INFO: task hung in __xfs_buf_submit

Status: upstream: reported C repro on 2026/09/05 05:19
Reported-by: syzbot+59be43a9e12b12022dcb@syzkaller.appspotmail.com
First crash: 3d09h, last: 2d22h
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: task hung in __xfs_buf_submit (2) 1 1 15d 15d 0/3 upstream: reported on 2026/08/23 22:24
upstream INFO: task hung in __xfs_buf_submit (2) xfs 1 syz, C done inconclusive 7 1215d 1839d 0/29 auto-obsoleted due to no activity on 2023/08/23 09:04
linux-6.1 INFO: task hung in __xfs_buf_submit 1 8 508d 524d 0/3 auto-obsoleted due to no activity on 2025/07/27 03:12
upstream INFO: task hung in __xfs_buf_submit xfs 1 1 2309d 2305d 0/29 auto-closed as invalid on 2020/07/12 07:26
upstream INFO: task can't die in p9_fd_close 1 syz, C done 58 1597d 2204d 0/29 closed as dup on 2022/08/26 12:44

Sample crash report:
INFO: task syz.2.19:4360 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.19        state:D stack:27184 pid: 4360 ppid:  4309 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2093
 do_wait_for_common+0x295/0x460 kernel/sched/completion.c:85
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
 xfs_buf_iowait+0xae/0x3d0 fs/xfs/xfs_buf.c:1573
 __xfs_buf_submit+0x3b5/0x7b0 fs/xfs/xfs_buf.c:1638
 xfs_buf_submit fs/xfs/xfs_buf.c:58 [inline]
 xfs_buf_read_uncached+0x15d/0x230 fs/xfs/xfs_buf.c:885
 xfs_readsb+0x172/0x630 fs/xfs/xfs_mount.c:178
 xfs_fs_fill_super+0x583/0x13e0 fs/xfs/xfs_super.c:1516
 get_tree_bdev+0x3e6/0x610 fs/super.c:1336
 vfs_get_tree+0x88/0x270 fs/super.c:1541
 do_new_mount+0x247/0xa40 fs/namespace.c:3034
 do_mount fs/namespace.c:3377 [inline]
 __do_sys_mount fs/namespace.c:3585 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f6d8d07e159
RSP: 002b:00007f6d8c6de028 EFLAGS: 00000246
 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f6d8d305fa0 RCX: 00007f6d8d07e159
RDX: 00002000000002c0 RSI: 0000200000000280 RDI: 0000200000000080
RBP: 00007f6d8d115024 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000281841d R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6d8d306038 R14: 00007f6d8d305fa0 R15: 00007ffeec1c30d8
 </TASK>
INFO: task syz.1.22:4376 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.22        state:D stack:27600 pid: 4376 ppid:  4308 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2093
 do_wait_for_common+0x295/0x460 kernel/sched/completion.c:85
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
 xfs_buf_iowait+0xae/0x3d0 fs/xfs/xfs_buf.c:1573
 __xfs_buf_submit+0x3b5/0x7b0 fs/xfs/xfs_buf.c:1638
 xfs_buf_submit fs/xfs/xfs_buf.c:58 [inline]
 xfs_buf_read_uncached+0x15d/0x230 fs/xfs/xfs_buf.c:885
 xfs_readsb+0x172/0x630 fs/xfs/xfs_mount.c:178
 xfs_fs_fill_super+0x583/0x13e0 fs/xfs/xfs_super.c:1516
 get_tree_bdev+0x3e6/0x610 fs/super.c:1336
 vfs_get_tree+0x88/0x270 fs/super.c:1541
 do_new_mount+0x247/0xa40 fs/namespace.c:3034
 do_mount fs/namespace.c:3377 [inline]
 __do_sys_mount fs/namespace.c:3585 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fab36f85159
RSP: 002b:00007fab365e5028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fab3720cfa0 RCX: 00007fab36f85159
RDX: 00002000000002c0 RSI: 0000200000000280 RDI: 0000200000000080
RBP: 00007fab3701c024 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000281841d R11: 0000000000000246 R12: 0000000000000000
R13: 00007fab3720d038 R14: 00007fab3720cfa0 R15: 00007ffdc1bf8278
 </TASK>
INFO: task syz.0.17:4403 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17        state:D stack:27408 pid: 4403 ppid:  4310 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2093
 do_wait_for_common+0x295/0x460 kernel/sched/completion.c:85
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
 xfs_buf_iowait+0xae/0x3d0 fs/xfs/xfs_buf.c:1573
 __xfs_buf_submit+0x3b5/0x7b0 fs/xfs/xfs_buf.c:1638
 xfs_buf_submit fs/xfs/xfs_buf.c:58 [inline]
 xfs_buf_read_uncached+0x15d/0x230 fs/xfs/xfs_buf.c:885
 xfs_readsb+0x172/0x630 fs/xfs/xfs_mount.c:178
 xfs_fs_fill_super+0x583/0x13e0 fs/xfs/xfs_super.c:1516
 get_tree_bdev+0x3e6/0x610 fs/super.c:1336
 vfs_get_tree+0x88/0x270 fs/super.c:1541
