On 2018/12/31 16:49, Dmitry Vyukov wrote:

On Mon, Dec 31, 2018 at 8:42 AM syzbot
[off-list ref] wrote:

quoted

Hello,

syzbot found the following crash on:

HEAD commit:    ef4ab8447aa2 selftests: bpf: install script with_addr.sh
git tree:       bpf-next
console output: https://syzkaller.appspot.com/x/log.txt?x=14a28b6e400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=7e7e2279c0020d5f
dashboard link: https://syzkaller.appspot.com/bug?extid=ea7d9cb314b4ab49a18a
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+ea7d9cb314b4ab49a18a@syzkaller.appspotmail.com

Since this involves OOMs and looks like a one-off induced memory corruption:

#syz dup: kernel panic: corrupted stack end in wb_workfn

Why?

RCU stall in this case is likely to be latency caused by flooding of printk().