Re: KASAN: stack-out-of-bounds Read in check_stack_object

[Dmitry Vyukov]

On Sun, Jan 6, 2019 at 3:37 PM Tetsuo Handa
<penguin-kernel@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On 2019/01/06 22:48, Dmitry Vyukov wrote:
> > On Sun, Jan 6, 2019 at 2:31 PM syzbot
> > <syzbot+05fc3a636f5ee8830a99@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> >>
> >> Hello,
> >>
> >> syzbot found the following crash on:
> >>
> >> HEAD commit:    3fed6ae4b027 ia64: fix compile without swiotlb
> >> git tree:       upstream
> >> console output: https://syzkaller.appspot.com/x/log.txt?x=161ce1d7400000
> >> kernel config:  https://syzkaller.appspot.com/x/.config?x=7308e68273924137
> >> dashboard link: https://syzkaller.appspot.com/bug?extid=05fc3a636f5ee8830a99
> >> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> >> userspace arch: i386
> >> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10b3769f400000
> >>
> >> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> >> Reported-by: syzbot+05fc3a636f5ee8830a99@xxxxxxxxxxxxxxxxxxxxxxxxx
> >
> > I suspect this is another incarnation of:
> > https://syzkaller.appspot.com/bug?id=4821de869e3d78a255a034bf212a4e009f6125a7
> > Any other ideas?
>
>
>
> >> CPU: 0 PID: -1455013312 Comm:  Not tainted 4.20.0+ #10
>
> "current->pid < 0" suggests that "struct task_struct" was overwritten.
>
> >> #PF error: [normal kernel read fault]
>
> >> Thread overran stack, or stack corrupted
>
> And "struct task_struct" might be overwritten by stack overrun?
>
> The cause of overrun is unknown, but given that
> "fou6: Prevent unbounded recursion in GUE error handler" is not yet
> applied to linux.git tree, this might be a dup of that bug.


#syz dup: kernel panic: stack is corrupted in udp4_lib_lookup2