From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f178.google.com (mail-ig0-f178.google.com [209.85.213.178]) by kanga.kvack.org (Postfix) with ESMTP id CE0796B0038 for ; Thu, 2 Apr 2015 19:01:46 -0400 (EDT) Received: by igbqf9 with SMTP id qf9so85298925igb.1 for ; Thu, 02 Apr 2015 16:01:46 -0700 (PDT) Received: from mail-ie0-x22c.google.com (mail-ie0-x22c.google.com. [2607:f8b0:4001:c03::22c]) by mx.google.com with ESMTPS id b6si5973007icl.49.2015.04.02.16.01.46 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 02 Apr 2015 16:01:46 -0700 (PDT) Received: by iedfl3 with SMTP id fl3so90435530ied.1 for ; Thu, 02 Apr 2015 16:01:46 -0700 (PDT) Date: Thu, 2 Apr 2015 16:01:44 -0700 (PDT) From: David Rientjes Subject: [patch] android, lmk: avoid setting TIF_MEMDIE if process has already exited In-Reply-To: Message-ID: References: <1427264236-17249-1-git-send-email-hannes@cmpxchg.org> <1427264236-17249-4-git-send-email-hannes@cmpxchg.org> <20150326110532.GB18560@cmpxchg.org> MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="531381512-533442710-1428015705=:15536" Sender: owner-linux-mm@kvack.org List-ID: To: Greg Kroah-Hartman Cc: =?UTF-8?Q?Arve_Hj=C3=B8nnev=C3=A5g?= , Riley Andrews , Andrew Morton , Johannes Weiner , Michal Hocko , linux-kernel@vger.kernel.org, linux-mm@kvack.org, devel@driverdev.osuosl.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --531381512-533442710-1428015705=:15536 Content-Type: TEXT/PLAIN; charset=UTF-8 Content-Transfer-Encoding: 8BIT TIF_MEMDIE should not be set on a process if it does not have a valid ->mm, and this is protected by task_lock(). If TIF_MEMDIE gets set after the mm has detached, and the process fails to exit, then the oom killer will defer forever waiting for it to exit. Make sure that the mm is still valid before setting TIF_MEMDIE by way of mark_tsk_oom_victim(). Cc: "Arve HjA,nnevAJPYg" Cc: Riley Andrews Acked-by: Michal Hocko Signed-off-by: David Rientjes --- drivers/staging/android/lowmemorykiller.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/drivers/staging/android/lowmemorykiller.c b/drivers/staging/android/lowmemorykiller.c --- a/drivers/staging/android/lowmemorykiller.c +++ b/drivers/staging/android/lowmemorykiller.c @@ -156,20 +156,27 @@ static unsigned long lowmem_scan(struct shrinker *s, struct shrink_control *sc) p->pid, p->comm, oom_score_adj, tasksize); } if (selected) { - lowmem_print(1, "send sigkill to %d (%s), adj %hd, size %d\n", - selected->pid, selected->comm, - selected_oom_score_adj, selected_tasksize); - lowmem_deathpending_timeout = jiffies + HZ; + task_lock(selected); + if (!selected->mm) { + /* Already exited, cannot do mark_tsk_oom_victim() */ + task_unlock(selected); + goto out; + } /* * FIXME: lowmemorykiller shouldn't abuse global OOM killer * infrastructure. There is no real reason why the selected * task should have access to the memory reserves. */ mark_tsk_oom_victim(selected); + task_unlock(selected); + lowmem_print(1, "send sigkill to %d (%s), adj %hd, size %d\n", + selected->pid, selected->comm, + selected_oom_score_adj, selected_tasksize); + lowmem_deathpending_timeout = jiffies + HZ; send_sig(SIGKILL, selected, 0); rem += selected_tasksize; } - +out: lowmem_print(4, "lowmem_scan %lu, %x, return %lu\n", sc->nr_to_scan, sc->gfp_mask, rem); rcu_read_unlock(); --531381512-533442710-1428015705=:15536-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org