INFO: task kworker/u8:0:12 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:0 state:D stack:21280 pid:12 tgid:12 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:7)
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0x1553/0x5240 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7289
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/0x7b0 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
jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108
jfs_write_inode+0x145/0x220 fs/jfs/inode.c:138
write_inode fs/fs-writeback.c:1582 [inline]
__writeback_single_inode+0x75d/0x11a0 fs/fs-writeback.c:1825
writeback_sb_inodes+0x995/0x19d0 fs/fs-writeback.c:2054
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2130
wb_writeback+0x46a/0xb70 fs/fs-writeback.c:2241
wb_check_old_data_flush fs/fs-writeback.c:2345 [inline]
wb_do_writeback fs/fs-writeback.c:2398 [inline]
wb_workfn+0xb52/0xf60 fs/fs-writeback.c:2426
process_one_work kernel/workqueue.c:3276 [inline]
process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 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:
4 locks held by kworker/u8:0/12:
#0: ffff88801f2d7938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
#0: ffff88801f2d7938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
#1: ffffc90000117c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
#1: ffffc90000117c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
#2: ffff88803423a0d0 (&type->s_umount_key#63){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:565
#3: ffff88804053b2a8 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108
1 lock held by khungtaskd/38:
#0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
6 locks held by kworker/u8:2/43:
4 locks held by kworker/u8:3/57:
2 locks held by kworker/u8:10/1183:
2 locks held by getty/5554:
#0: ffff8880374de0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e7e2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211
4 locks held by syz.7.834/12014:
10 locks held by syz-executor/12194:
1 lock held by udevd/12277:
#0: ffff888032b47a58 (&group->inotify_data.idr_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#0: ffff888032b47a58 (&group->inotify_data.idr_lock){+.+.}-{3:3}, at: inotify_idr_find fs/notify/inotify/inotify_user.c:441 [inline]
#0: ffff888032b47a58 (&group->inotify_data.idr_lock){+.+.}-{3:3}, at: __do_sys_inotify_rm_watch fs/notify/inotify/inotify_user.c:801 [inline]
#0: ffff888032b47a58 (&group->inotify_data.idr_lock){+.+.}-{3:3}, at: __se_sys_inotify_rm_watch+0x9c/0x1f0 fs/notify/inotify/inotify_user.c:786
1 lock held by udevd/12354:
#0: ffff888032b479a0 (&group->mark_mutex){+.+.}-{4:4}, at: fsnotify_group_lock include/linux/fsnotify_backend.h:289 [inline]
#0: ffff888032b479a0 (&group->mark_mutex){+.+.}-{4:4}, at: inotify_update_watch fs/notify/inotify/inotify_user.c:642 [inline]
#0: ffff888032b479a0 (&group->mark_mutex){+.+.}-{4:4}, at: __do_sys_inotify_add_watch fs/notify/inotify/inotify_user.c:781 [inline]
#0: ffff888032b479a0 (&group->mark_mutex){+.+.}-{4:4}, at: __se_sys_inotify_add_watch+0x36a/0xf70 fs/notify/inotify/inotify_user.c:729
3 locks held by kworker/0:9/12632:
2 locks held by udevd/12690:
5 locks held by udevd/12877:
1 lock held by udevd/12883:
2 locks held by syz.9.1040/13778:
#0: ffff888025a3e498 (&lo->lo_mutex){+.+.}-{4:4}, at: loop_global_lock_killable drivers/block/loop.c:118 [inline]
#0: ffff888025a3e498 (&lo->lo_mutex){+.+.}-{4:4}, at: loop_configure+0x37b/0xdf0 drivers/block/loop.c:1016
#1: ffff8880b893a0b8 ((lock)){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#1: ffff8880b893a0b8 ((lock)){+.+.}-{3:3}, at: __radix_tree_preload+0x141/0x870 lib/radix-tree.c:334
2 locks held by rm/13792:
2 locks held by syz.4.1044/13793:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
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+0xfd9/0x1030 kernel/hung_task.c:515
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 43 Comm: kworker/u8:2 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:kasan_check_range+0x1c8/0x2c0 mm/kasan/generic.c:200
Code: 49 01 dc 4d 01 f3 49 8d 5c 24 07 4d 85 e4 49 0f 49 dc 48 83 e3 f8 49 29 dc 74 0e 41 80 3b 00 75 7c 49 ff c3 49 ff cc 75 f2 5b <41> 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 45 84 ff 0f 85 a1 00
RSP: 0018:ffffc90000b57468 EFLAGS: 00000256
RAX: ffffc90000b57901 RBX: 0000000000000010 RCX: ffffffff81768c6e
RDX: 0000000000000001 RSI: 0000000000000010 RDI: ffffc90000b575d8
RBP: 0000000000000000 R08: ffffc90000b575e7 R09: 1ffff9200016aebc
R10: dffffc0000000000 R11: fffff5200016aebd R12: 0000000000000002
R13: 1ffff9200016aeb3 R14: fffff5200016aebd R15: 1ffff9200016aebb
FS: 0000000000000000(0000) GS:ffff888126436000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd15993c000 CR3: 000000005cf78000 CR4: 00000000003526f0
Call Trace:
__asan_memset+0x22/0x50 mm/kasan/shadow.c:84
unwind_next_frame+0xeae/0x23c0 arch/x86/kernel/unwind_orc.c:607
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__do_kmalloc_node mm/slub.c:5260 [inline]
__kmalloc_node_track_caller_noprof+0x372/0x7e0 mm/slub.c:5368
kmalloc_reserve net/core/skbuff.c:635 [inline]
__alloc_skb+0x2c1/0x7d0 net/core/skbuff.c:713
alloc_skb include/linux/skbuff.h:1383 [inline]
nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:819 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline]
nsim_dev_trap_report_work+0x29f/0xbc0 drivers/net/netdevsim/dev.c:922
process_one_work kernel/workqueue.c:3276 [inline]
process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245