This is a note to let you know that I've just added the patch titled
vm_is_stack: use for_each_thread() rather then buggy while_each_thread()
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:
vm_is_stack-use-for_each_thread-rather-then-buggy-while_each_thread.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 4449a51a7c281602d3a385044ab928322a122a02 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Date: Fri, 8 Aug 2014 14:19:17 -0700
Subject: vm_is_stack: use for_each_thread() rather then buggy while_each_thread()
From: Oleg Nesterov <oleg@xxxxxxxxxx>
commit 4449a51a7c281602d3a385044ab928322a122a02 upstream.
Aleksei hit the soft lockup during reading /proc/PID/smaps. David
investigated the problem and suggested the right fix.
while_each_thread() is racy and should die, this patch updates
vm_is_stack().
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Reported-by: Aleksei Besogonov <alex.besogonov@xxxxxxxxx>
Tested-by: Aleksei Besogonov <alex.besogonov@xxxxxxxxx>
Suggested-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/util.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
--- a/mm/util.c
+++ b/mm/util.c
@@ -272,17 +272,14 @@ pid_t vm_is_stack(struct task_struct *ta
if (in_group) {
struct task_struct *t;
- rcu_read_lock();
- if (!pid_alive(task))
- goto done;
- t = task;
- do {
+ rcu_read_lock();
+ for_each_thread(task, t) {
if (vm_is_stack_for_task(t, vma)) {
ret = t->pid;
goto done;
}
- } while_each_thread(task, t);
+ }
done:
rcu_read_unlock();
}
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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