INFO: task hung in __xfs_buf_submit

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syzbot

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May 17, 2020, 4:00:15 AM5/17/20
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Hello,

syzbot found the following crash on:

HEAD commit: ac935d22 Add linux-next specific files for 20200415
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17f6d548100000
kernel config: https://syzkaller.appspot.com/x/.config?x=bc498783097e9019
dashboard link: https://syzkaller.appspot.com/bug?extid=56208db10c09c05320e3
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
CC: [darric...@oracle.com linux-...@vger.kernel.org linu...@vger.kernel.org]

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+56208d...@syzkaller.appspotmail.com

INFO: task syz-executor.2:687 can't die for more than 143 seconds.
syz-executor.2 D26992 687 7316 0x00004004
Call Trace:
schedule+0xd0/0x2a0 kernel/sched/core.c:4163
schedule_timeout+0x55b/0x850 kernel/time/timer.c:1874
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x16a/0x270 kernel/sched/completion.c:138
xfs_buf_iowait+0x8f/0x650 fs/xfs/xfs_buf.c:1458
__xfs_buf_submit+0x47e/0xb00 fs/xfs/xfs_buf.c:1526
xfs_buf_submit fs/xfs/xfs_buf.h:271 [inline]
xfs_buf_read_uncached+0x204/0x5e0 fs/xfs/xfs_buf.c:926
xfs_readsb+0x291/0x4e0 fs/xfs/xfs_mount.c:298
xfs_fc_fill_super+0x49d/0x1310 fs/xfs/xfs_super.c:1398
get_tree_bdev+0x3f8/0x710 fs/super.c:1342
vfs_get_tree+0x89/0x2f0 fs/super.c:1547
do_new_mount fs/namespace.c:2813 [inline]
do_mount+0x1306/0x1b30 fs/namespace.c:3138
__do_sys_mount fs/namespace.c:3347 [inline]
__se_sys_mount fs/namespace.c:3324 [inline]
__x64_sys_mount+0x18f/0x230 fs/namespace.c:3324
do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45c829
Code: Bad RIP value.
RSP: 002b:00007fe4a105dc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000004f6020 RCX: 000000000045c829
RDX: 0000000020000640 RSI: 0000000020000400 RDI: 0000000020000600
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000751 R14: 00000000004ca1aa R15: 00007fe4a105e6d4
INFO: task syz-executor.2:687 blocked for more than 143 seconds.
Not tainted 5.7.0-rc1-next-20200415-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2 D26992 687 7316 0x00004004
Call Trace:
schedule+0xd0/0x2a0 kernel/sched/core.c:4163
schedule_timeout+0x55b/0x850 kernel/time/timer.c:1874
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x16a/0x270 kernel/sched/completion.c:138
xfs_buf_iowait+0x8f/0x650 fs/xfs/xfs_buf.c:1458
__xfs_buf_submit+0x47e/0xb00 fs/xfs/xfs_buf.c:1526
xfs_buf_submit fs/xfs/xfs_buf.h:271 [inline]
xfs_buf_read_uncached+0x204/0x5e0 fs/xfs/xfs_buf.c:926
xfs_readsb+0x291/0x4e0 fs/xfs/xfs_mount.c:298
xfs_fc_fill_super+0x49d/0x1310 fs/xfs/xfs_super.c:1398
get_tree_bdev+0x3f8/0x710 fs/super.c:1342
vfs_get_tree+0x89/0x2f0 fs/super.c:1547
do_new_mount fs/namespace.c:2813 [inline]
do_mount+0x1306/0x1b30 fs/namespace.c:3138
__do_sys_mount fs/namespace.c:3347 [inline]
__se_sys_mount fs/namespace.c:3324 [inline]
__x64_sys_mount+0x18f/0x230 fs/namespace.c:3324
do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45c829
Code: Bad RIP value.
RSP: 002b:00007fe4a105dc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000004f6020 RCX: 000000000045c829
RDX: 0000000020000640 RSI: 0000000020000400 RDI: 0000000020000600
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000751 R14: 00000000004ca1aa R15: 00007fe4a105e6d4
INFO: task syz-executor.2:730 can't die for more than 143 seconds.
syz-executor.2 D28400 730 7316 0x00000004
Call Trace:
schedule+0xd0/0x2a0 kernel/sched/core.c:4163
rwsem_down_write_slowpath+0x6eb/0xf80 kernel/locking/rwsem.c:1235
__down_write kernel/locking/rwsem.c:1389 [inline]
down_write+0x137/0x150 kernel/locking/rwsem.c:1532
grab_super+0xa3/0x260 fs/super.c:389
sget_fc+0x242/0x790 fs/super.c:561
get_tree_bdev+0x1bb/0x710 fs/super.c:1312
vfs_get_tree+0x89/0x2f0 fs/super.c:1547
do_new_mount fs/namespace.c:2813 [inline]
do_mount+0x1306/0x1b30 fs/namespace.c:3138
__do_sys_mount fs/namespace.c:3347 [inline]
__se_sys_mount fs/namespace.c:3324 [inline]
__x64_sys_mount+0x18f/0x230 fs/namespace.c:3324
do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45c829
Code: Bad RIP value.
RSP: 002b:00007fe4a101bc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000004f6020 RCX: 000000000045c829
RDX: 0000000020000640 RSI: 0000000020000400 RDI: 0000000020000600
RBP: 000000000078c040 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000751 R14: 00000000004ca1aa R15: 00007fe4a101c6d4
INFO: task syz-executor.2:730 blocked for more than 144 seconds.
Not tainted 5.7.0-rc1-next-20200415-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2 D28400 730 7316 0x00000004
Call Trace:
schedule+0xd0/0x2a0 kernel/sched/core.c:4163
rwsem_down_write_slowpath+0x6eb/0xf80 kernel/locking/rwsem.c:1235
__down_write kernel/locking/rwsem.c:1389 [inline]
down_write+0x137/0x150 kernel/locking/rwsem.c:1532
grab_super+0xa3/0x260 fs/super.c:389
sget_fc+0x242/0x790 fs/super.c:561
get_tree_bdev+0x1bb/0x710 fs/super.c:1312
vfs_get_tree+0x89/0x2f0 fs/super.c:1547
do_new_mount fs/namespace.c:2813 [inline]
do_mount+0x1306/0x1b30 fs/namespace.c:3138
__do_sys_mount fs/namespace.c:3347 [inline]
__se_sys_mount fs/namespace.c:3324 [inline]
__x64_sys_mount+0x18f/0x230 fs/namespace.c:3324
do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45c829
Code: Bad RIP value.
RSP: 002b:00007fe4a101bc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000004f6020 RCX: 000000000045c829
RDX: 0000000020000640 RSI: 0000000020000400 RDI: 0000000020000600
RBP: 000000000078c040 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000751 R14: 00000000004ca1aa R15: 00007fe4a101c6d4

