INFO: task kworker/u4:10:4432 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:10 state:D stack:21184 pid:4432 ppid:2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
jfs_commit_inode+0x1c7/0x520 fs/jfs/inode.c:102
jfs_write_inode+0x141/0x220 fs/jfs/inode.c:132
write_inode fs/fs-writeback.c:1460 [inline]
__writeback_single_inode+0x75b/0x1160 fs/fs-writeback.c:1677
writeback_sb_inodes+0xad8/0x17d0 fs/fs-writeback.c:1903
__writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:1974
wb_writeback+0x47a/0xd00 fs/fs-writeback.c:2079
wb_check_background_flush fs/fs-writeback.c:2145 [inline]
wb_do_writeback fs/fs-writeback.c:2233 [inline]
wb_workfn+0xbdd/0xec0 fs/fs-writeback.c:2260
process_one_work+0x898/0x1160 kernel/workqueue.c:2292
worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
INFO: task syz.0.193:5125 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.193 state:D
stack:26728 pid:5125 ppid:4264 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
io_schedule+0x7c/0xd0 kernel/sched/core.c:8797
folio_wait_bit_common+0x6e1/0xf60 mm/filemap.c:1324
release_metapage+0x93/0x980 fs/jfs/jfs_metapage.c:735
discard_metapage fs/jfs/jfs_metapage.h:88 [inline]
__get_metapage+0xa65/0xfa0 fs/jfs/jfs_metapage.c:644
dtSplitPage+0x77f/0x31d0 fs/jfs/jfs_dtree.c:1471
dtSplitUp fs/jfs/jfs_dtree.c:1092 [inline]
dtInsert+0xfbd/0x58a0 fs/jfs/jfs_dtree.c:871
jfs_mkdir+0x6e5/0xa70 fs/jfs/namei.c:270
vfs_mkdir+0x387/0x570 fs/namei.c:4106
do_mkdirat+0x1d0/0x430 fs/namei.c:4131
__do_sys_mkdirat fs/namei.c:4146 [inline]
__se_sys_mkdirat fs/namei.c:4144 [inline]
__x64_sys_mkdirat+0x85/0x90 fs/namei.c:4144
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa48578eec9
RSP: 002b:00007fa486653038 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007fa4859e6270 RCX: 00007fa48578eec9
RDX: 00000000000001c2 RSI: 0000200000000080 RDI: ffffffffffffff9c
RBP: 00007fa485811f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa4859e6308 R14: 00007fa4859e6270 R15: 00007ffe7af2b2a8
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2b570 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cb2bd90 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/27:
#0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
1 lock held by dhcpcd/3932:
#0: ffffffff8dd42428 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
#0: ffffffff8dd42428 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x740/0xed0 net/core/rtnetlink.c:6150
2 locks held by getty/4024:
#0: ffff88802f803098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198
3 locks held by kworker/1:7/4345:
#0: ffff88802e9cb138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc900041c7d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#2: ffffffff8dd42428 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x14d0 net/ipv6/addrconf.c:4131
4 locks held by kworker/u4:10/4432:
#0: ffff888140a2b938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc900046c7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#2: ffff8880580340e0 (&type->s_umount_key#60){++++}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:415
#3: ffff888070024bc8 (&jfs_ip->commit_mutex){+.+.}-{3:3}, at: jfs_commit_inode+0x1c7/0x520 fs/jfs/inode.c:102
4 locks held by kworker/u4:12/4434:
#0: ffff8880b8e3aad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xa5/0x140 kernel/sched/core.c:545
#1: ffff8880b8e27848 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x398/0x6d0 kernel/sched/psi.c:999
#2: ffffffff8c9c7a70 (cpu_hotplug_lock){++++}-{0:0}, at: static_key_enable+0xe/0x20 kernel/jump_label.c:219
#3: ffffffff8cbc6c88 (jump_label_mutex){+.+.}-{3:3}, at: debug_object_activate+0x6a/0x490 lib/debugobjects.c:698
4 locks held by kworker/u4:17/4502:
