INFO: task kworker/u4:2:151 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:2 state:D stack:21128 pid: 151 ppid: 2 flags:0x00004000 Workqueue: writeback wb_workfn (flush-7:0) Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537 __mutex_lock_common+0xc71/0x2390 kernel/locking/mutex.c:669 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 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:1505 [inline] __writeback_single_inode+0x6c3/0xda0 fs/fs-writeback.c:1715 writeback_sb_inodes+0x9fe/0x1610 fs/fs-writeback.c:1940 __writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:2011 wb_writeback+0x455/0xb90 fs/fs-writeback.c:2116 wb_check_background_flush fs/fs-writeback.c:2182 [inline] wb_do_writeback fs/fs-writeback.c:2270 [inline] wb_workfn+0xb47/0xe60 fs/fs-writeback.c:2298 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Showing all locks held in the system: 4 locks held by kworker/u4:0/9: #0: ffff888142bc8938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1 #1: ffffc90000ce7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285 #2: ffff8880596500e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418 #3: ffff88805f214288 (&jfs_ip->commit_mutex){+.+.}-{3:3}, at: jfs_commit_inode+0x1c7/0x520 fs/jfs/inode.c:102 1 lock held by khungtaskd/27: #0: ffffffff8c11c720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 4 locks held by kworker/u4:1/144: #0: ffff888142bc8938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1 #1: ffffc9000173fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285 #2: ffff88801fd4a0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418 #3: ffff88805f2101c8 (&jfs_ip->commit_mutex){+.+.}-{3:3}, at: jfs_commit_inode+0x1c7/0x520 fs/jfs/inode.c:102 4 locks held by kworker/u4:2/151: #0: ffff888142bc8938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1 #1: ffffc90001e37d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285 #2: ffff88807b3880e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418 #3: ffff88807132b008 (&jfs_ip->commit_mutex){+.+.}-{3:3}, at: jfs_commit_inode+0x1c7/0x520 fs/jfs/inode.c:102 4 locks held by kworker/u4:3/415: #0: ffff888142bc8938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1 #1: ffffc9000310fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285 #2: ffff8880786420e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418 #3: ffff88805f00f0c8 (&jfs_ip->commit_mutex){+.+.}-{3:3}, at: jfs_commit_inode+0x1c7/0x520 fs/jfs/inode.c:102 2 locks held by getty/3945: #0: ffff88802c3c8098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252 #1: ffffc900025e62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158 4 locks held by kworker/u4:4/4207: #0: ffff888142bc8938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1 #1: ffffc90002eafd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285 #2: ffff88807a5b20e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418 #3: ffff88805f33b008 (&jfs_ip->commit_mutex){+.+.}-{3:3}, at: jfs_commit_inode+0x1c7/0x520 fs/jfs/inode.c:102 4 locks held by kworker/u4:5/4208: #0: ffff888142bc8938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1 #1: ffffc90002f0fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285 #2: ffff88801919a0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418 #3: ffff88805f00b008 (&jfs_ip->commit_mutex){+.+.}-{3:3}, at: jfs_commit_inode+0x1c7/0x520 fs/jfs/inode.c:102 2 locks held by kworker/0:9/4239: #0: ffff888016872138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1 #1: ffffc900030efd00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285 4 locks held by syz.0.16/5053: 4 locks held by syz.1.17/5078: 4 locks held by syz.2.18/5099: 4 locks held by kworker/u4:7/5116: #0: ffff888142bc8938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1 #1: ffffc9000350fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285 #2: ffff888023bbc0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418 #3: ffff88805f078b08 (&jfs_ip->commit_mutex){+.+.}-{3:3}, at: jfs_commit_inode+0x1c7/0x520 fs/jfs/inode.c:102 4 locks held by syz.3.19/5123: 3 locks held by kworker/u4:8/5146: #0: ffff888016879138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1 #1: ffffc900035ffd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285 #2: ffffffff8d238748 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:251 4 locks held by syz.4.20/5159: 4 locks held by syz.5.21/5188: 3 locks held by kworker/u4:10/5189: 4 locks held by kworker/u4:11/5217: #0: ffff888142bc8938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1 #1: ffffc9000380fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285 #2: ffff88802bab40e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418 #3: ffff88805f33f0c8 (&jfs_ip->commit_mutex){+.+.}-{3:3}, at: jfs_commit_inode+0x1c7/0x520 fs/jfs/inode.c:102 4 locks held by syz.6.22/5219: 3 locks held by kworker/u4:12/5240: 4 locks held by syz.7.23/5253: 2 locks held by syz-executor/5255: #0: ffffffff8d238748 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline] #0: ffffffff8d238748 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647 #1: ffffffff8c1211a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline] #1: ffffffff8c1211a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x347/0x6b0 kernel/rcu/tree_exp.h:845 ============================================= 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 10/02/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline] watchdog+0xe0f/0xe50 kernel/hung_task.c:369 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 5240 Comm: kworker/u4:12 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: phy14 ieee80211_iface_work RIP: 0010:lock_release+0x1/0x870 kernel/locking/lockdep.c:5631 Code: d9 80 e1 07 80 c1 03 38 c1 0f 8c c1 f8 ff ff 48 89 df e8 62 b8 5f 00 e9 b4 f8 ff ff bb 2f 00 00 00 e9 ca f8 ff ff 0f 1f 00 55 <48> 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec e0 00 00 RSP: 0018:ffffc9000393f990 EFLAGS: 00000293 RAX: ffffffff8934bfaa RBX: 0000000000000001 RCX: ffff888022d30000 RDX: 0000000000000000 RSI: ffffffff8934bfa5 RDI: ffffffff8c11c720 RBP: ffffc9000393fbc0 R08: dffffc0000000000 R09: fffffbfff1ad334e R10: fffffbfff1ad334e R11: 1ffffffff1ad334d R12: ffff888078ee4c80 R13: ffff888078ee5b08 R14: ffff888061554000 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcf5eb2ad00 CR3: 0000000021f6b000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_unlock include/linux/rcupdate.h:773 [inline] ieee80211_update_sta_info net/mac80211/ibss.c:1101 [inline] ieee80211_rx_bss_info net/mac80211/ibss.c:1121 [inline] ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1614 [inline] ieee80211_ibss_rx_queued_mgmt+0x16a9/0x29c0 net/mac80211/ibss.c:1643 ieee80211_iface_process_skb net/mac80211/iface.c:1459 [inline] ieee80211_iface_work+0x70e/0xc60 net/mac80211/iface.c:1513 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287