Re: KASAN: use-after-scope Read in __hrtimer_run_queues

[Thomas Gleixner]

On Wed, 4 Jul 2018, syzbot wrote:

> Hello,
> 
> syzbot found the following crash on:
> 
> HEAD commit:    2bdea157b999 Merge branch 'sctp-fully-support-for-dscp-and..
> git tree:       bpf-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=14339f42400000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=f62553dc846b0692
> dashboard link: https://syzkaller.appspot.com/bug?extid=7f73a81393d3b3777fb0
> compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
> 
> Unfortunately, I don't have any reproducer for this crash yet.
> 
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+7f73a81393d3b3777fb0@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> ==================================================================
> BUG: KASAN: use-after-scope in lookup_object lib/debugobjects.c:157 [inline]
> BUG: KASAN: use-after-scope in debug_object_deactivate+0x425/0x450
> lib/debugobjects.c:540
> Read of size 8 at addr ffff88019d1a5ec0 by task syz-executor3/13445

I don't see how lib/debugobjects.c:157 would be a valid use after scope
issue. The one in line 540 makes no sense either.

Thanks,

	tglx