From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f69.google.com (mail-oi0-f69.google.com [209.85.218.69]) by kanga.kvack.org (Postfix) with ESMTP id 751266B0038 for ; Mon, 15 Jan 2018 09:38:45 -0500 (EST) Received: by mail-oi0-f69.google.com with SMTP id d28so7180720oic.15 for ; Mon, 15 Jan 2018 06:38:45 -0800 (PST) Received: from www262.sakura.ne.jp (www262.sakura.ne.jp. [2001:e42:101:1:202:181:97:72]) by mx.google.com with ESMTPS id d4si3382098oib.523.2018.01.15.06.38.44 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 15 Jan 2018 06:38:44 -0800 (PST) Subject: Re: INFO: task hung in filemap_fault From: Tetsuo Handa References: <201801152256.HDH17623.tSJHFLFOFMVOQO@I-love.SAKURA.ne.jp> <201801152325.FGE87548.tSLMFOVHFJOFQO@I-love.SAKURA.ne.jp> In-Reply-To: Message-Id: <201801152338.EBJ73933.FLSJHFVtOFOOQM@I-love.SAKURA.ne.jp> Date: Mon, 15 Jan 2018 23:38:26 +0900 Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-linux-mm@kvack.org List-ID: To: dvyukov@google.com Cc: bot+980f5e5fc060c37505bd65abb49a963518b269d9@syzkaller.appspotmail.com, ak@linux.intel.com, akpm@linux-foundation.org, jack@suse.cz, jlayton@redhat.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mgorman@techsingularity.net, mingo@kernel.org, npiggin@gmail.com, rgoldwyn@suse.com, syzkaller-bugs@googlegroups.com, axboe@kernel.dk, tom.leiming@gmail.com, hare@suse.de, osandov@fb.com, shli@fb.com Dmitry Vyukov wrote: > On Mon, Jan 15, 2018 at 3:25 PM, Tetsuo Handa > wrote: > > Dmitry Vyukov wrote: > >> >> 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. > >> > > > > What!? Then, what does raw.log contain? I want to read raw.log as C program. > > > raw.log is not a _program_, it's hundreds of separate programs that > were executed before the crash. I want to know the hundreds of separate programs as C programs. Even if there are hundreds, more recently ran programs tend to be the culprit. > It's also very compressed > representation as compared to equivalent C programs. For example for > this program: > > mmap(&(0x7f0000000000/0xfff000)=nil, 0xfff000, 0x3, 0x32, > 0xffffffffffffffff, 0x0) > r0 = socket$nl_generic(0x10, 0x3, 0x10) > sendmsg$nl_generic(r0, > &(0x7f0000b3e000-0x38)={&(0x7f0000d4a000-0xc)={0x10, 0x0, 0x0, 0x0}, > 0xc, &(0x7f0000007000)={&(0x7f0000f7c000-0x15c)={0x24, 0x1c, 0x109, > 0xffffffffffffffff, 0xffffffffffffffff, {0x4, 0x0, 0x0}, > [@nested={0x10, 0x9, [@typed={0xc, 0x0, @u32=0x0}]}]}, 0x24}, 0x1, > 0x0, 0x0, 0x0}, 0x0) > > you can get up to this amount of C code: > https://gist.githubusercontent.com/dvyukov/eeaeb4e4ac45c3a251f72098c9295bf9/raw/700cd583507eca90711ba11b42e406f317553371/gistfile1.txt > > that is, 700 lines of C source for 3 line program. So instead of a 1MB > file that will be 100MB, and then it probably should be a gzip archive > with hundreds of separate C files. There are people on this list > complaining even about 200K of attachments. I don't see that this will > be better and well accepted. > I don't think attaching to mails is acceptable. Thus, I suggest e.g. CGI service so that only those who want to try can obtain the C programs. -- 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