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From: Tetsuo Handa <>
To: Dmitry Vyukov <>
Cc: syzbot <>,
	David Miller <>,
	Alexey Kuznetsov <>,
	LKML <>,
	netdev <>,
	syzkaller-bugs <>,
	Hideaki YOSHIFUJI <>,
	Linux-MM <>, Shakeel Butt <>,
	syzkaller <>
Subject: Re: INFO: rcu detected stall in ndisc_alloc_skb
Date: Sat, 19 Jan 2019 22:10:22 +0900	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On 2019/01/19 21:16, Dmitry Vyukov wrote:
>> The question for me is, whether sysbot can detect hash collision with different
>> syz-program lines before writing the hash value to /dev/kmsg, and retry by modifying
>> syz-program lines in order to get a new hash value until collision is avoided.
>> If it is difficult, simpler choice like current Unix time and PID could be used
>> instead...
> Hummm, say, if you run syz-manager locally and report a bug, where
> will the webserver and database that allows to download all satellite
> info work? How long you need to keep this info and provide the web
> service? You will also need to pay and maintain the server for... how
> long? I don't see how this can work and how we can ask people to do
> this. This frankly looks like overly complex solution to a problem
> were simpler solutions will work. Keeping all info in a self-contained
> file looks like the only option to make it work reliably.
> It's also not possible to attribute kernel output to individual programs.

The first messages I want to look at is kernel output. Then, I look at
syz-program lines as needed. But current "a self-contained file" is
hard to find kernel output. Even if we keep both kernel output and
syz-program lines in a single file, we can improve readability by
splitting into kernel output section and syz-program section.

  # Kernel output section start
  [$(uptime)][$(caller_info)] executing program #0123456789abcdef0123456789abcdef
  [$(uptime)][$(caller_info)] $(kernel_messages_caused_by_0123456789abcdef0123456789abcdef_are_here)
  [$(uptime)][$(caller_info)] executing program #456789abcdef0123456789abcdef0123
  [$(uptime)][$(caller_info)] $(kernel_messages_caused_by_456789abcdef0123456789abcdef0123_and_0123456789abcdef0123456789abcdef_are_here)
  [$(uptime)][$(caller_info)] executing program #89abcdef0123456789abcdef01234567
  [$(uptime)][$(caller_info)] $(kernel_messages_caused_by_89abcdef0123456789abcdef01234567_456789abcdef0123456789abcdef0123_and_0123456789abcdef0123456789abcdef_are_here)
  [$(uptime)][$(caller_info)] BUG: unable to handle kernel paging request at $(address)
  [$(uptime)][$(caller_info)] CPU: $(cpu) PID: $(pid) Comm: syz#89abcdef0123 Not tainted $(version) #$(build)
  [$(uptime)][$(caller_info)] $(backtrace_of_caller_info_is_here)
  [$(uptime)][$(caller_info)] Kernel panic - not syncing: Fatal exception
  # Kernel output section end
  # syzbot code section start
  Program for #0123456789abcdef0123456789abcdef
  Program for #456789abcdef0123456789abcdef0123
  Program for #89abcdef0123456789abcdef01234567
  # syzbot code section end

  reply	other threads:[~2019-01-19 13:11 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-31  7:42 syzbot
2018-12-31  7:49 ` Dmitry Vyukov
2018-12-31  7:49   ` Dmitry Vyukov
2018-12-31  8:17   ` Tetsuo Handa
2018-12-31  8:24     ` Dmitry Vyukov
2018-12-31  8:24       ` Dmitry Vyukov
2019-01-02 17:06       ` Tetsuo Handa
2019-01-05 10:49         ` Tetsuo Handa
2019-01-06 13:24           ` Dmitry Vyukov
2019-01-06 13:24             ` Dmitry Vyukov
2019-01-06 13:47             ` Tetsuo Handa
2019-01-07 11:12               ` Dmitry Vyukov
2019-01-07 11:12                 ` Dmitry Vyukov
2019-01-18  5:20                 ` Tetsuo Handa
2019-01-19 12:16                   ` Dmitry Vyukov
2019-01-19 12:16                     ` Dmitry Vyukov
2019-01-19 13:10                     ` Tetsuo Handa [this message]
2019-01-20 13:30                       ` Dmitry Vyukov
2019-01-20 13:30                         ` Dmitry Vyukov
2019-01-20 14:24                         ` Tetsuo Handa

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