From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ot0-f199.google.com (mail-ot0-f199.google.com [74.125.82.199]) by kanga.kvack.org (Postfix) with ESMTP id AA9906B0299 for ; Mon, 8 Jan 2018 05:48:41 -0500 (EST) Received: by mail-ot0-f199.google.com with SMTP id g59so6120382otg.3 for ; Mon, 08 Jan 2018 02:48:41 -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 99si3301028otn.113.2018.01.08.02.48.39 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 08 Jan 2018 02:48:40 -0800 (PST) Subject: Re: INFO: task hung in filemap_fault From: Tetsuo Handa References: <001a11444d0e7bfd7f05609956c6@google.com> <82d89066-7dd2-12fe-3cc0-c8d624fe0d51@I-love.SAKURA.ne.jp> <201801020027.GIG26598.OFSMVLQtFHJOOF@I-love.SAKURA.ne.jp> In-Reply-To: Message-Id: <201801081948.HAE82801.FQOSHtMOFVLFOJ@I-love.SAKURA.ne.jp> Date: Mon, 8 Jan 2018 19:48:16 +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: > >> Hi Tetsuo, > >> > >> syzbot always re-runs the same workload on a new machine. If it > >> manages to reproduce the problem, it provides a reproducer. In this > >> case it didn't. > > > > Even if it did not manage to reproduce the problem, showing raw.log in > > C format is helpful for me. For example, > > > > ioctl$LOOP_CHANGE_FD(r3, 0x4c00, r1) > > > > is confusing. 0x4c00 is not LOOP_CHANGE_FD but LOOP_SET_FD. > > If the message were > > > > ioctl(r3, 0x4c00, r1) > > > > more people will be able to read what the program tried to do. > > There are many operations done on loop devices, but are too hard > > for me to pick up only loop related actions. > > > Hi Tetsuo, > > The main purpose of this format is different, this is a complete > representation of programs that allows replaying them using syzkaller > tools. What is ioctl$LOOP_CHANGE_FD(r3, 0x4c00, r1) ? 0x4c00 is LOOP_SET_FD. Why LOOP_CHANGE_FD is there? > We can't simply drop info from there. Do you propose to add > another attached file that contains the same info in a different > format? What is the exact format you are proposing? Plain C program which can be compiled without installing additional program/library packages (except those needed for building kernels). > Is it just > dropping the syscall name part after $ sign? Note that it's still not > C, more complex syscall generally look as follows: > > perf_event_open(&(0x7f0000b5a000)={0x4000000002, 0x78, 0x1e2, 0x0, > 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0xffff, 0x0, > 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, > 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, > @perf_bp={&(0x7f0000000000)=0x0, 0x0}, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, > 0x0, 0x0}, 0x0, 0x0, 0xffffffffffffffff, 0x0) > recvmmsg(0xffffffffffffffff, &(0x7f0000003000)=[{{0x0, 0x0, > &(0x7f0000002000)=[{&(0x7f000000a000)=""/193, 0xc1}, > {&(0x7f0000007000-0x3d)=""/61, 0x3d}], 0x2, > &(0x7f0000005000-0x67)=""/103, 0x67, 0x0}, 0x0}], 0x1, 0x0, > &(0x7f0000003000-0x10)={0x77359400, 0x0}) > bpf$PROG_LOAD(0x5, &(0x7f0000000000)={0x1, 0x5, > &(0x7f0000002000)=@framed={{0x18, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, > 0x0}, [@jmp={0x5, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}], {0x95, 0x0, 0x0, > 0x0}}, &(0x7f0000004000-0xa)='syzkaller\x00', 0x3, 0xc3, > &(0x7f0000386000)=""/195, 0x0, 0x0, [0x0, 0x0, 0x0, 0x0, 0x0, 0x0, > 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0], 0x0}, 0x48) > > Note: you can convert any syzkaller program to equivalent C code using > syz-prog2c utility that comes with syzkaller. I won't install go language into my environment for analyzing/reproducing your reports. If syz-prog2c is provided as a CGI service (e.g. receive URL containing raw.log and print the converted C program), I might try it. -- 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