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author | KOSAKI Motohiro | 2010-08-19 23:13:39 +0200 |
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committer | Linus Torvalds | 2010-08-20 18:34:55 +0200 |
commit | 8d6c83f0ba5e1bd1e8bb2e3c7de4c276dc247f99 (patch) | |
tree | 58b777adffdaf754b97e6359a325bccdd8919346 /arch/um/os-Linux | |
parent | oom: fix tasklist_lock leak (diff) | |
download | kernel-qcow2-linux-8d6c83f0ba5e1bd1e8bb2e3c7de4c276dc247f99.tar.gz kernel-qcow2-linux-8d6c83f0ba5e1bd1e8bb2e3c7de4c276dc247f99.tar.xz kernel-qcow2-linux-8d6c83f0ba5e1bd1e8bb2e3c7de4c276dc247f99.zip |
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 'arch/um/os-Linux')
0 files changed, 0 insertions, 0 deletions