Message-ID: <000000000000f2d59c05b2eb22e0@google.com>
Date:   Fri, 30 Oct 2020 15:44:16 -0700
From:   syzbot <syzbot+938b0fd3a48bf32ef1f1@...kaller.appspotmail.com>
To:     agruenba@...hat.com, cluster-devel@...hat.com,
        linux-kernel@...r.kernel.org, rpeterso@...hat.com,
        syzkaller-bugs@...glegroups.com
Subject: INFO: task hung in gfs2_gl_hash_clear

Hello,

syzbot found the following issue on:

HEAD commit:    07e08873 Merge tag 'fallthrough-fixes-clang-5.10-rc2' of g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11483132500000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cb6c2acf60eb5bfd
dashboard link: https://syzkaller.appspot.com/bug?extid=938b0fd3a48bf32ef1f1
compiler:       gcc (GCC) 10.1.0-syz 20200507

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+938b0fd3a48bf32ef1f1@...kaller.appspotmail.com

INFO: task syz-executor.0:12142 blocked for more than 143 seconds.
      Not tainted 5.10.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0  state:D stack:25896 pid:12142 ppid:  8475 flags:0x00004004
Call Trace:
 context_switch kernel/sched/core.c:3774 [inline]
 __schedule+0x893/0x2130 kernel/sched/core.c:4523
 schedule+0xcf/0x270 kernel/sched/core.c:4601
 schedule_timeout+0x148/0x250 kernel/time/timer.c:1876
 gfs2_gl_hash_clear+0x240/0x270 fs/gfs2/glock.c:1989
 gfs2_fill_super+0x1e81/0x23f0 fs/gfs2/ops_fstype.c:1233
 get_tree_bdev+0x421/0x740 fs/super.c:1344
 gfs2_get_tree+0x4a/0x270 fs/gfs2/ops_fstype.c:1256
 vfs_get_tree+0x89/0x2f0 fs/super.c:1549
 do_new_mount fs/namespace.c:2875 [inline]
 path_mount+0x13ad/0x20c0 fs/namespace.c:3205
 do_mount fs/namespace.c:3218 [inline]
 __do_sys_mount fs/namespace.c:3426 [inline]
 __se_sys_mount fs/namespace.c:3403 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3403
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x46090a
Code: Unable to access opcode bytes at RIP 0x4608e0.
RSP: 002b:00007f9ee56a8a88 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f9ee56a8b20 RCX: 000000000046090a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f9ee56a8ae0
RBP: 00007f9ee56a8ae0 R08: 00007f9ee56a8b20 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000020000000
R13: 0000000020000100 R14: 0000000020000200 R15: 0000000020047a20

Showing all locks held in the system:
2 locks held by kworker/u4:1/21:
1 lock held by khungtaskd/1643:
 #0: ffffffff8b337060 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6259
1 lock held by systemd-journal/4882:
1 lock held by in:imklog/8120:
 #0: ffff8880134e75f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:932
1 lock held by syz-executor.0/12142:
 #0: ffff88805df5c0e0 (&type->s_umount_key#62/1){+.+.}-{3:3}, at: alloc_super+0x1b8/0xa80 fs/super.c:229

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 1643 Comm: khungtaskd Not tainted 5.10.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline]
 watchdog+0xd43/0xfa0 kernel/hung_task.c:295
 kthread+0x3af/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4882 Comm: systemd-journal Not tainted 5.10.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0033:0x7f3f056c561d
Code: f9 79 f1 ff 83 f8 06 0f 8e bd fd ff ff 48 83 ec 08 4c 8d 0d 6d a1 02 00 4c 8d 05 ae fe 03 00 53 b9 1e 03 00 00 e9 eb fe ff ff <49> 83 f8 10 75 0c 49 89 45 00 45 31 e4 e9 94 fd ff ff 31 d2 4d 89
RSP: 002b:00007ffe73800a50 EFLAGS: 00000246
RAX: 00007f3f02e08798 RBX: 00000000002b2798 RCX: 0000000000000040
RDX: 0000000000000001 RSI: 00007f3f05705480 RDI: 000056506c959140
RBP: 000056506c958ea0 R08: 0000000000000065 R09: 000056506c959140
R10: c68c15b713e34dde R11: 836311406455d5a5 R12: 0000000000000001
R13: 00007ffe73800ac8 R14: 0000000000000000 R15: 00007ffe73800a50
FS:  00007f3f059d68c0 GS:  0000000000000000


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