On Wed, Jan 24, 2018 at 8:39 AM, Johannes Berg
[off-list ref] wrote:

On Mon, 2018-01-22 at 23:39 -0800, syzbot wrote:

quoted

Hello,

syzbot hit the following crash on upstream commit
0d665e7b109d512b7cae3ccef6e8654714887844 (Fri Jan 19 12:49:24 2018 +0000)
mm, page_vma_mapped: Drop faulty pointer arithmetics in check_pte()

So far this crash happened 23 times on net-next, upstream.
C reproducer is attached.
syzkaller reproducer is attached.
Raw console output is attached.
compiler: gcc (GCC) 7.1.1 20170620
.config is attached.
user-space arch: i386

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+41cdaf4232c50e658934@syzkaller.appspotmail.com
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.

------------[ cut here ]------------
workqueue: WQ_MEM_RECLAIM hwsim_wq:destroy_radio is
flushing !WQ_MEM_RECLAIM events_highpri:flush_backlog
WARNING: CPU: 0 PID: 3706 at kernel/workqueue.c:2439
check_flush_dependency+0x239/0x380 kernel/workqueue.c:2435
Kernel panic - not syncing: panic_on_warn set ...

Yeah, we clearly shouldn't have WQ_RECLAIM set on this workqueue...

Hi Johannes,

Do you mind to send a patch to fix this?