 do_new_mount+0x247/0xa40 fs/namespace.c:3034
 do_mount fs/namespace.c:3377 [inline]
 __do_sys_mount fs/namespace.c:3585 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f48c56e3159
RSP: 002b:00007f48c4d43028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f48c596afa0 RCX: 00007f48c56e3159
RDX: 00002000000002c0 RSI: 0000200000000280 RDI: 0000200000000080
RBP: 00007f48c577a024 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000281841d R11: 0000000000000246 R12: 0000000000000000
R13: 00007f48c596b038 R14: 00007f48c596afa0 R15: 00007ffdf4124f88
 </TASK>
INFO: task syz.3.24:4429 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.24        state:D stack:27600 pid: 4429 ppid:  4312 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2093
 do_wait_for_common+0x295/0x460 kernel/sched/completion.c:85
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
 xfs_buf_iowait+0xae/0x3d0 fs/xfs/xfs_buf.c:1573
 __xfs_buf_submit+0x3b5/0x7b0 fs/xfs/xfs_buf.c:1638
 xfs_buf_submit fs/xfs/xfs_buf.c:58 [inline]
 xfs_buf_read_uncached+0x15d/0x230 fs/xfs/xfs_buf.c:885
 xfs_readsb+0x172/0x630 fs/xfs/xfs_mount.c:178
 xfs_fs_fill_super+0x583/0x13e0 fs/xfs/xfs_super.c:1516
 get_tree_bdev+0x3e6/0x610 fs/super.c:1336
 vfs_get_tree+0x88/0x270 fs/super.c:1541
 do_new_mount+0x247/0xa40 fs/namespace.c:3034
 do_mount fs/namespace.c:3377 [inline]
 __do_sys_mount fs/namespace.c:3585 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f47dc921159
RSP: 002b:00007f47dbf81028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f47dcba8fa0 RCX: 00007f47dc921159
RDX: 00002000000002c0 RSI: 0000200000000280 RDI: 0000200000000080
RBP: 00007f47dc9b8024 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000281841d R11: 0000000000000246 R12: 0000000000000000
R13: 00007f47dcba9038 R14: 00007f47dcba8fa0 R15: 00007ffeebe4f028
 </TASK>
INFO: task syz.4.21:4430 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.21        state:D stack:27600 pid: 4430 ppid:  4317 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2093
 do_wait_for_common+0x295/0x460 kernel/sched/completion.c:85
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
 xfs_buf_iowait+0xae/0x3d0 fs/xfs/xfs_buf.c:1573
 __xfs_buf_submit+0x3b5/0x7b0 fs/xfs/xfs_buf.c:1638
 xfs_buf_submit fs/xfs/xfs_buf.c:58 [inline]
 xfs_buf_read_uncached+0x15d/0x230 fs/xfs/xfs_buf.c:885
 xfs_readsb+0x172/0x630 fs/xfs/xfs_mount.c:178
 xfs_fs_fill_super+0x583/0x13e0 fs/xfs/xfs_super.c:1516
 get_tree_bdev+0x3e6/0x610 fs/super.c:1336
 vfs_get_tree+0x88/0x270 fs/super.c:1541
 do_new_mount+0x247/0xa40 fs/namespace.c:3034
 do_mount fs/namespace.c:3377 [inline]
 __do_sys_mount fs/namespace.c:3585 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fa6a963e159
RSP: 002b:00007fa6a8c9e028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fa6a98c5fa0 RCX: 00007fa6a963e159
RDX: 00002000000002c0 RSI: 0000200000000280 RDI: 0000200000000080
RBP: 00007fa6a96d5024 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000281841d R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa6a98c6038 R14: 00007fa6a98c5fa0 R15: 00007ffdbb2dfba8
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/0:0/7:
 #0: ffff88802b25e138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc90000cc7d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8d44d008 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x1530 net/ipv6/addrconf.c:4120
2 locks held by kworker/1:0/21:
 #0: ffff888016c72138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc90000db7d00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
1 lock held by khungtaskd/27:
 #0: ffffffff8c31ef60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
3 locks held by kworker/u4:1/144:
2 locks held by getty/3947:
 #0: ffff88802cb9a098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002d032e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158
3 locks held by kworker/1:3/4223:
 #0: ffff88802b25e138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc9000305fd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffffffff8d44d008 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x1530 net/ipv6/addrconf.c:4120
