem_cgroup_count_precharge_pte_range+0x0/0x130 [<c0517250>] ? mem_cgroup_can_attach+0x0/0x130 [<c049e000>] cgroup_attach_task+0x70/0x280 [<c049e633>] cgroup_tasks_write+0x63/0x1c0 [<c049e660>] ? cgroup_tasks_write+0x90/0x1c0 [<c049d515>] cgroup_file_write+0x1f5/0x230 [<c0842f90>] ? do_page_fault+0x0/0x500 [<c047107b>] ? up_read+0x1b/0x30 [<c0843195>] ? do_page_fault+0x205/0x500 [<c051a8c4>] vfs_write+0xa4/0x1a0 [<c049d320>] ? cgroup_file_write+0x0/0x230 [<c051b3f6>] sys_write+0x46/0x70 [<c0403090>] sysenter_do_call+0x12/0x36 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 17+ messages in thread
* [BUGFIX][PATCH] memcg rcu lock fix v2 2010-04-23 3:55 ` Li Zefan 2010-04-23 3:50 ` KAMEZAWA Hiroyuki @ 2010-04-23 3:58 ` KAMEZAWA Hiroyuki 2010-04-23 4:03 ` [BUGFIX][PATCH] memcg rcu lock fix v3 KAMEZAWA Hiroyuki 1 sibling, 1 reply; 17+ messages in thread From: KAMEZAWA Hiroyuki @ 2010-04-23 3:58 UTC (permalink / raw) To: Li Zefan Cc: Balbir Singh, Daisuke Nishimura, Paul E. McKenney, linux-mm@kvack.org, LKML, akpm@linux-foundation.org On Fri, 23 Apr 2010 11:55:16 +0800 Li Zefan <lizf@cn.fujitsu.com> wrote: > Li Zefan wrote: > > KAMEZAWA Hiroyuki wrote: > >> On Fri, 23 Apr 2010 11:00:41 +0800 > >> Li Zefan <lizf@cn.fujitsu.com> wrote: > >> > >>> with CONFIG_PROVE_RCU=y, I saw this warning, it's because > >>> css_id() is not under rcu_read_lock(). > >>> > >> Ok. Thank you for reporting. > >> This is ok ? > > > > Yes, and I did some more simple tests on memcg, no more warning > > showed up. > > > > oops, after trigging oom, I saw 2 more warnings: > Thank you for good testing. = From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> css_id() should be called under rcu_read_lock(). And css_is_ancestor() 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: Pid: 31, comm: kswapd0 Not tainted 2.6.34-rc5-tip+ #13 Call Trace: [<c083c5d6>] ? printk+0x1d/0x1f [<c0480744>] lockdep_rcu_dereference+0x94/0xb0 [<c049d6ed>] css_id+0x5d/0x60 [<c05165a5>] mem_cgroup_uncharge_swapcache+0x45/0xa0 [<c0505e4f>] swapcache_free+0x3f/0x60 [<c04e79e2>] __remove_mapping+0xb2/0xf0 [<c04e7cbb>] shrink_page_list+0x26b/0x490 [<c047f85d>] ? put_lock_stats+0xd/0x30 [<c083fd67>] ? _raw_spin_unlock_irq+0x27/0x50 [<c0482566>] ? trace_hardirqs_on_caller+0xb6/0x220 [<c04e8158>] shrink_inactive_list+0x278/0x620 [<c04729e1>] ? sched_clock_cpu+0x121/0x180 [<c047e9b8>] ? trace_hardirqs_off_caller+0x18/0x130 [<c047eadb>] ? trace_hardirqs_off+0xb/0x10 [<c0843438>] ? sub_preempt_count+0x8/0x90 [<c047f85d>] ? put_lock_stats+0xd/0x30 [<c04e8704>] shrink_zone+0x204/0x3c0 [<c083fcac>] ? _raw_spin_unlock+0x2c/0x50 [<c04e951e>] kswapd+0x61e/0x7c0 [<c04e6ed0>] ? isolate_pages_global+0x0/0x1f0 [<c046bae0>] ? autoremove_wake_function+0x0/0x50 [<c04e8f00>] ? kswapd+0x0/0x7c0 [<c046b5e4>] kthread+0x74/0x80 [<c046b570>] ? kthread+0x0/0x80 [<c04035ba>] kernel_thread_helper+0x6/0x10 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> --- mm/memcontrol.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) Index: linux-2.6.34-rc5-mm1/mm/memcontrol.c =================================================================== --- linux-2.6.34-rc5-mm1.orig/mm/memcontrol.c +++ linux-2.6.34-rc5-mm1/mm/memcontrol.c @@ -838,10 +838,12 @@ int task_in_mem_cgroup(struct task_struc * enabled in "curr" and "curr" is a child of "mem" in *cgroup* * hierarchy(even if use_hierarchy is disabled in "mem"). */ + rcu_read_lock(); if (mem->use_hierarchy) ret = css_is_ancestor(&curr->css, &mem->css); else ret = (curr == mem); + rcu_read_unlock(); css_put(&curr->css); return ret; } @@ -1360,9 +1362,13 @@ static int memcg_oom_wake_function(wait_ * Both of oom_wait_info->mem and wake_mem are stable under us. * Then we can use css_is_ancestor without taking care of RCU. */ + rcu_read_lock(); if (!css_is_ancestor(&oom_wait_info->mem->css, &wake_mem->css) && - !