INFO: task syz-executor:6041 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:21736 pid:6041 ppid:1 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
schedule+0xbd/0x170 kernel/sched/core.c:6773
wb_wait_for_completion+0x166/0x290 fs/fs-writeback.c:192
sync_inodes_sb+0x1bc/0x9e0 fs/fs-writeback.c:2772
sync_filesystem+0x171/0x220 fs/sync.c:64
generic_shutdown_super+0x6f/0x2b0 fs/super.c:666
kill_block_super+0x44/0x90 fs/super.c:1660
deactivate_locked_super+0x97/0x100 fs/super.c:481
cleanup_mnt+0x429/0x4c0 fs/namespace.c:1259
task_work_run+0x1ce/0x250 kernel/task_work.c:239
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f5364590a77
RSP: 002b:00007ffecb12a588 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000064 RCX: 00007f5364590a77
RDX: 0000000000000200 RSI: 0000000000000009 RDI: 00007ffecb12b730
RBP: 00007f5364613d7d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000202 R12: 00007ffecb12b730
R13: 00007f5364613d7d R14: 000055558d28a4a8 R15: 00007ffecb12c800
Showing all locks held in the system:
1 lock held by khungtaskd/29:
#0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
#0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
#0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
2 locks held by kworker/u4:8/3457:
2 locks held by kworker/u4:9/3470:
#0: ffff888140050138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#0: ffff888140050138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
#1: ffffc9000d267d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
#1: ffffc9000d267d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
2 locks held by getty/5529:
#0: ffff88814cbe60a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000326e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x425/0x1380 drivers/tty/n_tty.c:2217
2 locks held by syz-executor/6041:
#0: ffff88805dd9a0e0 (&type->s_umount_key#82){+.+.}-{3:3}, at: __super_lock fs/super.c:56 [inline]
#0: ffff88805dd9a0e0 (&type->s_umount_key#82){+.+.}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
#0: ffff88805dd9a0e0 (&type->s_umount_key#82){+.+.}-{3:3}, at: deactivate_super+0xa4/0xe0 fs/super.c:513
#1: ffff8880214127d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:364 [inline]
#1: ffff8880214127d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x1a0/0x9e0 fs/fs-writeback.c:2770
1 lock held by segctord/7293:
1 lock held by syz.8.737/9552:
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
nmi_cpu_backtrace+0x39b/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
watchdog+0xf41/0xf80 kernel/hung_task.c:379
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3470 Comm: kworker/u4:9 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: writeback wb_workfn (flush-7:4)
RIP: 0010:arch_test_and_set_bit arch/x86/include/asm/bitops.h:138 [inline]
RIP: 0010:arch_test_and_set_bit_lock arch/x86/include/asm/bitops.h:144 [inline]
RIP: 0010:test_and_set_bit_lock include/asm-generic/bitops/instrumented-lock.h:58 [inline]
RIP: 0010:folio_trylock include/linux/pagemap.h:1037 [inline]
RIP: 0010:folio_lock include/linux/pagemap.h:1073 [inline]
RIP: 0010:write_cache_pages+0x41d/0x11f0 mm/page-writeback.c:2463
Code: ff 49 83 e6 01 0f 85 51 0d 00 00 0f 1f 44 00 00 e8 c8 4b cf ff 4c 89 ff be 08 00 00 00 e8 8b bb 26 00 31 f6 f0 49 0f ba 2f 00 <41> 0f 92 c6 40 0f 92 c6 bf 02 00 00 00 e8 31 4e cf ff 45 84 f6 74
RSP: 0018:ffffc9000d267180 EFLAGS: 00000246
RAX: ffffffff81b64401 RBX: ffffea0001d7c708 RCX: ffffffff81b64505
RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffffea0001d7c700
RBP: ffffc9000d267370 R08: ffffea0001d7c707 R09: 1ffffd40003af8e0
R10: dffffc0000000000 R11: fffff940003af8e1 R12: dffffc0000000000
R13: 0000000000000002 R14: 0000000000000000 R15: ffffea0001d7c700
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005593db605168 CR3: 000000005e95b000 CR4: 00000000003506e0
Call Trace:
do_writepages+0x40e/0x600 mm/page-writeback.c:2580
__writeback_single_inode+0x153/0xee0 fs/fs-writeback.c:1635
writeback_sb_inodes+0x77c/0xef0 fs/fs-writeback.c:1926
wb_writeback+0x450/0xba0 fs/fs-writeback.c:2105
wb_do_writeback fs/fs-writeback.c:2252 [inline]
wb_workfn+0x3ff/0xe20 fs/fs-writeback.c:2292
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293