From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f72.google.com (mail-pg0-f72.google.com [74.125.83.72]) by kanga.kvack.org (Postfix) with ESMTP id 5B67C6B0069 for ; Mon, 15 Jan 2018 09:01:01 -0500 (EST) Received: by mail-pg0-f72.google.com with SMTP id w186so7776623pgb.10 for ; Mon, 15 Jan 2018 06:01:01 -0800 (PST) Received: from mail-sor-f41.google.com (mail-sor-f41.google.com. [209.85.220.41]) by mx.google.com with SMTPS id p3sor4602670pgs.373.2018.01.15.06.01.00 for (Google Transport Security); Mon, 15 Jan 2018 06:01:00 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <201801152256.HDH17623.tSJHFLFOFMVOQO@I-love.SAKURA.ne.jp> References: <201801081948.HAE82801.FQOSHtMOFVLFOJ@I-love.SAKURA.ne.jp> <201801151944.FII09821.FMVQFJtHOOOSLF@I-love.SAKURA.ne.jp> <201801152256.HDH17623.tSJHFLFOFMVOQO@I-love.SAKURA.ne.jp> From: Dmitry Vyukov Date: Mon, 15 Jan 2018 15:00:39 +0100 Message-ID: Subject: Re: INFO: task hung in filemap_fault Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Tetsuo Handa Cc: syzbot , Andi Kleen , Andrew Morton , Jan Kara , jlayton@redhat.com, LKML , Linux-MM , Mel Gorman , Ingo Molnar , npiggin@gmail.com, rgoldwyn@suse.com, syzkaller-bugs@googlegroups.com, Jens Axboe , Ming Lei , Hannes Reinecke , Omar Sandoval , shli@fb.com On Mon, Jan 15, 2018 at 2:56 PM, Tetsuo Handa wrote: > Dmitry Vyukov wrote: >> > No problem. In the "tty: User triggerable soft lockup." case, I manually >> > trimmed the reproducer at https://marc.info/?l=linux-mm&m=151368630414963 . >> > That is, >> > >> > (1) Can the problem be reproduced even if setup_tun(0, true); is commented out? >> > >> > (2) Can the problem be reproduced even if NONFAILING(A = B); is replaced with >> > plain A = B; assignment? >> > >> > (3) Can the problem be reproduced even if install_segv_handler(); is commented >> > out? >> > >> > (4) Can the problem be reproduced even if some syscalls (e.g. __NR_memfd_create, >> > __NR_getsockopt, __NR_perf_event_open) are replaced with no-op? >> > >> > and so on. Then, I finally reached a reproducer which I sent, and the bug was fixed. >> > >> > What is important is that everyone can try simplifying the reproducer written >> > in plain C in order to narrow down the culprit. Providing a (e.g.) CGI service >> > which generates plain C reproducer like gistfile1.txt will be helpful to me. >> >> I am not completely following. You previously mentioned raw.log, which >> is a collection of multiple programs, but now you seem to be talking >> about a single reproducer. When syzbot manages to reproduce the bug >> only with syzkaller program but not with a corresponding C program, it >> provides only syzkaller program. It such case it can sense to convert. >> But the case you pointed to actually contains C program. So there is >> no need to do the conversion at all... What am I missing? >> > > raw.log is not readable for me. > I want to see C program even if syzbot did not manage to reproduce the bug. > If C program is available, everyone can try reproducing the bug with manually > trimmed C program. If it did not manage to reproduce the bug, there is no C program. There is no program at all. -- 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