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css)) + !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css)) { + rcu_read_unlock(); return 0; + } + rcu_read_unlock(); wakeup: return autoremove_wake_function(wait, mode, sync, arg); @@ -2401,7 +2407,9 @@ mem_cgroup_uncharge_swapcache(struct pag /* record memcg information */ if (do_swap_account && swapout && memcg) { + rcu_read_lock(); swap_cgroup_record(ent, css_id(&memcg->css)); + rcu_read_unlock(); mem_cgroup_get(memcg); } if (swapout && memcg) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 17+ messages in thread
* [BUGFIX][PATCH] memcg rcu lock fix v3 2010-04-23 3:58 ` [BUGFIX][PATCH] memcg rcu lock fix v2 KAMEZAWA Hiroyuki @ 2010-04-23 4:03 ` KAMEZAWA Hiroyuki 2010-04-23 4:41 ` Daisuke Nishimura ` (3 more replies) 0 siblings, 4 replies; 17+ messages in thread From: KAMEZAWA Hiroyuki @ 2010-04-23 4:03 UTC (permalink / raw) To: KAMEZAWA Hiroyuki Cc: Li Zefan, Balbir Singh, Daisuke Nishimura, Paul E. McKenney, linux-mm@kvack.org, LKML, akpm@linux-foundation.org On Fri, 23 Apr 2010 12:58:14 +0900 KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote: > On Fri, 23 Apr 2010 11:55:16 +0800 > Li Zefan <lizf@cn.fujitsu.com> wrote: > > > Li Zefan wrote: > > > KAMEZAWA Hiroyuki wrote: > > >> On Fri, 23 Apr 2010 11:00:41 +0800 > > >> Li Zefan <lizf@cn.fujitsu.com> wrote: > > >> > > >>> with CONFIG_PROVE_RCU=y, I saw this warning, it's because > > >>> css_id() is not under rcu_read_lock(). > > >>> > > >> Ok. Thank you for reporting. > > >> This is ok ? > > > > > > Yes, and I did some more simple tests on memcg, no more warning > > > showed up. > > > > > > > oops, after trigging oom, I saw 2 more warnings: > > > > Thank you for good testing. v3 here...sorry too rapid posting... == 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: Pid: 31, comm: kswapd0 Not tainted 2.6.34-rc5-tip+ #13 Call Trace: [<c083c5d6>] ? printk+0x1d/0x1f [<c0480744>] lockdep_rcu_dereference+0x94/0xb0 [<c049d6ed>] css_id+0x5d/0x60 [<c05165a5>] mem_cgroup_uncharge_swapcache+0x45/0xa0 [<c0505e4f>] swapcache_free+0x3f/0x60 [<c04e79e2>] __remove_mapping+0xb2/0xf0 [<c04e7cbb>] shrink_page_list+0x26b/0x490 [<c047f85d>] ? put_lock_stats+0xd/0x30 [<c083fd67>] ? _raw_spin_unlock_irq+0x27/0x50 [<c0482566>] ? trace_hardirqs_on_caller+0xb6/0x220 [<c04e8158>] shrink_inactive_list+0x278/0x620 [<c04729e1>] ? sched_clock_cpu+0x121/0x180 [<c047e9b8>] ? trace_hardirqs_off_caller+0x18/0x130 [<c047eadb>] ? trace_hardirqs_off+0xb/0x10 [<c0843438>] ? sub_preempt_count+0x8/0x90 [<c047f85d>] ? put_lock_stats+0xd/0x30 [<c04e8704>] shrink_zone+0x204/0x3c0 [<c083fcac>] ? _raw_spin_unlock+0x2c/0x50 [<c04e951e>] kswapd+0x61e/0x7c0 [<c04e6ed0>] ? isolate_pages_global+0x0/0x1f0 [<c046bae0>] ? autoremove_wake_function+0x0/0x50 [<c04e8f00>] ? kswapd+0x0/0x7c0 [<c046b5e4>] kthread+0x74/0x80 [<c046b570>] ? kthread+0x0/0x80 [<c04035ba>] kernel_thread_helper+0x6/0x10 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> --- mm/memcontrol.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) Index: linux-2.6.34-rc5-mm1/mm/memcontrol.c =================================================================== --- linux-2.6.34-rc5-mm1.orig/mm/memcontrol.c +++ linux-2.6.34-rc5-mm1/mm/memcontrol.c @@ -838,10 +838,12 @@ int task_in_mem_cgroup(struct task_struc * enabled in "curr" and "curr" is a child of "mem" in *cgroup* * hierarchy(even if use_hierarchy is disabled in "mem"). */ + rcu_read_lock(); if (mem->use_hierarchy) ret = css_is_ancestor(&curr->css, &mem->css); else ret = (curr == mem); + rcu_read_unlock(); css_put(&curr->css); return ret; } @@ -1360,9 +1362,13 @@ static int memcg_oom_wake_function(wait_ * Both of oom_wait_info->mem and wake_mem are stable under us. * Then we can use css_is_ancestor without taking care of RCU. */ + rcu_read_lock(); if (!css_is_ancestor(&oom_wait_info->mem->css, &wake_mem->css) && - !