INFO: task kworker/0:1H:2018 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:1H state:D stack:25928 pid:2018 tgid:2018 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: kblockd blk_mq_run_work_fn
Call Trace:
context_switch kernel/sched/core.c:5533 [inline]
__schedule+0x17db/0x58f0 kernel/sched/core.c:7284
__schedule_loop kernel/sched/core.c:7361 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7376
schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99
wait_for_reconnect drivers/block/nbd.c:1107 [inline]
nbd_handle_cmd drivers/block/nbd.c:1149 [inline]
nbd_queue_rq+0x96f/0xff0 drivers/block/nbd.c:1207
blk_mq_dispatch_rq_list+0x499/0x1990 block/blk-mq.c:2117
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
__blk_mq_sched_dispatch_requests+0xd36/0x1580 block/blk-mq-sched.c:307
blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329
blk_mq_run_work_fn+0x16c/0x300 block/blk-mq.c:2532
process_one_work kernel/workqueue.c:3396 [inline]
process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
kthread+0x38b/0x480 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
Showing all locks held in the system:
locks held by khungtaskd/32: 1, last CPU#1:
#0: ffffffff8ed5c920 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8ed5c920 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8ed5c920 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by kworker/0:1H/2018: 4, on CPU#0:
#0: ffff888021280540 ((wq_completion)kblockd){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff888021280540 ((wq_completion)kblockd){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff888021280540 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffff888021280540 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#1: ffffc900063efc40 ((work_completion)(&(&hctx->run_work)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc900063efc40 ((work_completion)(&(&hctx->run_work)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc900063efc40 ((work_completion)(&(&hctx->run_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#1: ffffc900063efc40 ((work_completion)(&(&hctx->run_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#2: ffff888026f1a098 (set->srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:198 [inline]
#2: ffff888026f1a098 (set->srcu){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:305 [inline]
#2: ffff888026f1a098 (set->srcu){.+.+}-{0:0}, at: blk_mq_run_work_fn+0x144/0x300 block/blk-mq.c:2531
#3: ffff888027475578 (&cmd->lock){+.+.}-{4:4}, at: nbd_queue_rq+0xc1/0xff0 drivers/block/nbd.c:1199
locks held by getty/5372: 2, on CPU#0:
#0: ffff888035fae0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by udevd/5636: 1, on CPU#0:
#0: ffff8880264cb350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70 block/bdev.c:990
locks held by kworker/0:6/5725: 3, on CPU#0:
#0: ffff88801b06b140 ((wq_completion)events){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88801b06b140 ((wq_completion)events){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88801b06b140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffff88801b06b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#1: ffffc90004917c40 ((fqdir_free_work).work){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90004917c40 ((fqdir_free_work).work){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90004917c40 ((fqdir_free_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#1: ffffc90004917c40 ((fqdir_free_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#2: ffffffff8ed62bb8 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3904
locks held by kworker/u8:37/11880: 4, on CPU#1:
#0: ffff88801c2d6140 ((wq_completion)netns){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88801c2d6140 ((wq_completion)netns){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88801c2d6140 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffff88801c2d6140 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#1: ffffc9000631fc40 (net_cleanup_work){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc9000631fc40 (net_cleanup_work){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc9000631fc40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#1: ffffc9000631fc40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#2: ffffffff902466c8 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf5/0x810 net/core/net_namespace.c:677
#3: ffffffff8ed62bb8 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3904
locks held by kworker/0:2H/12865: 2, on CPU#0:
#0: ffff888021280540 ((wq_completion)kblockd){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff888021280540 ((wq_completion)kblockd){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff888021280540 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffff888021280540 ((wq_completion)kblockd){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#1: ffffc90003887c40 ((work_completion)(&q->timeout_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90003887c40 ((work_completion)(&q->timeout_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90003887c40 ((work_completion)(&q->timeout_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#1: ffffc90003887c40 ((work_completion)(&q->timeout_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
