syzbot

INFO: task kworker/u8:11:2213 blocked in I/O wait for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_time[  240.901537][   T37] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:11   state:D stack:21056 pid:2213  tgid:2213  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5504 [inline]
 __schedule+0x16dc/0x5500 kernel/sched/core.c:7228
 __schedule_loop kernel/sched/core.c:7307 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7322
 io_schedule+0x80/0xe0 kernel/sched/core.c:8150
 folio_wait_bit_common+0x83c/0xbc0 mm/filemap.c:1324
 folio_lock include/linux/pagemap.h:1159 [inline]
 writeback_get_folio mm/page-writeback.c:2435 [inline]
 writeback_iter+0x957/0x1320 mm/page-writeback.c:2529
 blkdev_writepages+0xd5/0x1b0 block/fops.c:484
 do_writepages+0x338/0x560 mm/page-writeback.c:2571
 __writeback_single_inode+0x12e/0xf90 fs/fs-writeback.c:1787
 writeback_sb_inodes+0x9db/0x1ab0 fs/fs-writeback.c:2079
 __writeback_inodes_wb+0x114/0x240 fs/fs-writeback.c:2155
 wb_writeback+0x42f/0xad0 fs/fs-writeback.c:2266
 wb_check_start_all fs/fs-writeback.c:2392 [inline]
 wb_do_writeback fs/fs-writeback.c:2439 [inline]
 wb_workfn+0x986/0x10f0 fs/fs-writeback.c:2477
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
INFO: task udevd:5609 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:24576 pid:5609  tgid:5609  ppid:4962   task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5504 [inline]
 __schedule+0x16dc/0x5500 kernel/sched/core.c:7228
 __schedule_loop kernel/sched/core.c:7307 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7603
 rt_mutex_slowlock_block+0x55c/0x680 kernel/locking/rtmutex.c:1670
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
 __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline]
 rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827
 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
 __mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline]
 mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578
 bdev_release+0x1be/0x690 block/bdev.c:1131
 blkdev_release+0x15/0x20 block/fops.c:680
 __fput+0x42a/0xa80 fs/file_table.c:512
 fput_close_sync+0x11f/0x240 fs/file_table.c:617
 __do_sys_close fs/open.c:1538 [inline]
 __se_sys_close fs/open.c:1523 [inline]
 __x64_sys_close+0x7e/0x110 fs/open.c:1523
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc4b5aed407
RSP: 002b:00007ffe9d9faa90 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00007fc4b59ff880 RCX: 00007fc4b5aed407
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000008
RBP: 00007fc4b59ff6e8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000002
R13: 0000560adb12b190 R14: 0000000000000008 R15: 0000560adb15a260
 </TASK>
INFO: task syz.2.666:6562 blocked in I/O wait for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.666       state:D stack:25112 pid:6562  tgid:6562  ppid:5746   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5504 [inline]
 __schedule+0x16dc/0x5500 kernel/sched/core.c:7228
 __schedule_loop kernel/sched/core.c:7307 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7322
 io_schedule+0x80/0xe0 kernel/sched/core.c:8150
 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:250
 __wait_on_bit_lock+0xe0/0x4a0 kernel/sched/wait_bit.c:93
 out_of_line_wait_on_bit_lock+0x13b/0x190 kernel/sched/wait_bit.c:120
 wait_on_bit_lock_io include/linux/wait_bit.h:221 [inline]
 __lock_buffer fs/buffer.c:68 [inline]
 lock_buffer include/linux/buffer_head.h:434 [inline]
 __block_write_full_folio+0x55c/0xdd0 fs/buffer.c:1888
 blkdev_writepages+0xef/0x1b0 block/fops.c:485
 do_writepages+0x338/0x560 mm/page-writeback.c:2571
 filemap_writeback mm/filemap.c:388 [inline]
 filemap_fdatawrite_range mm/filemap.c:413 [inline]
 filemap_fdatawrite+0x1ec/0x2f0 mm/filemap.c:419
 sync_bdevs+0x304/0x470 block/bdev.c:1309
 ksys_sync fs/sync.c:105 [inline]
 __ia32_sys_sync+0xc5/0x120 fs/sync.c:111
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7febfe0ece59
RSP: 002b:00007ffc18c791c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007febfe365fa0 RCX: 00007febfe0ece59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000001d3e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007febfe365fac R14: 00007febfe365fa0 R15: 00007febfe365fa0
 </TASK>
INFO: task syz.4.664:6563 blocked in I/O wait for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.664       state:D stack:25752 pid:6563  tgid:6563  ppid:5743   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5504 [inline]
 __schedule+0x16dc/0x5500 kernel/sched/core.c:7228
 __schedule_loop kernel/sched/core.c:7307 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7322
 io_schedule+0x80/0xe0 kernel/sched/core.c:8150
 folio_wait_bit_common+0x83c/0xbc0 mm/filemap.c:1324
 folio_lock include/linux/pagemap.h:1159 [inline]
 __find_get_block_slow fs/buffer.c:242 [inline]
 find_get_block_common+0x34f/0xe10 fs/buffer.c:1386
 bdev_getblk+0x58/0x6e0 include/linux/gfp.h:-1
 __bread_gfp+0x89/0x380 fs/buffer.c:1493
 sb_bread include/linux/buffer_head.h:348 [inline]
 hfs_mdb_commit+0xac7/0x1160 fs/hfs/mdb.c:344
 hfs_sync_fs+0x1d/0x30 fs/hfs/super.c:38
 __iterate_supers+0x137/0x240 fs/super.c:867
 ksys_sync fs/sync.c:103 [inline]
 __ia32_sys_sync+0xaf/0x120 fs/sync.c:111
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2b98b5ce59