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css)) + !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css)) { + rcu_read_unlock(); return 0; + } + rcu_read_unlock(); wakeup: return autoremove_wake_function(wait, mode, sync, arg); @@ -2401,7 +2407,9 @@ mem_cgroup_uncharge_swapcache(struct pag /* record memcg information */ if (do_swap_account && swapout && memcg) { + rcu_read_lock(); swap_cgroup_record(ent, css_id(&memcg->css)); + rcu_read_unlock(); mem_cgroup_get(memcg); } if (swapout && memcg) @@ -2458,8 +2466,10 @@ static int mem_cgroup_move_swap_account( { unsigned short old_id, new_id; + rcu_read_lock(); old_id = css_id(&from->css); new_id = css_id(&to->css); + rcu_read_unlock(); if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { mem_cgroup_swap_statistics(from, false); @@ -4303,7 +4313,11 @@ static int is_target_pte_for_mc(struct v } /* Threre is a swap entry and a page doesn't exist or isn't charged */ if (ent.val && !ret) { - if (css_id(&mc.from->css) == lookup_swap_cgroup(ent)) { + unsigned short id; + rcu_read_lock(); + id = css_id(&mc.from->css); + rcu_read_unlock(); + if (id == lookup_swap_cgroup(ent)) { ret = MC_TARGET_SWAP; if (target) target->ent = ent; -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [BUGFIX][PATCH] memcg rcu lock fix v3 2010-04-23 4:03 ` [BUGFIX][PATCH] memcg rcu lock fix v3 KAMEZAWA Hiroyuki @ 2010-04-23 4:41 ` Daisuke Nishimura 2010-04-23 6:10 ` Li Zefan ` (2 subsequent siblings) 3 siblings, 0 replies; 17+ messages in thread From: Daisuke Nishimura @ 2010-04-23 4:41 UTC (permalink / raw) To: KAMEZAWA Hiroyuki, Li Zefan Cc: Balbir Singh, Paul E. McKenney, linux-mm@kvack.org, LKML, akpm@linux-foundation.org, Daisuke Nishimura On Fri, 23 Apr 2010 13:03:49 +0900, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote: > On Fri, 23 Apr 2010 12:58:14 +0900 > KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote: > > > On Fri, 23 Apr 2010 11:55:16 +0800 > > Li Zefan <lizf@cn.fujitsu.com> wrote: > > > > > Li Zefan wrote: > > > > KAMEZAWA Hiroyuki wrote: > > > >> On Fri, 23 Apr 2010 11:00:41 +0800 > > > >> Li Zefan <lizf@cn.fujitsu.com> wrote: > > > >> > > > >>> with CONFIG_PROVE_RCU=y, I saw this warning, it's because > > > >>> css_id() is not under rcu_read_lock(). > > > >>> > > > >> Ok. Thank you for reporting. > > > >> This is ok ? > > > > > > > > Yes, and I did some more simple tests on memcg, no more warning > > > > showed up. > > > > > > > > > > oops, after trigging oom, I saw 2 more warnings: > > > > > > > Thank you for good testing. > v3 here...sorry too rapid posting... > Thank you for your report & patch. (and I'm sorry that I've not been active these days ;( ) This patch looks good to me and, IIUC, would be enough to fix this bug. Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> BTW, it wouldn't cause any problem, I think former rcu_read_lock()/unlock() in task_in_mem_cgroup() is unnecessary, because try_get_mem_cgroup_from_mm() calls them for itself. Thanks, Daisuke Nishimura. > == > 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: > Pid: 31, comm: kswapd0 Not tainted 2.6.34-rc5-tip+ #13 > Call Trace: > [<c083c5d6>] ? printk+0x1d/0x1f > [<c0480744>] lockdep_rcu_dereference+0x94/0xb0 > [<c049d6ed>] css_id+0x5d/0x60 > [<c05165a5>] mem_cgroup_uncharge_swapcache+0x45/0xa0 > [<c0505e4f>] swapcache_free+0x3f/0x60 > [<c04e79e2>] __remove_mapping+0xb2/0xf0 > [<c04e7cbb>] shrink_page_list+0x26b/0x490 > [<c047f85d>] ? put_lock_stats+0xd/0x30 > [<c083fd67>] ? _raw_spin_unlock_irq+0x27/0x50 > [<c0482566>] ? trace_hardirqs_on_caller+0xb6/0x220 > [<c04e8158>] shrink_inactive_list+0x278/0x620 > [<c04729e1>] ? sched_clock_cpu+0x121/0x180 > [<c047e9b8>] ? trace_hardirqs_off_caller+0x18/0x130 > [<c047eadb>] ? trace_hardirqs_off+0xb/0x10 > [<c0843438>] ? sub_preempt_count+0x8/0x90 > [<c047f85d>] ? put_lock_stats+0xd/0x30 > [<c04e8704>] shrink_zone+0x204/0x3c0 > [<c083fcac>] ? _raw_spin_unlock+0x2c/0x50 > [<c04e951e>] kswapd+0x61e/0x7c0 > [<c04e6ed0>] ? isolate_pages_global+0x0/0x1f0 > [<c046bae0>] ? autoremove_wake_function+0x0/0x50 > [<c04e8f00>] ? kswapd+0x0/0x7c0 > [<c046b5e4>] kthread+0x74/0x80 > [<c046b570>] ? kthread+0x0/0x80 > [<c04035ba>] kernel_thread_helper+0x6/0x10 > > 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> > --- > mm/memcontrol.c | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > Index: linux-2.6.34-rc5-mm1/mm/memcontrol.c > =================================================================== > --- linux-2.6.34-rc5-mm1.orig/mm/memcontrol.c > +++ linux-2.6.34-rc5-mm1/mm/memcontrol.c > @@ -838,10 +838,12 @@ int task_in_mem_cgroup(struct task_struc > * enabled in "curr" and "curr" is a child of "mem" in *cgroup* > * hierarchy(even if use_hierarchy is disabled in "mem"). > */ > + rcu_read_lock(); > if (mem->use_hierarchy) > ret = css_is_ancestor(&curr->css, &mem->css); > else > ret = (curr == mem); > + rcu_read_unlock(); > css_put(&curr->css); > return ret; > } > @@ -1360,9 +1362,13 @@ static int memcg_oom_wake_function(wait_ > * Both of oom_wait_info->mem and wake_mem are stable under us. > * Then we can use css_is_ancestor without taking care of RCU. > */ > + rcu_read_lock(); > if (!css_is_ancestor(&oom_wait_info->mem->css, &wake_mem->css) && > - !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css)) > + !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css)) { > + rcu_read_unlock(); > return 0; > + } > + rcu_read_unlock(); > > wakeup: > return autoremove_wake_function(wait, mode, sync, arg); > @@ -2401,7 +2407,9 @@ mem_cgroup_uncharge_swapcache(struct pag > > /* record memcg information */ > if (do_swap_account && swapout && memcg) { > + rcu_read_lock(); > swap_cgroup_record(ent, css_id(&memcg->css)); > + rcu_read_unlock(); > mem_cgroup_get(memcg); > } > if (swapout && memcg) > @@ -2458,8 +2466,10 @@ static int mem_cgroup_move_swap_account( > { > unsigned short old_id, new_id; > > + rcu_read_lock(); > old_id = css_id(&from->css); > new_id = css_id(&to->css); > + rcu_read_unlock(); > > if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { > mem_cgroup_swap_statistics(from, false); > @@ -4303,7 +4313,11 @@ static int is_target_pte_for_mc(struct v > } > /* Threre is a swap entry and a page doesn't exist or isn't charged */ > if (ent.val && !ret) { > - if (css_id(&mc.from->css) == lookup_swap_cgroup(ent)) { > + unsigned short id; > + rcu_read_lock(); > + id = css_id(&mc.from->css); > + rcu_read_unlock(); > + if (id == lookup_swap_cgroup(ent)) { > ret = MC_TARGET_SWAP; > if (target) > target->ent = ent; > > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [BUGFIX][PATCH] memcg rcu lock fix v3 2010-04-23 4:03 ` [BUGFIX][PATCH] memcg rcu lock fix v3 KAMEZAWA Hiroyuki 2010-04-23 4:41 ` Daisuke Nishimura @ 2010-04-23 6:10 ` Li Zefan 2010-04-23 6:05 ` KAMEZAWA Hiroyuki 2010-04-23 7:00 ` Balbir Singh 2010-04-23 19:34 ` Paul E. McKenney 3 siblings, 