Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758368AbaJCWbc (ORCPT ); Fri, 3 Oct 2014 18:31:32 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:47632 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756338AbaJCW3t (ORCPT ); Fri, 3 Oct 2014 18:29:49 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Oleg Nesterov , Sergey Dyasly , Sameer Nanda , "Eric W. Biederman" , Frederic Weisbecker , Mandeep Singh Baines , "Ma, Xindong" , Michal Hocko , "Tu, Xiaobing" , David Rientjes , Andrew Morton , Linus Torvalds , Li Zefan Subject: [PATCH 3.10 140/143] oom_kill: change oom_kill.c to use for_each_thread() Date: Fri, 3 Oct 2014 14:35:35 -0700 Message-Id: <20141003213318.671273467@linuxfoundation.org> X-Mailer: git-send-email 2.1.2 In-Reply-To: <20141003213314.470709810@linuxfoundation.org> References: <20141003213314.470709810@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Oleg Nesterov 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 Reviewed-by: Sergey Dyasly Tested-by: Sergey Dyasly Reviewed-by: Sameer Nanda Cc: "Eric W. Biederman" Cc: Frederic Weisbecker Cc: Mandeep Singh Baines Cc: "Ma, Xindong" Reviewed-by: Michal Hocko Cc: "Tu, Xiaobing" Acked-by: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Cc: Li Zefan Signed-off-by: Greg Kroah-Hartman --- mm/oom_kill.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -59,7 +59,7 @@ static bool has_intersects_mems_allowed( { 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( 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 *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_pr 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_pr 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 { 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 * 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 get_task_struct(victim); } } - } while_each_thread(p, t); + } read_unlock(&tasklist_lock); rcu_read_lock(); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/