3 locks held by kworker/0:15/4293:
 #0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc9000314fd00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
 #2: ffff88805b307240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x283/0x3380 drivers/net/netdevsim/fib.c:1480
3 locks held by kworker/u5:6/4320:
1 lock held by syz.2.19/4360:
 #0: ffff88801b9f40e0 (&type->s_umount_key#53/1){+.+.}-{3:3}, at: alloc_super+0x200/0x970 fs/super.c:229
1 lock held by syz.1.22/4376:
 #0: ffff88807ab780e0 (&type->s_umount_key#53/1){+.+.}-{3:3}, at: alloc_super+0x200/0x970 fs/super.c:229
1 lock held by syz.0.17/4403:
 #0: ffff88802335e0e0 (&type->s_umount_key#53/1){+.+.}-{3:3}, at: alloc_super+0x200/0x970 fs/super.c:229
1 lock held by syz.3.24/4429:
 #0: ffff88807c1ba0e0 (&type->s_umount_key#53/1){+.+.}-{3:3}, at: alloc_super+0x200/0x970 fs/super.c:229
1 lock held by syz.4.21/4430:
 #0: ffff88802820c0e0 (&type->s_umount_key#53/1){+.+.}-{3:3}, at: alloc_super+0x200/0x970 fs/super.c:229
1 lock held by syz.5.33/4538:
 #0: ffff888077d660e0 (&type->s_umount_key#53/1){+.+.}-{3:3}, at: alloc_super+0x200/0x970 fs/super.c:229
1 lock held by syz.6.26/4549:
 #0: ffff888075f760e0 (&type->s_umount_key#53/1){+.+.}-{3:3}, at: alloc_super+0x200/0x970 fs/super.c:229
1 lock held by syz.7.37/4601:
 #0: ffff88805cccc0e0 (&type->s_umount_key#53/1){+.+.}-{3:3}, at: alloc_super+0x200/0x970 fs/super.c:229
1 lock held by syz.9.38/4636:
 #0: ffff88801f6cc0e0 (&type->s_umount_key#53/1){+.+.}-{3:3}, at: alloc_super+0x200/0x970 fs/super.c:229
1 lock held by syz.8.43/4685:
 #0: ffff88801fdba0e0 (&type->s_umount_key#53/1){+.+.}-{3:3}, at: alloc_super+0x200/0x970 fs/super.c:229
2 locks held by syz.2.44/4717:
 #0: ffff8880170af010 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
 #1: ffff88801b9f40e0 (&type->s_umount_key#54){+.+.}-{3:3}, at: grab_super+0x53/0x190 fs/super.c:389
1 lock held by syz.2.44/4718:
 #0: ffff888020f3a208 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
2 locks held by syz.1.45/4729:
 #0: ffff888017009210 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
 #1: ffff88807ab780e0 (&type->s_umount_key#54){+.+.}-{3:3}, at: grab_super+0x53/0x190 fs/super.c:389
1 lock held by syz.1.45/4733:
 #0: ffff888020eea208 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
2 locks held by syz.0.46/4744:
 #0: ffff8880170ae450 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
 #1: ffff88802335e0e0 (&type->s_umount_key#54){+.+.}-{3:3}, at: grab_super+0x53/0x190 fs/super.c:389
1 lock held by syz.0.46/4748:
 #0: ffff888020d7d208 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
2 locks held by syz.3.47/4762:
 #0: ffff8880170b0650 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
 #1: ffff88807c1ba0e0 (&type->s_umount_key#54){+.+.}-{3:3}, at: grab_super+0x53/0x190 fs/super.c:389
1 lock held by syz.3.47/4763:
 #0: ffff888020f48a08 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
2 locks held by syz.4.48/4775:
 #0: ffff888017009dd0 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
 #1: ffff88802820c0e0 (&type->s_umount_key#54){+.+.}-{3:3}, at: grab_super+0x53/0x190 fs/super.c:389
1 lock held by syz.4.48/4776:
 #0: ffff888020f10a08 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
2 locks held by syz.5.49/4799:
 #0: ffff8880170b1210 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
 #1: ffff888077d660e0 (&type->s_umount_key#54){+.+.}-{3:3}, at: grab_super+0x53/0x190 fs/super.c:389
1 lock held by syz.5.49/4802:
 #0: ffff888020f4f208 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
2 locks held by syz.6.50/4824:
 #0: ffff88801700a990 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
 #1: ffff888075f760e0 (&type->s_umount_key#54){+.+.}-{3:3}, at: grab_super+0x53/0x190 fs/super.c:389
1 lock held by syz.6.50/4828:
 #0: ffff888020f17208 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
2 locks held by syz.7.51/4845:
 #0: ffff8880170b1dd0 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
 #1: ffff88805cccc0e0 (&type->s_umount_key#54){+.+.}-{3:3}, at: grab_super+0x53/0x190 fs/super.c:389
1 lock held by syz.7.51/4849:
 #0: ffff888021065a08 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
2 locks held by syz.9.52/4869:
 #0: ffff8880170b2990 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
 #1: ffff88801f6cc0e0 (&type->s_umount_key#54){+.+.}-{3:3}, at: grab_super+0x53/0x190 fs/super.c:389
1 lock held by syz.9.52/4870:
 #0: ffff88802107a208 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
2 locks held by syz.8.53/4882:
 #0: ffff88801700b550 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
 #1: ffff88801fdba0e0 (&type->s_umount_key#54){+.+.}-{3:3}, at: grab_super+0x53/0x190 fs/super.c:389
1 lock held by syz.8.53/4883:
 #0: ffff8880210b5a08 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
1 lock held by syz.2.54/4901:
 #0: ffff8880170af010 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
1 lock held by syz.2.54/4902:
 #0: ffff888020f3a208 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
1 lock held by syz.1.55/4919:
 #0: ffff888017009210 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
1 lock held by syz.1.55/4922:
 #0: ffff888020eea208 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
1 lock held by syz.0.56/4930:
 #0: ffff8880170ae450 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
1 lock held by syz.0.56/4933:
 #0: ffff888020d7d208 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
1 lock held by syz.3.57/4951:
 #0: ffff8880170b0650 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
1 lock held by syz.3.57/4953:
 #0: ffff888020f48a08 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
1 lock held by syz.4.58/4967:
 #0: ffff888017009dd0 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
1 lock held by syz.4.58/4968:
 #0: ffff888020f10a08 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
1 lock held by syz.5.59/4997:
 #0: ffff8880170b1210 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
1 lock held by syz.5.59/5000:
 #0: ffff888020f4f208 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
1 lock held by syz.6.60/5020:
 #0: ffff88801700a990 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
1 lock held by syz.6.60/5022:
 #0: ffff888020f17208 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
1 lock held by syz.7.61/5039:
 #0: ffff8880170b1dd0 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
1 lock held by syz.7.61/5042:
 #0: ffff888021065a08 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
1 lock held by syz.9.62/5063:
 #0: ffff8880170b2990 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
1 lock held by syz.9.62/5064:
 #0: ffff88802107a208 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
1 lock held by syz.8.63/5077:
 #0: ffff88801700b550 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
1 lock held by syz.8.63/5080:
 #0: ffff8880210b5a08 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
1 lock held by syz.2.64/5094:
 #0: ffff8880170af010 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
1 lock held by syz.2.64/5095:
 #0: ffff888020f3a208 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
1 lock held by syz.1.65/5111:
 #0: ffff888017009210 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
1 lock held by syz.1.65/5112:
 #0: ffff888020eea208 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
1 lock held by syz.0.66/5126:
 #0: ffff8880170ae450 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
1 lock held by syz.0.66/5130:
 #0: ffff888020d7d208 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
1 lock held by syz.3.67/5140:
 #0: ffff8880170b0650 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
1 lock held by syz.3.67/5142:
 #0: ffff888020f48a08 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
1 lock held by syz.4.68/5162:
 #0: ffff888017009dd0 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
1 lock held by syz.4.68/5163:
 #0: ffff888020f10a08 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
1 lock held by syz.5.69/5186:
 #0: ffff8880170b1210 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
1 lock held by syz.5.69/5187:
 #0: ffff888020f4f208 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
