INFO: task syz.3.1804:16355 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.1804 state:D stack:27016 pid:16355 ppid:15501 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6833
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6a9/0xcc0 kernel/locking/mutex.c:747
blkdev_put+0xff/0x760 block/bdev.c:944
blkdev_release+0x84/0x90 block/fops.c:604
__fput+0x234/0x970 fs/file_table.c:384
task_work_run+0x1d4/0x260 kernel/task_work.c:245
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+0xee/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+0x61/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f48ab59c799
RSP: 002b:00007fff01910098 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f48ab817da0 RCX: 00007f48ab59c799
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f48ab817da0 R08: 0000000000000006 R09: 0000000000000000
R10: 00007f48ab817cb0 R11: 0000000000000246 R12: 00000000001c6927
R13: 00007f48ab815fac R14: 00000000001c6652 R15: 00007fff019101a0
INFO: task syz.3.1804:16357 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.1804 state:D stack:27880 pid:16357 ppid:15501 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6833
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6a9/0xcc0 kernel/locking/mutex.c:747
blkdev_put+0xff/0x760 block/bdev.c:944
blkdev_release+0x84/0x90 block/fops.c:604
__fput+0x234/0x970 fs/file_table.c:384
task_work_run+0x1d4/0x260 kernel/task_work.c:245
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+0xee/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+0x61/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f48ab59c799
RSP: 002b:00007f48ac489028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007f48ab815fa0 RCX: 00007f48ab59c799
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000004
RBP: 00007f48ab632bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f48ab816038 R14: 00007f48ab815fa0 R15: 00007fff0190ff38
Showing all locks held in the system:
1 lock held by khungtaskd/29:
#0: ffffffff8d131fa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
#0: ffffffff8d131fa0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
#0: ffffffff8d131fa0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
4 locks held by dhcpcd/5434:
2 locks held by getty/5530:
#0: ffff88814cd2f0a0 (&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+0x433/0x1390 drivers/tty/n_tty.c:2217
1 lock held by udevd/15505:
#0: ffff888021cab4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:805
1 lock held by syz.3.1804/16355:
#0: ffff888021cab4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xff/0x760 block/bdev.c:944
1 lock held by syz.3.1804/16357:
#0: ffff888021cab4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xff/0x760 block/bdev.c:944
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
nmi_cpu_backtrace+0x3a6/0x3e0 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+0xf3d/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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5433 Comm: dhcpcd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:in_gate_area_no_mm+0x14/0x50 arch/x86/entry/vsyscall/vsyscall_64.c:332
Code: c6 44 89 f0 5b 41 5e 41 5f 5d c3 66 2e 0f 1f 84 00 00 00 00 00 90 66 0f 1f 00 55 53 48 89 fb e8 f2 78 86 00 8b 2d dc 73 a6 0b 02 00 00 00 89 ee e8 90 7c 86 00 83 fd 02 40 0f 95 c5 48 81 e3
RSP: 0018:ffffc900037b7098 EFLAGS: 00000293
RAX: ffffffff81009c1e RBX: 00007fd54191f407 RCX: ffff888026d9bc00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00007fd54191f407
RBP: 0000000000000001 R08: ffff888026d9bc00 R09: 0000000000000003
R10: 0000000000000004 R11: 0000000000000000 R12: ffffffff8aa000d0
R13: ffffc900037b7528 R14: dffffc0000000000 R15: 1ffff920006f6e2a
FS: 00007fd541895740(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000560c203b5000 CR3: 0000000077e3c000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 00000000ffffdb67 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
is_kernel_text include/linux/kallsyms.h:31 [inline]
core_kernel_text kernel/extable.c:68 [inline]
kernel_text_address+0x2d/0xd0 kernel/extable.c:99
__kernel_text_address+0xd/0x30 kernel/extable.c:79
unwind_get_return_address+0x5d/0xc0 arch/x86/kernel/unwind_orc.c:369
arch_stack_walk+0x11d/0x190 arch/x86/kernel/stacktrace.c:26
stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237
kasan_slab_free include/linux/kasan.h:164 [inline]
slab_free_hook mm/slub.c:1811 [inline]
slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837
slab_free mm/slub.c:3830 [inline]
__kmem_cache_free+0xba/0x1e0 mm/slub.c:3843
memcg_free_slab_cgroups mm/slab.h:463 [inline]
unaccount_slab mm/slab.h:651 [inline]
__free_slab+0xbe/0x260 mm/slub.c:2097
__slab_free+0x35a/0x400 mm/slub.c:3736
qlink_free mm/kasan/quarantine.c:166 [inline]
qlist_free_all+0x75/0xd0 mm/kasan/quarantine.c:185
kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:306
kasan_slab_alloc include/linux/kasan.h:188 [inline]
slab_post_alloc_hook+0x6e/0x4b0 mm/slab.h:767
slab_alloc_node mm/slub.c:3495 [inline]
kmem_cache_alloc_node+0x14c/0x320 mm/slub.c:3540
__alloc_skb+0x103/0x2c0 net/core/skbuff.c:643
alloc_skb include/linux/skbuff.h:1284 [inline]
alloc_skb_with_frags+0xca/0x7b0 net/core/skbuff.c:6334
sock_alloc_send_pskb+0x883/0x9a0 net/core/sock.c:2821
unix_dgram_sendmsg+0x5a2/0x16d0 net/unix/af_unix.c:2001
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
sock_write_iter+0x2df/0x420 net/socket.c:1160
call_write_iter include/linux/fs.h:2018 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x46c/0x990 fs/read_write.c:584
ksys_write+0x150/0x260 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd54191f407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffe3f6b0eb0 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fd541895740 RCX: 00007fd54191f407
RDX: 000000000000003b RSI: 00007ffe3f6b0f10 RDI: 0000000000000005
RBP: 0000560c1af4e168 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffe3f6b1340
R13: 0000560c20518190 R14: 0000560c205115a0 R15: 0000560c2067b0e0
vkms_vblank_simulate: vblank timer overrun