From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BF7E3C433E0 for ; Wed, 15 Jul 2020 23:37:34 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 895EA20656 for ; Wed, 15 Jul 2020 23:37:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 895EA20656 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=I-love.SAKURA.ne.jp Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E59296B0007; Wed, 15 Jul 2020 19:37:33 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E0A0B6B000A; Wed, 15 Jul 2020 19:37:33 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D46A36B000C; Wed, 15 Jul 2020 19:37:33 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0165.hostedemail.com [216.40.44.165]) by kanga.kvack.org (Postfix) with ESMTP id BFD6B6B0007 for ; Wed, 15 Jul 2020 19:37:33 -0400 (EDT) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 44F57181AC9BF for ; Wed, 15 Jul 2020 23:37:33 +0000 (UTC) X-FDA: 77041924386.26.duck22_3c0b76826efd Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin26.hostedemail.com (Postfix) with ESMTP id 1F7571804B65A for ; Wed, 15 Jul 2020 23:37:33 +0000 (UTC) X-HE-Tag: duck22_3c0b76826efd X-Filterd-Recvd-Size: 3337 Received: from www262.sakura.ne.jp (www262.sakura.ne.jp [202.181.97.72]) by imf19.hostedemail.com (Postfix) with ESMTP for ; Wed, 15 Jul 2020 23:37:31 +0000 (UTC) Received: from fsav108.sakura.ne.jp (fsav108.sakura.ne.jp [27.133.134.235]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 06FNas9G083247; Thu, 16 Jul 2020 08:36:54 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav108.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav108.sakura.ne.jp); Thu, 16 Jul 2020 08:36:54 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav108.sakura.ne.jp) Received: from [192.168.1.9] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 06FNarZT083239 (version=TLSv1.2 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 16 Jul 2020 08:36:54 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Subject: [PATCH] binder: Don't use mmput() from shrinker function. To: Greg Kroah-Hartman , Arve Hjonnevag , Todd Kjos , Martijn Coenen , Joel Fernandes , Christian Brauner , Michal Hocko References: <0000000000001fbbb605aa805c9b@google.com> Cc: syzbot , acme@kernel.org, alexander.shishkin@linux.intel.com, jolsa@redhat.com, linux-kernel@vger.kernel.org, mark.rutland@arm.com, mingo@redhat.com, namhyung@kernel.org, peterz@infradead.org, syzkaller-bugs@googlegroups.com, "open list:ANDROID DRIVERS" , linux-mm From: Tetsuo Handa Message-ID: <5ce3ee90-333e-638d-ac8c-cd6d7ab7aa3b@I-love.SAKURA.ne.jp> Date: Thu, 16 Jul 2020 08:36:52 +0900 User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <0000000000001fbbb605aa805c9b@google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 1F7571804B65A X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: syzbot is reporting that mmput() from shrinker function has a risk of deadlock [1]. Don't start synchronous teardown of mm when called from shrinker function. [1] https://syzkaller.appspot.com/bug?id=bc9e7303f537c41b2b0cc2dfcea3fc42964c2d45 Reported-by: syzbot Reported-by: syzbot Signed-off-by: Tetsuo Handa --- drivers/android/binder_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c index 42c672f1584e..cbe6aa77d50d 100644 --- a/drivers/android/binder_alloc.c +++ b/drivers/android/binder_alloc.c @@ -947,7 +947,7 @@ enum lru_status binder_alloc_free_page(struct list_head *item, trace_binder_unmap_user_end(alloc, index); } mmap_read_unlock(mm); - mmput(mm); + mmput_async(mm); trace_binder_unmap_kernel_start(alloc, index); -- 2.18.4