On Wed, Jul 18, 2018 at 2:53 PM, Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> wrote: > On 2018/07/18 20:41, Dmitry Vyukov wrote: >> This seems to be related to 9p. After rerunning the log I got: >> >> root@syzkaller:~# ps afxu | grep syz >> root 18253 0.0 0.0 0 0 ttyS0 Zl 10:16 0:00 \_ >> [syz-executor] <defunct> >> root@syzkaller:~# cat /proc/18253/task/*/stack >> [<0>] p9_client_rpc+0x3a2/0x1400 >> [<0>] p9_client_flush+0x134/0x2a0 >> [<0>] p9_client_rpc+0x122c/0x1400 >> [<0>] p9_client_create+0xc56/0x16af >> [<0>] v9fs_session_init+0x21a/0x1a80 >> [<0>] v9fs_mount+0x7c/0x900 >> [<0>] mount_fs+0xae/0x328 >> [<0>] vfs_kern_mount.part.34+0xdc/0x4e0 >> [<0>] do_mount+0x581/0x30e0 >> [<0>] ksys_mount+0x12d/0x140 >> [<0>] __x64_sys_mount+0xbe/0x150 >> [<0>] do_syscall_64+0x1b9/0x820 >> [<0>] entry_SYSCALL_64_after_hwframe+0x49/0xbe >> [<0>] 0xffffffffffffffff >> >> There is a bunch of hangs in 9p, so let's do: >> >> #syz dup: INFO: task hung in flush_work >> > Then, is dumping all threads when khungtaskd fires a candidate > for CONFIG_DEBUG_AID_FOR_SYZBOT=y path? Perhaps would be useful. But maybe only tasks that are blocked for more than timeout/2? and/or unkillable tasks? killable tasks are not a problem. Btw, I see that p9_client_rpc uses wait_event_killable, why wasn't it killed along with the whole process?
