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author | Oleg Nesterov <oleg@redhat.com> | 2014-01-21 15:49:58 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-01-21 16:19:46 -0800 |
commit | 1da4db0cd5c8a31d4468ec906b413e75e604b465 (patch) | |
tree | 7b413ea40f6630376032d59bd7525e0372ea2d6e | |
parent | 0c740d0afc3bff0a097ad03a1c8df92757516f5c (diff) | |
download | op-kernel-dev-1da4db0cd5c8a31d4468ec906b413e75e604b465.zip op-kernel-dev-1da4db0cd5c8a31d4468ec906b413e75e604b465.tar.gz |
oom_kill: change oom_kill.c to use for_each_thread()
Change oom_kill.c to use for_each_thread() rather than the racy
while_each_thread() which can loop forever if we race with exit.
Note also that most users were buggy even if while_each_thread() was
fine, the task can exit even _before_ rcu_read_lock().
Fortunately the new for_each_thread() only requires the stable
task_struct, so this change fixes both problems.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Sergey Dyasly <dserrg@gmail.com>
Tested-by: Sergey Dyasly <dserrg@gmail.com>
Reviewed-by: Sameer Nanda <snanda@chromium.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mandeep Singh Baines <msb@chromium.org>
Cc: "Ma, Xindong" <xindong.ma@intel.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: "Tu, Xiaobing" <xiaobing.tu@intel.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>
-rw-r--r-- | mm/oom_kill.c | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 1e4a600..96d7945 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -59,7 +59,7 @@ static bool has_intersects_mems_allowed(struct task_struct *tsk, { struct task_struct *start = tsk; - do { + for_each_thread(start, tsk) { if (mask) { /* * If this is a mempolicy constrained oom, tsk's @@ -77,7 +77,7 @@ static bool has_intersects_mems_allowed(struct task_struct *tsk, if (cpuset_mems_allowed_intersects(current, tsk)) return true; } - } while_each_thread(start, tsk); + } return false; } @@ -97,14 +97,14 @@ static bool has_intersects_mems_allowed(struct task_struct *tsk, */ struct task_struct *find_lock_task_mm(struct task_struct *p) { - struct task_struct *t = p; + struct task_struct *t; - do { + for_each_thread(p, t) { task_lock(t); if (likely(t->mm)) return t; task_unlock(t); - } while_each_thread(p, t); + } return NULL; } @@ -301,7 +301,7 @@ static struct task_struct *select_bad_process(unsigned int *ppoints, unsigned long chosen_points = 0; rcu_read_lock(); - do_each_thread(g, p) { + for_each_process_thread(g, p) { unsigned int points; switch (oom_scan_process_thread(p, totalpages, nodemask, @@ -323,7 +323,7 @@ static struct task_struct *select_bad_process(unsigned int *ppoints, chosen = p; chosen_points = points; } - } while_each_thread(g, p); + } if (chosen) get_task_struct(chosen); rcu_read_unlock(); @@ -406,7 +406,7 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, { struct task_struct *victim = p; struct task_struct *child; - struct task_struct *t = p; + struct task_struct *t; struct mm_struct *mm; unsigned int victim_points = 0; static DEFINE_RATELIMIT_STATE(oom_rs, DEFAULT_RATELIMIT_INTERVAL, @@ -437,7 +437,7 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, * still freeing memory. */ read_lock(&tasklist_lock); - do { + for_each_thread(p, t) { list_for_each_entry(child, &t->children, sibling) { unsigned int child_points; @@ -455,7 +455,7 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, get_task_struct(victim); } } - } while_each_thread(p, t); + } read_unlock(&tasklist_lock); rcu_read_lock(); |