locks held by syz.0.2628/17127: 2, last CPU#0:
#0: ffff88802ab9a9f8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:600 [inline]
#0: ffff88802ab9a9f8 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x1a4/0x9f0 mm/mmap.c:1299
#1: ffffffff8ed5c920 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff8ed5c920 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff8ed5c920 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:290
locks held by syz.2.2632/17151: 3, last CPU#1:
#0: ffff88801c3a5c60 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline]
#0: ffff88801c3a5c60 (sk_lock-AF_INET){+.+.}-{0:0}, at: raw_sendmsg+0x13bd/0x1a20 net/ipv4/raw.c:658
#1: ffffffff8ed5c920 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff8ed5c920 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff8ed5c920 (rcu_read_lock){....}-{1:3}, at: ip_output+0x5a/0x450 net/ipv4/ip_output.c:432
#2: ffffffff8ed5c920 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#2: ffffffff8ed5c920 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#2: ffffffff8ed5c920 (rcu_read_lock){....}-{1:3}, at: ip_finish_output2+0x3de/0x10b0 net/ipv4/ip_output.c:229
locks held by syz.2.2632/17155: 3, last CPU#0:
#0: ffffffff907c46a8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff907c46a8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff907c46a8 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:595
#1: ffffffff90254f20 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#1: ffffffff90254f20 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:366 [inline]
#1: ffffffff90254f20 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xc1d/0x1c30 net/core/rtnetlink.c:4241
#2: ffffffff8ed5c920 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#2: ffffffff8ed5c920 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#2: ffffffff8ed5c920 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
#2: ffffffff8ed5c920 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495
locks held by syz.4.2633/17154: 1, last CPU#0:
#0: ffff88807fed7678 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:544 [inline]
#0: ffff88807fed7678 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x2d8/0x9f0 mm/mmap.c:1323
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 32 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66
trigger_all_cpu_backtrace include/linux/nmi.h:164 [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+0x38b/0x480 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
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 17154 Comm: syz.4.2633 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:98 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:115 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:140 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:172 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:191 [inline]
RIP: 0010:kasan_check_range+0x93/0x2c0 mm/kasan/generic.c:200
Code: 01 00 00 00 00 fc ff df 4d 8d 34 19 4d 89 f4 4d 29 dc 49 83 fc 10 7f 29 4d 85 e4 0f 84 3d 01 00 00 4c 89 cb 48 f7 d3 4c 01 fb <41> 80 3b 00 0f 85 9e 01 00 00 49 ff c3 48 ff c3 75 ee e9 1d 01 00
RSP: 0018:ffffc90004f3f288 EFLAGS: 00000282
RAX: f3f3f3f3f3f3f301 RBX: fffffffffffffffe RCX: ffffffff8240e9a2
RDX: 0000000000000001 RSI: 0000000000000028 RDI: ffffc90004f3f320
RBP: 0000000000000000 R08: ffffc90004f3f347 R09: 1ffff920009e7e68
R10: dffffc0000000000 R11: fffff520009e7e67 R12: 0000000000000005
R13: dffffc0000000000 R14: fffff520009e7e69 R15: 1ffff920009e7e64
FS: 0000000000000000(0000) GS:ffff888124cc6000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f44effeb840 CR3: 000000005b5ee000 CR4: 00000000003526f0
Call Trace:
__asan_memset+0x22/0x50 mm/kasan/shadow.c:84
__mem_cgroup_uncharge_folios+0xa2/0x1d0 mm/memcontrol.c:5396
mem_cgroup_uncharge_folios include/linux/memcontrol.h:690 [inline]
folios_put_refs+0x9e1/0xb30 mm/folio.c:1035
free_pages_and_swap_cache+0x2ba/0x490 mm/swap_state.c:592
__tlb_batch_free_encoded_pages mm/mmu_gather.c:138 [inline]
tlb_batch_pages_flush mm/mmu_gather.c:151 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:417 [inline]
tlb_flush_mmu+0x6d3/0xa30 mm/mmu_gather.c:424
tlb_finish_mmu+0xf4/0x220 mm/mmu_gather.c:549
exit_mmap+0x4b2/0x9f0 mm/mmap.c:1328
__mmput+0x118/0x420 kernel/fork.c:1193
exit_mm+0x221/0x2d0 kernel/exit.c:618
do_exit+0x6cd/0x2360 kernel/exit.c:1000
do_group_exit+0x22d/0x2f0 kernel/exit.c:1155
get_signal+0x121b/0x12c0 kernel/signal.c:3112
arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop+0x10e/0x770 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline]
do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f508b79e159
Code: Unable to access opcode bytes at 0x7f508b79e12f.
RSP: 002b:00007f508c5cf0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f508ba26098 RCX: 00007f508b79e159
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f508ba26098
RBP: 00007f508ba26090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f508ba26128 R14: 00007ffcf2456810 R15: 00007ffcf24568f8