diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2014-08-08 14:19:17 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-10-05 14:54:16 -0700 |
| commit | 3581832971e7f7bac0d9d1c11c7d985b1edef7c9 (patch) | |
| tree | 2091af7c0c745f7e31b02e01f94372d0a92101f4 | |
| parent | d081edee3aa2695765ff836197846b89ab712b05 (diff) | |
vm_is_stack: use for_each_thread() rather then buggy while_each_thread()
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@redhat.com>
Reported-by: Aleksei Besogonov <alex.besogonov@gmail.com>
Tested-by: Aleksei Besogonov <alex.besogonov@gmail.com>
Suggested-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Li Zefan <lizefan@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | mm/util.c | 9 |
1 files changed, 3 insertions, 6 deletions
diff --git a/mm/util.c b/mm/util.c index ab1424dbe2e6..0b1725254ff1 100644 --- a/mm/util.c +++ b/mm/util.c @@ -272,17 +272,14 @@ pid_t vm_is_stack(struct task_struct *task, 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(); } |