#0: ffff888017616938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc900032e7d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#2: ffffffff8dd35750 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x132/0xb80 net/core/net_namespace.c:594
#3: ffffffff8cb30780 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x48/0x600 kernel/rcu/tree.c:4023
2 locks held by kworker/1:9/4868:
#0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc9000494fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
4 locks held by syz.0.193/5125:
#0: ffff888058034460 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:393
#1: ffff888070024f80 (&type->i_mutex_dir_key#10/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:793 [inline]
#1: ffff888070024f80 (&type->i_mutex_dir_key#10/1){+.+.}-{3:3}, at: filename_create+0x1f2/0x450 fs/namei.c:3876
#2: ffff888070024bc8 (&jfs_ip->commit_mutex){+.+.}-{3:3}, at: jfs_mkdir+0x1f8/0xa70 fs/jfs/namei.c:233
#3: ffff888070020b08 (&jfs_ip->commit_mutex/1){+.+.}-{3:3}, at: jfs_mkdir+0x213/0xa70 fs/jfs/namei.c:234
5 locks held by kworker/u4:20/5674:
3 locks held by syz-executor/6035:
#0: ffffffff8dd42428 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
#0: ffffffff8dd42428 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x740/0xed0 net/core/rtnetlink.c:6150
#1: ffff88804f5313e8 (&wg->device_update_lock){+.+.}-{3:3}, at: wg_open+0x223/0x420 drivers/net/wireguard/device.c:49
#2: ffffffff8cb308b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
#2: ffffffff8cb308b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x455/0x830 kernel/rcu/tree_exp.h:962
1 lock held by syz-executor/6169:
#0: ffffffff8dd42428 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
#0: ffffffff8dd42428 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x740/0xed0 net/core/rtnetlink.c:6150
3 locks held by kworker/0:16/6397:
#0: ffff88802e9cb138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#1: ffffc90004327d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
#2: ffffffff8dd42428 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x14d0 net/ipv6/addrconf.c:4131
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xeee/0xf30 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5657 Comm: kworker/u4:19 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:lock_is_held include/linux/lockdep.h:283 [inline]
RIP: 0010:get_freelist mm/slub.c:2969 [inline]
RIP: 0010:___slab_alloc+0x294/0x1230 mm/slub.c:3064
Code: 00 83 3d 32 71 4f 0c 00 74 3a 4c 8b 3b 49 83 c7 20 e8 10 3d 47 08 41 89 c5 83 f8 08 0f 83 35 05 00 00 4e 03 3c ed 80 49 5e 8c <4c> 89 ff be ff ff ff ff e8 af 2a 47 08 85 c0 4c 8b 6c 24 20 0f 84
RSP: 0018:ffffc900032079a0 EFLAGS: 00000082
RAX: 0000000000000001 RBX: ffff888017442140 RCX: 4ee3fdca1fb44000
RDX: 0000000000000000 RSI: ffffffff8adefcc0 RDI: ffffffff8adefc80
RBP: ffffea0001d7e200 R08: dffffc0000000000 R09: fffffbfff215c449
R10: fffffbfff215c449 R11: 1ffffffff215c448 R12: ffff888066d71dc0
R13: 0000000000000001 R14: ffffffff7fff0000 R15: ffff8880b8f3e840
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f73f8394eb8 CR3: 000000007e42b000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__slab_alloc mm/slub.c:3240 [inline]
slab_alloc_node mm/slub.c:3325 [inline]
__kmem_cache_alloc_node+0x1a0/0x260 mm/slub.c:3398
__do_kmalloc_node mm/slab_common.c:935 [inline]
__kmalloc_node_track_caller+0x9e/0x230 mm/slab_common.c:956
kmalloc_reserve net/core/skbuff.c:446 [inline]
__alloc_skb+0x22a/0x7e0 net/core/skbuff.c:515
alloc_skb include/linux/skbuff.h:1271 [inline]
nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:748 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline]
nsim_dev_trap_report_work+0x28f/0xaf0 drivers/net/netdevsim/dev.c:851
process_one_work+0x898/0x1160 kernel/workqueue.c:2292
worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295