RSP: 002b:00007ffe835da2d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f2b98dd5fa0 RCX: 00007f2b98b5ce59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000001d3e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2b98dd5fac R14: 00007f2b98dd5fa0 R15: 00007f2b98dd5fa0
 </TASK>
INFO: task syz.0.662:6564 blocked in I/O wait for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.662       state:D stack:26008 pid:6564  tgid:6564  ppid:5734   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5504 [inline]
 __schedule+0x16dc/0x5500 kernel/sched/core.c:7228
 __schedule_loop kernel/sched/core.c:7307 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7322
 io_schedule+0x80/0xe0 kernel/sched/core.c:8150
 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:250
 __wait_on_bit_lock+0xe0/0x4a0 kernel/sched/wait_bit.c:93
 out_of_line_wait_on_bit_lock+0x13b/0x190 kernel/sched/wait_bit.c:120
 lock_buffer include/linux/buffer_head.h:434 [inline]
 hfs_mdb_commit+0x115/0x1160 fs/hfs/mdb.c:294
 hfs_sync_fs+0x1d/0x30 fs/hfs/super.c:38
 __iterate_supers+0x137/0x240 fs/super.c:867
 ksys_sync fs/sync.c:103 [inline]
 __ia32_sys_sync+0xaf/0x120 fs/sync.c:111
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7d5b73ce59
RSP: 002b:00007ffed974d598 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f7d5b9b5fa0 RCX: 00007f7d5b73ce59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000001d3e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7d5b9b5fac R14: 00007f7d5b9b5fa0 R15: 00007f7d5b9b5fa0
 </TASK>
INFO: task syz.3.663:6565 blocked in I/O wait for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.663       state:D stack:26008 pid:6565  tgid:6565  ppid:5750   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5504 [inline]
 __schedule+0x16dc/0x5500 kernel/sched/core.c:7228
 __schedule_loop kernel/sched/core.c:7307 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7322
 io_schedule+0x80/0xe0 kernel/sched/core.c:8150
 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:250
 __wait_on_bit_lock+0xe0/0x4a0 kernel/sched/wait_bit.c:93
 out_of_line_wait_on_bit_lock+0x13b/0x190 kernel/sched/wait_bit.c:120
 lock_buffer include/linux/buffer_head.h:434 [inline]
 hfs_mdb_commit+0x115/0x1160 fs/hfs/mdb.c:294
 hfs_sync_fs+0x1d/0x30 fs/hfs/super.c:38
 __iterate_supers+0x137/0x240 fs/super.c:867
 ksys_sync fs/sync.c:103 [inline]
 __ia32_sys_sync+0xaf/0x120 fs/sync.c:111
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2af60cce59
RSP: 002b:00007ffe584c4c38 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f2af6345fa0 RCX: 00007f2af60cce59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000001d3e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2af6345fac R14: 00007f2af6345fa0 R15: 00007f2af6345fa0
 </TASK>
INFO: task syz.1.665:6566 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.665       state:D stack:26008 pid:6566  tgid:6566  ppid:5737   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5504 [inline]
 __schedule+0x16dc/0x5500 kernel/sched/core.c:7228
 __schedule_loop kernel/sched/core.c:7307 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7322
 wb_wait_for_completion+0x3b2/0x700 fs/fs-writeback.c:227
 sync_inodes_sb+0x226/0xc30 fs/fs-writeback.c:3030
 __iterate_supers+0x137/0x240 fs/super.c:867
 ksys_sync fs/sync.c:102 [inline]
 __ia32_sys_sync+0xa0/0x120 fs/sync.c:111
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6e5df6ce59
RSP: 002b:00007fff2d5b6f38 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f6e5e1e5fa0 RCX: 00007f6e5df6ce59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000001d3e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6e5e1e5fac R14: 00007f6e5e1e5fa0 R15: 00007f6e5e1e5fa0
 </TASK>
INFO: lockdep is turned off.
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
 watchdog+0xfd7/0x1030 kernel/hung_task.c:561
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 17 Comm: pr/legacy Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:rdtsc_ordered arch/x86/include/asm/tsc.h:57 [inline]
RIP: 0010:delay_tsc+0x71/0xc0 arch/x86/lib/delay.c:72
Code: 00 00 e8 c2 89 73 f6 65 8b 05 bb e7 4d 07 85 c0 74 1c f3 90 bf 01 00 00 00 e8 0b 88 73 f6 e8 96 79 01 00 39 c5 75 0e 0f 01 f9 <66> 90 eb bd e8 a6 36 13 f6 eb dd 4c 29 fb e8 7c 79 01 00 89 c5 0f
RSP: 0018:ffffc90000167a08 EFLAGS: 00000246
RAX: 000000009f2eeb96 RBX: 0000000000000899 RCX: 0000000000000000
RDX: 000000000000007f RSI: ffffffff8ba7f080 RDI: ffffffff8ba7f040
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff8b1fd820 R12: 1ffffffff3368f92
R13: 00000000ffffffff R14: 0000007f9f2ee7aa R15: 000000000000035c
FS:  0000000000000000(0000) GS:ffff888126144000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f33ef80fe9c CR3: 000000000ddb0000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 udelay include/asm-generic/delay.h:62 [inline]
 wait_for_lsr+0x14d/0x300 drivers/tty/serial/8250/8250_port.c:1979
 serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3210 [inline]
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3275 [inline]
 serial8250_console_write+0x1232/0x1bd0 drivers/tty/serial/8250/8250_port.c:3360
 console_emit_next_record kernel/printk/printk.c:3163 [inline]
 console_flush_one_record+0x642/0xb50 kernel/printk/printk.c:3269
 legacy_kthread_func+0x1b6/0x250 kernel/printk/printk.c:3712
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>