1 reply; 17+ messages in thread From: Li Zefan @ 2010-04-23 6:10 UTC (permalink / raw) To: KAMEZAWA Hiroyuki Cc: Balbir Singh, Daisuke Nishimura, Paul E. McKenney, linux-mm@kvack.org, LKML, akpm@linux-foundation.org > 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> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [BUGFIX][PATCH] memcg rcu lock fix v3 2010-04-23 6:10 ` Li Zefan @ 2010-04-23 6:05 ` KAMEZAWA Hiroyuki 0 siblings, 0 replies; 17+ messages in thread From: KAMEZAWA Hiroyuki @ 2010-04-23 6:05 UTC (permalink / raw) To: Li Zefan Cc: Balbir Singh, Daisuke Nishimura, Paul E. McKenney, linux-mm@kvack.org, LKML, akpm@linux-foundation.org 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [BUGFIX][PATCH] memcg rcu lock fix v3 2010-04-23 4:03 ` [BUGFIX][PATCH] memcg rcu lock fix v3 KAMEZAWA Hiroyuki 2010-04-23 4:41 ` Daisuke Nishimura 2010-04-23 6:10 ` Li Zefan @ 2010-04-23 7:00 ` Balbir Singh 2010-04-23 6:57 ` KAMEZAWA Hiroyuki 2010-04-23 19:34 ` Paul E. McKenney 3 siblings, 1 reply; 17+ messages in thread From: Balbir Singh @ 2010-04-23 7:00 UTC (permalink / raw) To: KAMEZAWA Hiroyuki Cc: Li Zefan, Daisuke Nishimura, Paul E. McKenney, linux-mm@kvack.org, LKML, akpm@linux-foundation.org * KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> [2010-04-23 13:03:49]: > On Fri, 23 Apr 2010 12:58:14 +0900 > KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote: > > > On Fri, 23 Apr 2010 11:55:16 +0800 > > Li Zefan <lizf@cn.fujitsu.com> wrote: > > > > > Li Zefan wrote: > > > > KAMEZAWA Hiroyuki wrote: > > > >> On Fri, 23 Apr 2010 11:00:41 +0800 > > > >> Li Zefan <lizf@cn.fujitsu.com> wrote: > > > >> > > > >>> with CONFIG_PROVE_RCU=y, I saw this warning, it's because > > > >>> css_id() is not under rcu_read_lock(). > > > >>> > > > >> Ok. Thank you for reporting. > > > >> This is ok ? > > > > > > > > Yes, and I did some more simple tests on memcg, no more warning > > > > showed up. > > > > > > > > > > oops, after trigging oom, I saw 2 more warnings: > > > > > > > Thank you for good testing. > v3 here...sorry too rapid posting... > Looking at the patch we seem to be protecting the use of only css_*(). I wonder if we should push down the rcu_read_*lock() semnatics to the css routines or is it just too instrusive to do it that way? -- Three Cheers, Balbir -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [BUGFIX][PATCH] memcg rcu lock fix v3 2010-04-23 7:00 ` Balbir Singh @ 2010-04-23 6:57 ` KAMEZAWA Hiroyuki 0 siblings, 0 replies; 17+ messages in thread From: KAMEZAWA Hiroyuki @ 2010-04-23 6:57 UTC (permalink / raw) To: balbir Cc: Li Zefan, Daisuke Nishimura, Paul E. McKenney, linux-mm@kvack.org, LKML, akpm@linux-foundation.org On Fri, 23 Apr 2010 12:30:11 +0530 Balbir Singh <balbir@linux.vnet.ibm.com> wrote: > * KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> [2010-04-23 13:03:49]: > > > On Fri, 23 Apr 2010 12:58:14 +0900 > > KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote: > > > > > On Fri, 23 Apr 2010 11:55:16 +0800 > > > Li Zefan <lizf@cn.fujitsu.com> wrote: > > > > > > > Li Zefan wrote: > > > > > KAMEZAWA Hiroyuki wrote: > > > > >> On Fri, 23 Apr 2010 11:00:41 +0800 > > > > >> Li Zefan <lizf@cn.fujitsu.com> wrote: > > > > >> > > > > >>> with CONFIG_PROVE_RCU=y, I saw this warning, it's because > > > > >>> css_id() is not under rcu_read_lock(). > > > > >>> > > > > >> Ok. Thank you for reporting. > > > > >> This is ok ? > > > > > > > > > > Yes, and I did some more simple tests on memcg, no more warning > > > > > showed up. > > > > > > > > > > > > > oops, after trigging oom, I saw 2 more warnings: > > > > > > > > > > Thank you for good testing. > > v3 here...sorry too rapid posting... > > > > Looking at the patch we seem to be protecting the use of only css_*(). > I wonder if we should push down the rcu_read_*lock() semnatics to the > css routines or is it just too instrusive to do it that way? > Maybe worth to consider for future patches for clean up. Thanks, -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [BUGFIX][PATCH] memcg rcu lock fix v3 2010-04-23 4:03 ` [BUGFIX][PATCH] memcg rcu lock fix v3 KAMEZAWA Hiroyuki ` (2 preceding siblings ...) 