memcg: change oom_info_lock to mutex

Kirill has reported the following:

  Task in /test killed as a result of limit of /test
  memory: usage 10240kB, limit 10240kB, failcnt 51
  memory+swap: usage 10240kB, limit 10240kB, failcnt 0
  kmem: usage 0kB, limit 18014398509481983kB, failcnt 0
  Memory cgroup stats for /test:

  BUG: sleeping function called from invalid context at kernel/cpu.c:68
  in_atomic(): 1, irqs_disabled(): 0, pid: 66, name: memcg_test
  2 locks held by memcg_test/66:
   #0:  (memcg_oom_lock#2){+.+...}, at: [<ffffffff81131014>] pagefault_out_of_memory+0x14/0x90
   #1:  (oom_info_lock){+.+...}, at: [<ffffffff81197b2a>] mem_cgroup_print_oom_info+0x2a/0x390
  CPU: 2 PID: 66 Comm: memcg_test Not tainted 3.14.0-rc1-dirty #745
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS Bochs 01/01/2011
  Call Trace:
    __might_sleep+0x16a/0x210
    get_online_cpus+0x1c/0x60
    mem_cgroup_read_stat+0x27/0xb0
    mem_cgroup_print_oom_info+0x260/0x390
    dump_header+0x88/0x251
    ? trace_hardirqs_on+0xd/0x10
    oom_kill_process+0x258/0x3d0
    mem_cgroup_oom_synchronize+0x656/0x6c0
    ? mem_cgroup_charge_common+0xd0/0xd0
    pagefault_out_of_memory+0x14/0x90
    mm_fault_error+0x91/0x189
    __do_page_fault+0x48e/0x580
    do_page_fault+0xe/0x10
    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 was introduced by 947b3dd1a8 ("memcg, oom: lock
mem_cgroup_print_oom_info").

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Reported-by: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Michal Hocko 2014-02-25 15:01:44 -08:00 committed by Linus Torvalds
parent 9845cbbd11
commit 08088cb9ac

View File

@ -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 @@ void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
pr_cont("\n");
}
spin_unlock(&oom_info_lock);
mutex_unlock(&oom_info_lock);
}
/*