syzbot


INFO: task hung in xlog_grant_head_check

Status: upstream: reported C repro on 2020/02/10 12:53
Reported-by: syzbot+79bf1b7904386a38a51a@syzkaller.appspotmail.com
First crash: 916d, last: 763d

Fix bisection: the fix commit could be any of (bisect log):
  78d697fc93f9 Linux 4.14.172
  4139fb08c05f Linux 4.14.187
similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in xlog_grant_head_check C done error 37 759d 1546d 0/23 upstream: reported C repro on 2018/05/21 17:55
linux-4.19 INFO: task hung in xlog_grant_head_check 1 1145d 1145d 0/1 auto-closed as invalid on 2019/10/25 08:51
linux-4.19 INFO: task hung in xlog_grant_head_check (2) 3 786d 835d 0/1 auto-closed as invalid on 2020/10/17 16:39

Sample crash report:
ffff88809ad50820: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
ffff88809ad50830: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
XFS (loop0): metadata I/O error: block 0x1 ("xfs_trans_read_buf_map") error 117 numblks 1
INFO: task syz-executor836:7511 blocked for more than 140 seconds.
      Not tainted 4.14.172-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor836 D27936  7511   7509 0x00000000
Call Trace:
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 xlog_grant_head_wait+0x135/0xc10 fs/xfs/xfs_log.c:274
 xlog_grant_head_check+0x34c/0x390 fs/xfs/xfs_log.c:336
 xfs_log_reserve+0x2fb/0x9f0 fs/xfs/xfs_log.c:465
 xfs_log_unmount_write fs/xfs/xfs_log.c:857 [inline]
 xfs_log_quiesce+0x2ec/0x980 fs/xfs/xfs_log.c:983
 xfs_log_unmount+0x1d/0xb0 fs/xfs/xfs_log.c:997
 xfs_log_mount_cancel+0x40/0x50 fs/xfs/xfs_log.c:800
 xfs_mountfs+0x1192/0x1f10 fs/xfs/xfs_mount.c:1031
 xfs_fs_fill_super+0xb7a/0x1380 fs/xfs/xfs_super.c:1688
 mount_bdev+0x2bc/0x370 fs/super.c:1134
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x3c0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x3c9/0x24f0 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xa8/0x120 fs/namespace.c:3072
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x44761a
RSP: 002b:00007ffc663d27d8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffc663d29b0 RCX: 000000000044761a
RDX: 00007ffc663d2820 RSI: 0000000020000000 RDI: 00007ffc663d2840
RBP: 0000000000000000 R08: 00007ffc663d2880 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000402900
R13: 0000000000402990 R14: 0000000000000000 R15: 0000000000000000

Showing all locks held in the system:
1 lock held by khungtaskd/1054:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffff81465b23>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4544
1 lock held by rsyslogd/7367:
 #0:  (&f->f_pos_lock){+.+.}, at: [<ffffffff8191b3b6>] __fdget_pos+0xa6/0xc0 fs/file.c:769
2 locks held by getty/7490:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833aa792>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8339e3d4>] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156
2 locks held by getty/7491:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833aa792>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8339e3d4>] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156
2 locks held by getty/7492:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833aa792>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8339e3d4>] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156
2 locks held by getty/7493:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833aa792>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8339e3d4>] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156
2 locks held by getty/7494:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833aa792>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8339e3d4>] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156
2 locks held by getty/7495:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833aa792>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8339e3d4>] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156
2 locks held by getty/7496:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833aa792>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8339e3d4>] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156
1 lock held by syz-executor836/7511:
 #0:  (&type->s_umount_key#51/1){+.+.}, at: [<ffffffff818baa56>] alloc_super fs/super.c:251 [inline]
 #0:  (&type->s_umount_key#51/1){+.+.}, at: [<ffffffff818baa56>] sget_userns+0x556/0xc30 fs/super.c:516

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

NMI backtrace for cpu 0
CPU: 0 PID: 1054 Comm: khungtaskd Not tainted 4.14.172-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x13e/0x194 lib/dump_stack.c:58
 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x139/0x17e lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
 watchdog+0x5e2/0xb80 kernel/hung_task.c:274
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff86401cbe

Crashes (7):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2020/03/10 01:05 linux-4.14.y 78d697fc93f9 35f53e45 .config log report syz C
ci2-linux-4-14 2020/02/10 14:36 linux-4.14.y e0f8b8a65a47 35f5e45e .config log report syz C
ci2-linux-4-14 2020/07/12 22:44 linux-4.14.y b850307b279c 9ebcc5b1 .config log report
ci2-linux-4-14 2020/05/04 06:56 linux-4.14.y 773e2b1cd56a 58ae5e18 .config log report
ci2-linux-4-14 2020/04/23 12:38 linux-4.14.y c10b57a567e4 2e44d63e .config log report
ci2-linux-4-14 2020/04/07 20:43 linux-4.14.y 4520f06b03ae db9bcd4b .config log report
ci2-linux-4-14 2020/02/10 12:52 linux-4.14.y e0f8b8a65a47 35f5e45e .config log report