linux-kernel - [PATCH 3.12 002/146] oom_kill: change oom_kill.c to use for_each

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <7fdd16a11979a1cdb9157d144574010700497b69.1402303820.git.jslaby@suse.cz>
Date:	Mon,  9 Jun 2014 10:48:57 +0200
From:	Jiri Slaby <jslaby@...e.cz>
To:	stable@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, Oleg Nesterov <oleg@...hat.com>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Mandeep Singh Baines <msb@...omium.org>,
	"Ma, Xindong" <xindong.ma@...el.com>,
	"Tu, Xiaobing" <xiaobing.tu@...el.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Jiri Slaby <jslaby@...e.cz>
Subject: [PATCH 3.12 002/146] oom_kill: change oom_kill.c to use for_each_thread()

From: Oleg Nesterov <oleg@...hat.com>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit 1da4db0cd5c8a31d4468ec906b413e75e604b465 upstream.

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@...hat.com>
Reviewed-by: Sergey Dyasly <dserrg@...il.com>
Tested-by: Sergey Dyasly <dserrg@...il.com>
Reviewed-by: Sameer Nanda <snanda@...omium.org>
Cc: "Eric W. Biederman" <ebiederm@...ssion.com>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Cc: Mandeep Singh Baines <msb@...omium.org>
Cc: "Ma, Xindong" <xindong.ma@...el.com>
Reviewed-by: Michal Hocko <mhocko@...e.cz>
Cc: "Tu, Xiaobing" <xiaobing.tu@...el.com>
Acked-by: David Rientjes <rientjes@...gle.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
---
 mm/oom_kill.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index e73f01c56d10..cae791c15c51 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();
-- 
1.9.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/