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[202.181.97.72]) by mx.google.com with ESMTPS id w12si679689otk.230.2019.03.20.03.25.01 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 20 Mar 2019 03:25:01 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of penguin-kernel@i-love.sakura.ne.jp designates 202.181.97.72 as permitted sender) client-ip=202.181.97.72; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of penguin-kernel@i-love.sakura.ne.jp designates 202.181.97.72 as permitted sender) smtp.mailfrom=penguin-kernel@i-love.sakura.ne.jp Received: from fsav301.sakura.ne.jp (fsav301.sakura.ne.jp [153.120.85.132]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id x2KAO3Sr008946; Wed, 20 Mar 2019 19:24:03 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav301.sakura.ne.jp (F-Secure/fsigk_smtp/530/fsav301.sakura.ne.jp); Wed, 20 Mar 2019 19:24:03 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/530/fsav301.sakura.ne.jp) Received: from [192.168.1.8] (softbank126094122116.bbtec.net [126.94.122.116]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id x2KANxPp008907 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NO); Wed, 20 Mar 2019 19:24:03 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Subject: Re: kernel panic: corrupted stack end in wb_workfn To: Dmitry Vyukov , Andrey Ryabinin Cc: syzbot , Andrew Morton , Qian Cai , David Miller , guro@fb.com, Johannes Weiner , Josef Bacik , Kirill Tkhai , LKML , Linux-MM , linux-sctp@vger.kernel.org, Mel Gorman , Michal Hocko , netdev , Neil Horman , Shakeel Butt , syzkaller-bugs , Al Viro , Vladislav Yasevich , Matthew Wilcox , Xin Long References: <000000000000db3d130584506672@google.com> From: Tetsuo Handa Message-ID: <426293c3-bf63-88ad-06fb-83927ab0d7c0@I-love.SAKURA.ne.jp> Date: Wed, 20 Mar 2019 19:23:58 +0900 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.5.3 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit 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: On 2019/03/20 18:59, Dmitry Vyukov wrote: >> From bisection log: >> >> testing release v4.17 >> testing commit 29dcea88779c856c7dc92040a0c01233263101d4 with gcc (GCC) 8.1.0 >> run #0: crashed: kernel panic: corrupted stack end in wb_workfn >> run #1: crashed: kernel panic: corrupted stack end in worker_thread >> run #2: crashed: kernel panic: Out of memory and no killable processes... >> run #3: crashed: kernel panic: corrupted stack end in wb_workfn >> run #4: crashed: kernel panic: corrupted stack end in wb_workfn >> run #5: crashed: kernel panic: corrupted stack end in wb_workfn >> run #6: crashed: kernel panic: corrupted stack end in wb_workfn >> run #7: crashed: kernel panic: corrupted stack end in wb_workfn >> run #8: crashed: kernel panic: Out of memory and no killable processes... >> run #9: crashed: kernel panic: corrupted stack end in wb_workfn >> testing release v4.16 >> testing commit 0adb32858b0bddf4ada5f364a84ed60b196dbcda with gcc (GCC) 8.1.0 >> run #0: OK >> run #1: OK >> run #2: OK >> run #3: OK >> run #4: OK >> run #5: crashed: kernel panic: Out of memory and no killable processes... >> run #6: OK >> run #7: crashed: kernel panic: Out of memory and no killable processes... >> run #8: OK >> run #9: OK >> testing release v4.15 >> testing commit d8a5b80568a9cb66810e75b182018e9edb68e8ff with gcc (GCC) 8.1.0 >> all runs: OK >> # git bisect start v4.16 v4.15 >> >> Why bisect started between 4.16 4.15 instead of 4.17 4.16? > > Because 4.16 was still crashing and 4.15 was not crashing. 4.15..4.16 > looks like the right range, no? No, syzbot should bisect between 4.16 and 4.17 regarding this bug, for "Stack corruption" can't manifest as "Out of memory and no killable processes". "kernel panic: Out of memory and no killable processes..." is completely unrelated to "kernel panic: corrupted stack end in wb_workfn".