Commit ad962441 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

oom_kill: has_intersects_mems_allowed() needs rcu_read_lock()

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
Signed-off-by: default avatarOleg Nesterov <>
Reviewed-by: default avatarSergey Dyasly <>
Tested-by: default avatarSergey Dyasly <>
Reviewed-by: default avatarSameer Nanda <>
Cc: "Eric W. Biederman" <>
Cc: Frederic Weisbecker <>
Cc: Mandeep Singh Baines <>
Cc: "Ma, Xindong" <>
Reviewed-by: default avatarMichal Hocko <>
Cc: "Tu, Xiaobing" <>
Acked-by: default avatarDavid Rientjes <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 1da4db0c
......@@ -47,18 +47,20 @@ static DEFINE_SPINLOCK(zone_scan_lock);
* 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;
for_each_thread(start, tsk) {
if (mask) {
......@@ -67,19 +69,20 @@ static bool has_intersects_mems_allowed(struct task_struct *tsk,
* 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)
return false;
return ret;
static bool has_intersects_mems_allowed(struct task_struct *tsk,
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