Kirill has reported the following:
[ 2.386563] Task in /test killed as a result of limit of /test
[ 2.387326] memory: usage 10240kB, limit 10240kB, failcnt 51
[ 2.388098] memory+swap: usage 10240kB, limit 10240kB, failcnt 0
[ 2.388861] kmem: usage 0kB, limit 18014398509481983kB, failcnt 0
[ 2.389640] Memory cgroup stats for /test:
[ 2.390178] BUG: sleeping function called from invalid context at /home/space/kas/git/public/linux/kernel/cpu.c:68
[ 2.391516] in_atomic(): 1, irqs_disabled(): 0, pid: 66, name: memcg_test
[ 2.392416] 2 locks held by memcg_test/66:
[ 2.392945] #0: (memcg_oom_lock#2){+.+...}, at: [<ffffffff81131014>] pagefault_out_of_memory+0x14/0x90
[ 2.394233] #1: (oom_info_lock){+.+...}, at: [<ffffffff81197b2a>] mem_cgroup_print_oom_info+0x2a/0x390
[ 2.395496] CPU: 2 PID: 66 Comm: memcg_test Not tainted 3.14.0-rc1-dirty #745
[ 2.396536] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS Bochs 01/01/2011
[ 2.397540] ffffffff81a3cc90 ffff88081d26dba0 ffffffff81776ea3 0000000000000000
[ 2.398541] ffff88081d26dbc8 ffffffff8108418a 0000000000000000 ffff88081d15c000
[ 2.399533] 0000000000000000 ffff88081d26dbd8 ffffffff8104f6bc ffff88081d26dc10
[ 2.400588] Call Trace:
[ 2.400908] [<ffffffff81776ea3>] dump_stack+0x4d/0x66
[ 2.401578] [<ffffffff8108418a>] __might_sleep+0x16a/0x210
[ 2.402295] [<ffffffff8104f6bc>] get_online_cpus+0x1c/0x60
[ 2.403005] [<ffffffff8118fb67>] mem_cgroup_read_stat+0x27/0xb0
[ 2.403769] [<ffffffff81197d60>] mem_cgroup_print_oom_info+0x260/0x390
[ 2.404653] [<ffffffff8177314e>] dump_header+0x88/0x251
[ 2.405342] [<ffffffff810a3bfd>] ? trace_hardirqs_on+0xd/0x10
[ 2.406098] [<ffffffff81130618>] oom_kill_process+0x258/0x3d0
[ 2.406833] [<ffffffff81198746>] mem_cgroup_oom_synchronize+0x656/0x6c0
[ 2.407674] [<ffffffff811973a0>] ? mem_cgroup_charge_common+0xd0/0xd0
[ 2.408553] [<ffffffff81131014>] pagefault_out_of_memory+0x14/0x90
[ 2.409354] [<ffffffff817712f7>] mm_fault_error+0x91/0x189
[ 2.410069] [<ffffffff81783eae>] __do_page_fault+0x48e/0x580
[ 2.410791] [<ffffffff8108f656>] ? local_clock+0x16/0x30
[ 2.411467] [<ffffffff810a3bfd>] ? trace_hardirqs_on+0xd/0x10
[ 2.412248] [<ffffffff8177f6fc>] ? _raw_spin_unlock_irq+0x2c/0x40
[ 2.413039] [<ffffffff8108312b>] ? finish_task_switch+0x7b/0x100
[ 2.413821] [<ffffffff813b954a>] ? trace_hardirqs_off_thunk+0x3a/0x3c
[ 2.414652] [<ffffffff81783fae>] do_page_fault+0xe/0x10
[ 2.415330] [<ffffffff81780552>] page_fault+0x22/0x30
which complains that mem_cgroup_read_stat cannot be called from an
atomic context but mem_cgroup_print_oom_info takes a spinlock.
Change oom_info_lock to a mutex.
This has been introduced by 947b3dd1a84b (memcg, oom: lock
mem_cgroup_print_oom_info).
Reported-by: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Michal Hocko <mhocko@xxxxxxx>
---
mm/memcontrol.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 19d5d4274e22..55e6731ebcd5 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1687,7 +1687,7 @@ void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
* protects memcg_name and makes sure that parallel ooms do not
* interleave
*/
- static DEFINE_SPINLOCK(oom_info_lock);
+ static DEFINE_MUTEX(oom_info_lock);
struct cgroup *task_cgrp;
struct cgroup *mem_cgrp;
static char memcg_name[PATH_MAX];
@@ -1698,7 +1698,7 @@ void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
if (!p)
return;
- spin_lock(&oom_info_lock);
+ mutex_lock(&oom_info_lock);
rcu_read_lock();
mem_cgrp = memcg->css.cgroup;
@@ -1767,7 +1767,7 @@ done:
pr_cont("\n");
}
- spin_unlock(&oom_info_lock);
+ mutex_unlock(&oom_info_lock);
}
/*
--
1.9.rc1
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