INFO: task syz.6.6709:20667 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.6709 state:D stack:27192 pid:20667 tgid:20666 ppid:19250 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5260 [inline]
__schedule+0x1472/0x4fe0 kernel/sched/core.c:6867
__schedule_loop kernel/sched/core.c:6949 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7245
rt_mutex_slowlock_block+0x508/0x680 kernel/locking/rtmutex.c:1647
__rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline]
rt_mutex_slowlock+0x2dc/0x710 kernel/locking/rtmutex.c:1800
__rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:534 [inline]
mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:552
sync_bdevs+0x27e/0x470 block/bdev.c:1305
ksys_sync+0xc5/0x170 fs/sync.c:105
__ia32_sys_sync+0xe/0x20 fs/sync.c:113
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7a1ca4aeb9
RSP: 002b:00007f7a1aca6028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f7a1ccc5fa0 RCX: 00007f7a1ca4aeb9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f7a1ccc5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7a1ccc6038 R14: 00007f7a1ccc5fa0 R15: 00007ffd9e082208
Showing all locks held in the system:
1 lock held by khungtaskd/38:
#0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
6 locks held by kworker/u8:7/1210:
2 locks held by getty/5557:
#0: ffff888035a2a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211
1 lock held by udevd/8988:
#0: ffff88802525e4c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xcc0 block/bdev.c:962
1 lock held by syz.6.6709/20667:
#0: ffff88802525e4c8 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x27e/0x470 block/bdev.c:1305
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
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:161 [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:346 [inline]
watchdog+0xf90/0xfe0 kernel/hung_task.c:515
kthread+0x726/0x8b0 kernel/kthread.c:463
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 1210 Comm: kworker/u8:7 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:rcu_read_lock include/linux/rcupdate.h:865 [inline]
RIP: 0010:class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
RIP: 0010:unwind_next_frame+0x99/0x23c0 arch/x86/kernel/unwind_orc.c:495
Code: c1 ec 03 41 0f b6 04 2c 84 c0 0f 85 e7 1b 00 00 41 8b 06 85 c0 0f 84 4f 02 00 00 89 84 24 8c 00 00 00 4c 89 bc 24 90 00 00 00 22 9a 33 00 4c 8d 3d 00 00 00 00 48 c7 c7 c0 77 bc 8d 31 f6 31
RSP: 0018:ffffc90004e5eff8 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffffff88db68d6 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: ffffffff88db68d6 RDI: ffffc90004e5f0c8
RBP: dffffc0000000000 R08: ffffc90004e5f190 R09: 0000000000000008
R10: ffffc90004e5f118 R11: ffffffff81ae61c0 R12: 1ffff920009cbe19
R13: ffffc90004e5f100 R14: ffffc90004e5f0c8 R15: ffffc90004e5f900
FS: 0000000000000000(0000) GS:ffff8881266c9000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055aa679cc168 CR3: 000000000d9b4000 CR4: 00000000003526f0
Call Trace:
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
save_stack+0x124/0x230 mm/page_owner.c:165
__set_page_owner+0x8d/0x4b0 mm/page_owner.c:341
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x228/0x280 mm/page_alloc.c:1884
prep_new_page mm/page_alloc.c:1892 [inline]
get_page_from_freelist+0x28bb/0x2950 mm/page_alloc.c:3945
__alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5240
alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2486
alloc_slab_page mm/slub.c:3075 [inline]
allocate_slab+0x86/0x3a0 mm/slub.c:3248
new_slab mm/slub.c:3302 [inline]
___slab_alloc+0xaf8/0x13d0 mm/slub.c:4656
__slab_alloc+0xc5/0x1f0 mm/slub.c:4779
__slab_alloc_node mm/slub.c:4855 [inline]
slab_alloc_node mm/slub.c:5251 [inline]
__do_kmalloc_node mm/slub.c:5656 [inline]
__kmalloc_node_track_caller_noprof+0x2b6/0x7f0 mm/slub.c:5768
kmalloc_reserve+0x136/0x290 net/core/skbuff.c:608
__alloc_skb+0x204/0x390 net/core/skbuff.c:690
alloc_skb include/linux/skbuff.h:1383 [inline]
nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:818 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:875 [inline]
nsim_dev_trap_report_work+0x29f/0xbc0 drivers/net/netdevsim/dev.c:921
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340
worker_thread+0xda6/0x1360 kernel/workqueue.c:3421
kthread+0x726/0x8b0 kernel/kthread.c:463
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246