On Mon, Nov 5, 2018 at 4:03 AM, Miklos Szeredi <miklos@xxxxxxxxxx> wrote: > On Mon, Nov 5, 2018 at 11:40 AM, Miklos Szeredi <miklos@xxxxxxxxxx> wrote: >> On Thu, Nov 1, 2018 at 12:05 PM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: >>> On Thu, Nov 1, 2018 at 11:49 AM, syzbot >>> <syzbot+6339eda9cb4ebbc4c37b@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: >>>> Hello, >>>> >>>> syzbot found the following crash on: >>>> >>>> HEAD commit: 59fc453b21f7 Merge branch 'akpm' (patches from Andrew) >>>> git tree: upstream >>>> console output: https://syzkaller.appspot.com/x/log.txt?x=15fb2447400000 >>>> kernel config: https://syzkaller.appspot.com/x/.config?x=ea045471e4c756e8 >>>> dashboard link: https://syzkaller.appspot.com/bug?extid=6339eda9cb4ebbc4c37b >>>> compiler: gcc (GCC) 8.0.1 20180413 (experimental) >>>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=178a105d400000 >>>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16651133400000 >>> >>> >>> I can easily reproduce this. >> >> I can't reproduce on my meager dual core notebook. >> >>> >>> The repro gives me a task hanged at: >>> >>> # cat /proc/7563/task/*/stack >>> [<0>] fuse_wait_aborted+0x20b/0x320 >>> [<0>] fuse_sb_destroy+0xe2/0x1d0 >>> [<0>] fuse_kill_sb_anon+0x15/0x20 >>> [<0>] deactivate_locked_super+0x97/0x100 >>> [<0>] deactivate_super+0x2bb/0x320 >>> [<0>] cleanup_mnt+0xbf/0x160 >>> [<0>] __cleanup_mnt+0x16/0x20 >>> [<0>] task_work_run+0x1e8/0x2a0 >>> [<0>] exit_to_usermode_loop+0x318/0x380 >>> [<0>] do_syscall_64+0x6be/0x820 >>> [<0>] entry_SYSCALL_64_after_hwframe+0x49/0xbe >>> [<0>] 0xffffffffffffffff >>> >>> I double checked that writing to /sys/fs/fuse/connections/44/abort did >>> not help (the only entry in fuse/connections). Wrote multiple times, >>> and tried to kill the task, nothing helps. >> >> What's the output of >> >> cat /sys/fs/fuse/connections/NN/waiting >> >> ? > > I think I found the culprit. Does the attached patch fix it? Hi Miklos, I am travelling for next weeks, but you can ask syzbot to test any patches: https://github.com/google/syzkaller/blob/master/docs/syzbot.md#testing-patches
