This is a note to let you know that I've just added the patch titled
oom_kill: has_intersects_mems_allowed() needs rcu_read_lock()
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
oom_kill-has_intersects_mems_allowed-needs-rcu_read_lock.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ad96244179fbd55b40c00f10f399bc04739b8e1f Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Date: Tue, 21 Jan 2014 15:50:00 -0800
Subject: oom_kill: has_intersects_mems_allowed() needs rcu_read_lock()
From: Oleg Nesterov <oleg@xxxxxxxxxx>
commit ad96244179fbd55b40c00f10f399bc04739b8e1f upstream.
At least out_of_memory() calls has_intersects_mems_allowed() without
even rcu_read_lock(), this is obviously buggy.
Add the necessary rcu_read_lock(). This means that we can not simply
return from the loop, we need "bool ret" and "break".
While at it, swap the names of task_struct's (the argument and the
local). This cleans up the code a little bit and avoids the unnecessary
initialization.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Reviewed-by: Sergey Dyasly <dserrg@xxxxxxxxx>
Tested-by: Sergey Dyasly <dserrg@xxxxxxxxx>
Reviewed-by: Sameer Nanda <snanda@xxxxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Mandeep Singh Baines <msb@xxxxxxxxxxxx>
Cc: "Ma, Xindong" <xindong.ma@xxxxxxxxx>
Reviewed-by: Michal Hocko <mhocko@xxxxxxx>
Cc: "Tu, Xiaobing" <xiaobing.tu@xxxxxxxxx>
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Li Zefan <lizefan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/oom_kill.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -47,18 +47,20 @@ static DEFINE_SPINLOCK(zone_scan_lock);
#ifdef CONFIG_NUMA
/**
* has_intersects_mems_allowed() - check task eligiblity for kill
- * @tsk: task struct of which task to consider
+ * @start: task struct of which task to consider
* @mask: nodemask passed to page allocator for mempolicy ooms
*
* Task eligibility is determined by whether or not a candidate task, @tsk,
* shares the same mempolicy nodes as current if it is bound by such a policy
* and whether or not it has the same set of allowed cpuset nodes.
*/
-static bool has_intersects_mems_allowed(struct task_struct *tsk,
+static bool has_intersects_mems_allowed(struct task_struct *start,
const nodemask_t *mask)
{
- struct task_struct *start = tsk;
+ struct task_struct *tsk;
+ bool ret = false;
+ rcu_read_lock();
for_each_thread(start, tsk) {
if (mask) {
/*
@@ -67,19 +69,20 @@ static bool has_intersects_mems_allowed(
* mempolicy intersects current, otherwise it may be
* needlessly killed.
*/
- if (mempolicy_nodemask_intersects(tsk, mask))
- return true;
+ ret = mempolicy_nodemask_intersects(tsk, mask);
} else {
/*
* This is not a mempolicy constrained oom, so only
* check the mems of tsk's cpuset.
*/
- if (cpuset_mems_allowed_intersects(current, tsk))
- return true;
+ ret = cpuset_mems_allowed_intersects(current, tsk);
}
+ if (ret)
+ break;
}
+ rcu_read_unlock();
- return false;
+ return ret;
}
#else
static bool has_intersects_mems_allowed(struct task_struct *tsk,
Patches currently in stable-queue which might be from oleg@xxxxxxxxxx are
queue-3.10/introduce-for_each_thread-to-replace-the-buggy-while_each_thread.patch
queue-3.10/oom_kill-change-oom_kill.c-to-use-for_each_thread.patch
queue-3.10/kernel-fork.c-copy_process-unify-clone_thread-or-thread_group_leader-code.patch
queue-3.10/oom_kill-add-rcu_read_lock-into-find_lock_task_mm.patch
queue-3.10/vm_is_stack-use-for_each_thread-rather-then-buggy-while_each_thread.patch
queue-3.10/oom_kill-has_intersects_mems_allowed-needs-rcu_read_lock.patch
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