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[209.85.220.65]) by mx.google.com with SMTPS id r18sor2328766itb.5.2019.03.11.23.08.50 for (Google Transport Security); Mon, 11 Mar 2019 23:08:51 -0700 (PDT) Received-SPF: pass (google.com: domain of dvyukov@google.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=hqE6AUsr; spf=pass (google.com: domain of dvyukov@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=dvyukov@google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=N1JiQ1cf1uHp+tMakySvUAuKGEi8FGoygCN9wkQMXqw=; b=hqE6AUsrdIaw8AqgtLspHLAVKb5SxCwC13bRoQ+Z0wXsi36QiN13hYYns2oMwfN6qO Pc8GSslcZrTFHx+8t2295LkvYl28Oia+4xOaj0EUqW0xLreRAVcsNOiyvls9FHg5Hitw 5PARefocPhP7I/YbPrPyxPfC518gAUgj23ET9aaCDOrZxUaVlesbZWpGxRwxd7jaE+5J wC0ypf6VGxVCc5XixFadnCaB1n5jJQu6rdgO5eE/wMwWsjUgKM7XGZMcg/8ZXv41k5Oo d8WmszRQ+rfKrZay/cpoqmTHKNlZjsJe0pTj6SN32Dv98bDzjmMIkX6VW08aG7bJB3XT xLWQ== X-Google-Smtp-Source: APXvYqyGXtnMS2ogIjE5olP/bMefqZZmG86bf7yTmNWT6Oi2bSZlY5OSUGoDZnJnkjBP5bwMQsCr5Os3poCp9xG8Zic= X-Received: by 2002:a05:660c:3d1:: with SMTP id c17mr966026itl.166.1552370930231; Mon, 11 Mar 2019 23:08:50 -0700 (PDT) MIME-Version: 1.0 References: <0000000000001fd5780583d1433f@google.com> <20190311163747.f56cceebd9c2661e4519bdfc@linux-foundation.org> In-Reply-To: <20190311163747.f56cceebd9c2661e4519bdfc@linux-foundation.org> From: Dmitry Vyukov Date: Tue, 12 Mar 2019 07:08:38 +0100 Message-ID: Subject: Re: KASAN: null-ptr-deref Read in reclaim_high To: Andrew Morton Cc: syzbot , cgroups@vger.kernel.org, Johannes Weiner , LKML , Linux-MM , Michal Hocko , Michal Hocko , Stephen Rothwell , Shakeel Butt , syzkaller-bugs , Vladimir Davydov Content-Type: text/plain; charset="UTF-8" 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 Tue, Mar 12, 2019 at 12:37 AM Andrew Morton wrote: > > On Mon, 11 Mar 2019 06:08:01 -0700 syzbot wrote: > > > syzbot has bisected this bug to: > > > > commit 29a4b8e275d1f10c51c7891362877ef6cffae9e7 > > Author: Shakeel Butt > > Date: Wed Jan 9 22:02:21 2019 +0000 > > > > memcg: schedule high reclaim for remote memcgs on high_work > > > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=155bf5db200000 > > start commit: 29a4b8e2 memcg: schedule high reclaim for remote memcgs on.. > > git tree: linux-next > > final crash: https://syzkaller.appspot.com/x/report.txt?x=175bf5db200000 > > console output: https://syzkaller.appspot.com/x/log.txt?x=135bf5db200000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=611f89e5b6868db > > dashboard link: https://syzkaller.appspot.com/bug?extid=fa11f9da42b46cea3b4a > > userspace arch: amd64 > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14259017400000 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=141630a0c00000 > > > > Reported-by: syzbot+fa11f9da42b46cea3b4a@syzkaller.appspotmail.com > > Fixes: 29a4b8e2 ("memcg: schedule high reclaim for remote memcgs on > > high_work") > > The following patch > memcg-schedule-high-reclaim-for-remote-memcgs-on-high_work-v3.patch > might have fixed this. Was it applied? Hi Andrew, You mean if the patch was applied during the bisection? No, it wasn't. Bisection is very specifically done on the same tree where the bug was hit. There are already too many factors that make the result flaky/wrong/inconclusive without changing the tree state. Now, if syzbot would know about any pending fix for this bug, then it would not do the bisection at all. But it have not seen any patch in upstream/linux-next with the Reported-by tag, nor it received any syz fix commands for this bugs. Should have been it aware of the fix? How? Thanks