2010-04-23 7:00 ` Balbir Singh @ 2010-04-23 19:34 ` Paul E. McKenney 2010-04-24 2:08 ` KAMEZAWA Hiroyuki 3 siblings, 1 reply; 17+ messages in thread From: Paul E. McKenney @ 2010-04-23 19:34 UTC (permalink / raw) To: KAMEZAWA Hiroyuki Cc: Li Zefan, Balbir Singh, Daisuke Nishimura, linux-mm@kvack.org, LKML, akpm@linux-foundation.org On Fri, Apr 23, 2010 at 01:03:49PM +0900, KAMEZAWA Hiroyuki wrote: > On Fri, 23 Apr 2010 12:58:14 +0900 > KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote: > > > On Fri, 23 Apr 2010 11:55:16 +0800 > > Li Zefan <lizf@cn.fujitsu.com> wrote: > > > > > Li Zefan wrote: > > > > KAMEZAWA Hiroyuki wrote: > > > >> On Fri, 23 Apr 2010 11:00:41 +0800 > > > >> Li Zefan <lizf@cn.fujitsu.com> wrote: > > > >> > > > >>> with CONFIG_PROVE_RCU=y, I saw this warning, it's because > > > >>> css_id() is not under rcu_read_lock(). > > > >>> > > > >> Ok. Thank you for reporting. > > > >> This is ok ? > > > > > > > > Yes, and I did some more simple tests on memcg, no more warning > > > > showed up. > > > > > > > > > > oops, after trigging oom, I saw 2 more warnings: > > > > > > > Thank you for good testing. > v3 here...sorry too rapid posting... > > == > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> I have queued this, thank you all! However, memcg_oom_wake_function() does not yet exist in the tree I am using, and is_target_pte_for_mc() has changed. I omitted the hunk for memcg_oom_wake_function() and edited the hunk for is_target_pte_for_mc(). I have queued this for others' testing, but if you would rather carry this patch up the memcg path, please let me know and I will drop it. Thanx, Paul > 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: > Pid: 31, comm: kswapd0 Not tainted 2.6.34-rc5-tip+ #13 > Call Trace: > [<c083c5d6>] ? printk+0x1d/0x1f > [<c0480744>] lockdep_rcu_dereference+0x94/0xb0 > [<c049d6ed>] css_id+0x5d/0x60 > [<c05165a5>] mem_cgroup_uncharge_swapcache+0x45/0xa0 > [<c0505e4f>] swapcache_free+0x3f/0x60 > [<c04e79e2>] __remove_mapping+0xb2/0xf0 > [<c04e7cbb>] shrink_page_list+0x26b/0x490 > [<c047f85d>] ? put_lock_stats+0xd/0x30 > [<c083fd67>] ? _raw_spin_unlock_irq+0x27/0x50 > [<c0482566>] ? trace_hardirqs_on_caller+0xb6/0x220 > [<c04e8158>] shrink_inactive_list+0x278/0x620 > [<c04729e1>] ? sched_clock_cpu+0x121/0x180 > [<c047e9b8>] ? trace_hardirqs_off_caller+0x18/0x130 > [<c047eadb>] ? trace_hardirqs_off+0xb/0x10 > [<c0843438>] ? sub_preempt_count+0x8/0x90 > [<c047f85d>] ? put_lock_stats+0xd/0x30 > [<c04e8704>] shrink_zone+0x204/0x3c0 > [<c083fcac>] ? _raw_spin_unlock+0x2c/0x50 > [<c04e951e>] kswapd+0x61e/0x7c0 > [<c04e6ed0>] ? isolate_pages_global+0x0/0x1f0 > [<c046bae0>] ? autoremove_wake_function+0x0/0x50 > [<c04e8f00>] ? kswapd+0x0/0x7c0 > [<c046b5e4>] kthread+0x74/0x80 > [<c046b570>] ? kthread+0x0/0x80 > [<c04035ba>] kernel_thread_helper+0x6/0x10 > > 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> > --- > mm/memcontrol.c | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > Index: linux-2.6.34-rc5-mm1/mm/memcontrol.c > =================================================================== > --- linux-2.6.34-rc5-mm1.orig/mm/memcontrol.c > +++ linux-2.6.34-rc5-mm1/mm/memcontrol.c > @@ -838,10 +838,12 @@ int task_in_mem_cgroup(struct task_struc > * enabled in "curr" and "curr" is a child of "mem" in *cgroup* > * hierarchy(even if use_hierarchy is disabled in "mem"). > */ > + rcu_read_lock(); > if (mem->use_hierarchy) > ret = css_is_ancestor(&curr->css, &mem->css); > else > ret = (curr == mem); > + rcu_read_unlock(); > css_put(&curr->css); > return ret; > } > @@ -1360,9 +1362,13 @@ static int memcg_oom_wake_function(wait_ > * Both of oom_wait_info->mem and wake_mem are stable under us. > * Then we can use css_is_ancestor without taking care of RCU. > */ > + rcu_read_lock(); > if (!css_is_ancestor(&oom_wait_info->mem->css, &wake_mem->css) && > - !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css)) > + !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css)) { > + rcu_read_unlock(); > return 0; > + } > + rcu_read_unlock(); > > wakeup: > return autoremove_wake_function(wait, mode, sync, arg); > @@ -2401,7 +2407,9 @@ mem_cgroup_uncharge_swapcache(struct pag > > /* record memcg information */ > if (do_swap_account && swapout && memcg) { > + rcu_read_lock(); > swap_cgroup_record(ent, css_id(&memcg->css)); > + rcu_read_unlock(); > mem_cgroup_get(memcg); > } > if (swapout && memcg) > @@ -2458,8 +2466,10 @@ static int mem_cgroup_move_swap_account( > { > unsigned short old_id, new_id; > > + rcu_read_lock(); > old_id = css_id(&from->css); > new_id = css_id(&to->css); > + rcu_read_unlock(); > > if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { > mem_cgroup_swap_statistics(from, false); > @@ -4303,7 +4313,11 @@ static int is_target_pte_for_mc(struct v > } > /* Threre is a swap entry and a page doesn't exist or isn't charged */ > if (ent.val && !ret) { > - if (css_id(&mc.from->css) == lookup_swap_cgroup(ent)) { > + unsigned short id; > + rcu_read_lock(); > + id = css_id(&mc.from->css); > + rcu_read_unlock(); > + if (id == lookup_swap_cgroup(ent)) { > ret = MC_TARGET_SWAP; > if (target) > target->ent = ent; > > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [BUGFIX][PATCH] memcg rcu lock fix v3 2010-04-23 19:34 ` Paul E. McKenney @ 2010-04-24 2:08 ` KAMEZAWA Hiroyuki 2010-04-24 4:27 ` Paul E. McKenney 0 siblings, 1 reply; 17+ messages in thread From: KAMEZAWA Hiroyuki @ 2010-04-24 2:08 UTC (permalink / raw) To: paulmck Cc: Li Zefan, Balbir Singh, Daisuke Nishimura, linux-mm@kvack.org, LKML, akpm@linux-foundation.org On Fri, 23 Apr 2010 12:34:06 -0700 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote: > On Fri, Apr 23, 2010 at 01:03:49PM +0900, KAMEZAWA Hiroyuki wrote: > > On Fri, 23 Apr 2010 12:58:14 +0900 > > KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote: > > > > > On Fri, 23 Apr 2010 11:55:16 +0800 > > > Li Zefan <lizf@cn.fujitsu.com> wrote: > > > > > > > Li Zefan wrote: > > > > > KAMEZAWA Hiroyuki wrote: > > > > >> On Fri, 23 Apr 2010 11:00:41 +0800 > > > > >> Li Zefan <lizf@cn.fujitsu.com> wrote: > > > > >> > > > > >>> with CONFIG_PROVE_RCU=y, I saw this warning, it's because > > > > >>> css_id() is not under rcu_read_lock(). > > > > >>> > > > > >> Ok. Thank you for reporting. > > > > >> This is ok ? > > > > > > > > > > Yes, and I did some more simple tests on memcg, no more warning > > > > > showed up. > > > > > > > > > > > > > oops, after trigging oom, I saw 2 more warnings: > > > > > > > > > > Thank you for good testing. > > v3 here...sorry too rapid posting... > > > > == > > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> > > I have queued this, thank you all! > > However, memcg_oom_wake_function() does not yet exist in the tree > I am using, and is_target_pte_for_mc() has