1 lock held by syz.6.70/5204:
 #0: ffff88801700a990 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
1 lock held by syz.6.70/5206:
 #0: ffff888020f17208 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
1 lock held by syz.7.71/5228:
 #0: ffff8880170b1dd0 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
1 lock held by syz.7.71/5229:
 #0: ffff888021065a08 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
3 locks held by syz-executor/5241:
 #0: ffffffff8d44d008 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d44d008 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695
 #1: ffff88802dda53e8 (&wg->device_update_lock){+.+.}-{3:3}, at: wg_open+0x223/0x420 drivers/net/wireguard/device.c:49
 #2: ffffffff8c3239e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #2: ffffffff8c3239e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2d1/0x750 kernel/rcu/tree_exp.h:845
1 lock held by syz.9.72/5249:
 #0: ffff8880170b2990 (&bdev->bd_fsfreeze_mutex){+.+.}-{3:3}, at: get_tree_bdev+0x194/0x610 fs/super.c:1296
1 lock held by syz.9.72/5250:
 #0: ffff88802107a208 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x13e/0xe80 drivers/block/nbd.c:1475
1 lock held by syz-executor/5262:
 #0: ffffffff8d44d008 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d44d008 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695
1 lock held by syz-executor/5268:
 #0: ffffffff8d44d008 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d44d008 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695
2 locks held by dhcpcd/5271:
 #0: ffff888031b74120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff888031b74120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xd60 net/packet/af_packet.c:3243
 #1: ffffffff8c3239e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
 #1: ffffffff8c3239e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3a5/0x750 kernel/rcu/tree_exp.h:845
1 lock held by dhcpcd/5272:
 #0: ffff88802385a120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff88802385a120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xd60 net/packet/af_packet.c:3243
1 lock held by dhcpcd/5273:
 #0: ffff8880782b2120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline]
 #0: ffff8880782b2120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xd60 net/packet/af_packet.c:3243

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe1b/0xe60 kernel/hung_task.c:369
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4383 Comm: kworker/u4:6 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: bat_events batadv_nc_worker
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:29 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:check_preemption_disabled+0x56/0x110 lib/smp_processor_id.c:19
Code: 74 1f 65 48 8b 0c 25 28 00 00 00 48 3b 4c 24 08 0f 85 c4 00 00 00 48 83 c4 10 5b 41 5e 41 5f 5d c3 48 c7 04 24 00 00 00 00 9c <8f> 04 24 f7 04 24 00 02 00 00 74 cc 65 4c 8b 3d 16 eb 41 76 41 f6
RSP: 0018:ffffc900033cfa60 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000080000000
RDX: 0000000000000000 RSI: ffffffff8a2b39e0 RDI: ffffffff8a7a4540
RBP: ffffc900033cfbc0 R08: ffffffff8d8b122f R09: 1ffffffff1b16245
R10: dffffc0000000000 R11: fffffbfff1b16246 R12: ffffffff8c31ef60
R13: 1ffff92000679f60 R14: 0000000000000246 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc90461a2c4 CR3: 0000000040e9f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lockdep_recursion_inc kernel/locking/lockdep.c:431 [inline]
 lock_acquire+0x166/0x400 kernel/locking/lockdep.c:5622
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
 batadv_nc_worker+0xc9/0x5c0 net/batman-adv/network-coding.c:723
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/05 16:21 linux-5.15.y 0996e0926f6b 4f7b22a0 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in __xfs_buf_submit
2026/09/05 05:32 linux-5.15.y 0996e0926f6b 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in __xfs_buf_submit
2026/09/05 05:19 linux-5.15.y 0996e0926f6b 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in __xfs_buf_submit
* Struck through repros no longer work on HEAD.