Re: kernel panic: Attempted to kill init! (2)

[Dmitry Vyukov]

On Thu, Dec 28, 2017 at 10:20 AM, syzbot
<syzbot+bab350dcd3afb1945f4b@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> Hello,
>
> syzkaller hit the following crash on
> 6084b576dca2e898f5c101baef151f7bfdbb606d
> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
> compiler: gcc (GCC) 7.1.1 20170620
> .config is attached
> Raw console output is attached.
> syzkaller reproducer is attached. See https://goo.gl/kgGztJ
> for information about syzkaller reproducers
>
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+bab350dcd3afb1945f4b@xxxxxxxxxxxxxxxxxxxxxxxxx
> It will help syzbot understand when the bug is fixed. See footer for
> details.
> If you forward the report, please keep this part and the footer.
>
> Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
>
> CPU: 1 PID: 1 Comm: init Not tainted 4.15.0-rc3-next-20171214+ #67
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Call Trace:
>  __dump_stack lib/dump_stack.c:17 [inline]
>  dump_stack+0xe9/0x14b lib/dump_stack.c:53
>  panic+0x10e/0x2f8 kernel/panic.c:183
>  find_child_reaper kernel/exit.c:578 [inline]
>  forget_original_parent kernel/exit.c:674 [inline]
>  exit_notify kernel/exit.c:710 [inline]
>  do_exit+0x1045/0x1050 kernel/exit.c:889
>  do_group_exit+0x60/0x100 kernel/exit.c:972
>  get_signal+0x36c/0xad0 kernel/signal.c:2337
>  do_signal+0x23/0x670 arch/x86/kernel/signal.c:809
>  exit_to_usermode_loop+0x13c/0x160 arch/x86/entry/common.c:161
>  prepare_exit_to_usermode+0x102/0x110 arch/x86/entry/common.c:195
>  retint_user+0x8/0x18
> RIP: 0033:          (null)
> RSP: 002b:00007ffe8c9df0b0 EFLAGS: 00010286
> RAX: ffffffffffffffff


This is a nasty one. It seems that fuzzer managed to corrupts machine
memory which caused a fault in init:

INIT: PANIC: segmentation violation! sleeping for 30 seconds.
[   19.171696] Kernel panic - not syncing: Attempted to kill init!
exitcode=0x0000000b

I can't reproduce this anymore and it seems to stop happening on syzbot as well.
Let's close this for now and see if it happens in future:

#syz invalid



> ---
> This bug is generated by a dumb bot. It may contain errors.
> See https://goo.gl/tpsmEJ for details.
> Direct all questions to syzkaller@xxxxxxxxxxxxxxxxx
>
> syzbot will keep track of this bug report.
> If you forgot to add the Reported-by tag, once the fix for this bug is
> merged
> into any tree, please reply to this email with:
> #syz fix: exact-commit-title
> If you want to test a patch for this bug, please reply with:
> #syz test: git://repo/address.git branch
> and provide the patch inline or as an attachment.
> To mark this as a duplicate of another syzbot report, please reply with:
> #syz dup: exact-subject-of-another-report
> If it's a one-off invalid bug report, please reply with:
> #syz invalid
> Note: if the crash happens again, it will cause creation of a new bug
> report.
> Note: all commands must start from beginning of the line in the email body.
>
> --
> You received this message because you are subscribed to the Google Groups
> "syzkaller-bugs" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to syzkaller-bugs+unsubscribe@xxxxxxxxxxxxxxxxx
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/syzkaller-bugs/001a1140792a4926cf05616305e6%40google.com.
> For more options, visit https://groups.google.com/d/optout.