changed. I omitted the > hunk for memcg_oom_wake_function() and edited the hunk for > is_target_pte_for_mc(). > Ok, memcg_oom_wake_function is for -mm. I'll prepare another patch for -mm. > I have queued this for others' testing, but if you would rather carry > this patch up the memcg path, please let me know and I will drop it. > I think it's ok to be fixed by your tree. I'll look at memcg later and fix remaining things. Thanks, -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [BUGFIX][PATCH] memcg rcu lock fix v3 2010-04-24 2:08 ` KAMEZAWA Hiroyuki @ 2010-04-24 4:27 ` Paul E. McKenney 0 siblings, 0 replies; 17+ messages in thread From: Paul E. McKenney @ 2010-04-24 4:27 UTC (permalink / raw) To: KAMEZAWA Hiroyuki Cc: Li Zefan, Balbir Singh, Daisuke Nishimura, linux-mm@kvack.org, LKML, akpm@linux-foundation.org On Sat, Apr 24, 2010 at 11:08:05AM +0900, KAMEZAWA Hiroyuki wrote: > On Fri, 23 Apr 2010 12:34:06 -0700 > "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote: > > > On Fri, Apr 23, 2010 at 01:03:49PM +0900, KAMEZAWA Hiroyuki wrote: > > > On Fri, 23 Apr 2010 12:58:14 +0900 > > > KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote: > > > > > > > On Fri, 23 Apr 2010 11:55:16 +0800 > > > > Li Zefan <lizf@cn.fujitsu.com> wrote: > > > > > > > > > Li Zefan wrote: > > > > > > KAMEZAWA Hiroyuki wrote: > > > > > >> On Fri, 23 Apr 2010 11:00:41 +0800 > > > > > >> Li Zefan <lizf@cn.fujitsu.com> wrote: > > > > > >> > > > > > >>> with CONFIG_PROVE_RCU=y, I saw this warning, it's because > > > > > >>> css_id() is not under rcu_read_lock(). > > > > > >>> > > > > > >> Ok. Thank you for reporting. > > > > > >> This is ok ? > > > > > > > > > > > > Yes, and I did some more simple tests on memcg, no more warning > > > > > > showed up. > > > > > > > > > > > > > > > > oops, after trigging oom, I saw 2 more warnings: > > > > > > > > > > > > > Thank you for good testing. > > > v3 here...sorry too rapid posting... > > > > > > == > > > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> > > > > I have queued this, thank you all! > > > > However, memcg_oom_wake_function() does not yet exist in the tree > > I am using, and is_target_pte_for_mc() has changed. I omitted the > > hunk for memcg_oom_wake_function() and edited the hunk for > > is_target_pte_for_mc(). > > > Ok, memcg_oom_wake_function is for -mm. I'll prepare another patch for -mm. > > > > I have queued this for others' testing, but if you would rather carry > > this patch up the memcg path, please let me know and I will drop it. > > > I think it's ok to be fixed by your tree. I'll look at memcg later and > fix remaining things. Sounds good! Thanx, Paul -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 17+ messages in thread
end of thread, other threads:[~2010-04-24 4:27 UTC | newest] Thread overview: 17+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2010-04-23 3:00 [BUG] an RCU warning in memcg Li Zefan 2010-04-23 3:14 ` [BUGFIX][PATCH] memcg rcu lock fix in swap code (Was " KAMEZAWA Hiroyuki 2010-04-23 3:32 ` Balbir Singh 2010-04-23 3:49 ` Li Zefan 2010-04-23 3:55 ` Li Zefan 2010-04-23 3:50 ` KAMEZAWA Hiroyuki 2010-04-23 4:02 ` Li Zefan 2010-04-23 3:58 ` [BUGFIX][PATCH] memcg rcu lock fix v2 KAMEZAWA Hiroyuki 2010-04-23 4:03 ` [BUGFIX][PATCH] memcg rcu lock fix v3 KAMEZAWA Hiroyuki 2010-04-23 4:41 ` Daisuke Nishimura 2010-04-23 6:10 ` Li Zefan 2010-04-23 6:05 ` KAMEZAWA Hiroyuki 2010-04-23 7:00 ` Balbir Singh 2010-04-23 6:57 ` KAMEZAWA Hiroyuki 2010-04-23 19:34 ` Paul E. McKenney 2010-04-24 2:08 ` KAMEZAWA Hiroyuki 2010-04-24 4:27 ` Paul E. McKenney
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).