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| author | KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> | 2010-08-19 21:13:39 (GMT) |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-08-20 16:34:55 (GMT) |
| commit | 8d6c83f0ba5e1bd1e8bb2e3c7de4c276dc247f99 (patch) | |
| tree | 58b777adffdaf754b97e6359a325bccdd8919346 /mm | |
| parent | b52723c5607f7684c2c0c075f86f86da0d7fb6d0 (diff) | |
| download | linux-fsl-qoriq-8d6c83f0ba5e1bd1e8bb2e3c7de4c276dc247f99.tar.xz | |
oom: __task_cred() need rcu_read_lock()
dump_tasks() needs to hold the RCU read lock around its access of the
target task's UID. To this end it should use task_uid() as it only needs
that one thing from the creds.
The fact that dump_tasks() holds tasklist_lock is insufficient to prevent the
target process replacing its credentials on another CPU.
Then, this patch change to call rcu_read_lock() explicitly.
===================================================
[ INFO: suspicious rcu_dereference_check() usage. ]
---------------------------------------------------
mm/oom_kill.c:410 invoked rcu_dereference_check() without protection!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 1
4 locks held by kworker/1:2/651:
#0: (events){+.+.+.}, at: [<ffffffff8106aae7>]
process_one_work+0x137/0x4a0
#1: (moom_work){+.+...}, at: [<ffffffff8106aae7>]
process_one_work+0x137/0x4a0
#2: (tasklist_lock){.+.+..}, at: [<ffffffff810fafd4>]
out_of_memory+0x164/0x3f0
#3: (&(&p->alloc_lock)->rlock){+.+...}, at: [<ffffffff810fa48e>]
find_lock_task_mm+0x2e/0x70
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/oom_kill.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c index c48c5ef..fc81cb2 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -372,7 +372,7 @@ static void dump_tasks(const struct mem_cgroup *mem) } pr_info("[%5d] %5d %5d %8lu %8lu %3u %3d %5d %s\n", - task->pid, __task_cred(task)->uid, task->tgid, + task->pid, task_uid(task), task->tgid, task->mm->total_vm, get_mm_rss(task->mm), task_cpu(task), task->signal->oom_adj, task->signal->oom_score_adj, task->comm); |