Showing all locks held in the system:
1 lock held by khungtaskd/1167:
#0: ffffffff899befc0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5754
1 lock held by in:imklog/6783:
#0: ffff8880956d7130 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826
2 locks held by agetty/6939:
#0: ffff8880a6605098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267
#1: ffffc90000f902e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x220/0x1b30 drivers/tty/n_tty.c:2156
1 lock held by syz-executor.2/687:
#0: ffff888091be40e0 (&type->s_umount_key#51/1){+.+.}-{3:3}, at: alloc_super+0x1b3/0x9d0 fs/super.c:229
2 locks held by syz-executor.2/730:
#0: ffff88808a67b850 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x10a/0x710 fs/super.c:1302
#1: ffff888091be40e0 (&type->s_umount_key#66){+.+.}-{3:3}, at: grab_super+0xa3/0x260 fs/super.c:389

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

NMI backtrace for cpu 1
CPU: 1 PID: 1167 Comm: khungtaskd Not tainted 5.7.0-rc1-next-20200415-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+0x188/0x20d lib/dump_stack.c:118
nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x231/0x27e lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:147 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:249 [inline]
watchdog+0xde3/0x14e0 kernel/hung_task.c:333
kthread+0x388/0x470 kernel/kthread.c:268
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4145 Comm: systemd-journal Not tainted 5.7.0-rc1-next-20200415-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0033:0x7fc08308a0e3
Code: 00 00 00 48 8b 48 70 48 c1 e9 04 48 85 c9 0f 84 f2 01 00 00 31 d2 48 89 e8 48 f7 f1 48 c1 e2 04 48 03 93 d0 00 00 00 4c 8b 3a <4d> 85 ff 74 8a 48 8d 44 24 50 4c 8d 64 24 48 48 89 44 24 20 48 8d
RSP: 002b:00007ffe9ecb8a60 EFLAGS: 00000202
RAX: 00008a70ad33b99d RBX: 000055ff35e8be80 RCX: 00000000000118aa
RDX: 00007fc080579f10 RSI: 0000000000000000 RDI: 000055ff35e8be80
RBP: 97c72c43975d59d5 R08: 00007ffe9ecb8b38 R09: 00007ffe9ecb8b40
R10: 00007fc0830b4ee8 R11: 0000000000000246 R12: 000055ff35e8be80
R13: 0000000000000026 R14: 000055ff35e8c0b0 R15: 0000000000000000
FS: 00007fc0833998c0 GS: 0000000000000000


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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syzbot

unread,
Jul 12, 2020, 3:26:09 AM7/12/20
to syzkaller-upst...@googlegroups.com
Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.
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