INFO: task syz.4.373:6461 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.373 state:D stack:28688 pid: 6461 ppid: 4196 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537 rwsem_down_read_slowpath+0x548/0x9d0 kernel/locking/rwsem.c:1055 __down_read_common kernel/locking/rwsem.c:1239 [inline] __down_read kernel/locking/rwsem.c:1252 [inline] down_read+0x96/0x2e0 kernel/locking/rwsem.c:1500 iterate_supers+0xa4/0x1d0 fs/super.c:716 ksys_sync+0x9d/0x170 fs/sync.c:102 __ia32_sys_sync+0xa/0x10 fs/sync.c:113 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fe47e9d7629 RSP: 002b:00007fe47cc31028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007fe47ec50fa0 RCX: 00007fe47e9d7629 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fe47ec50fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe47ec51038 R14: 00007fe47ec50fa0 R15: 00007ffff3469bf8 Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8c31eaa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 2 locks held by getty/3945: #0: ffff88814ca27098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252 #1: ffffc90002cf62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5df/0x1a70 drivers/tty/n_tty.c:2158 4 locks held by kworker/1:7/4228: #0: ffff888142f94138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1 #1: ffffc9000307fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285 #2: ffff888147e66220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline] #2: ffff888147e66220 (&dev->mutex){....}-{3:3}, at: hub_event+0x19f/0x55e0 drivers/usb/core/hub.c:5827 #3: ffff8880760d4220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline] #3: ffff8880760d4220 (&dev->mutex){....}-{3:3}, at: usb_disconnect+0x107/0x8a0 drivers/usb/core/hub.c:2278 3 locks held by kworker/0:8/4417: #0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1 #1: ffffc90003ebfd00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285 #2: ffffffff8c323430 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0xa1/0x4c0 kernel/rcu/tree.c:4043 2 locks held by kworker/0:14/4426: #0: ffff888016c72138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1 #1: ffffc90003f47d00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285 3 locks held by kworker/0:15/4428: #0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1 #1: ffffc90003f6fd00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285 #2: ffffffff8c323430 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0xa1/0x4c0 kernel/rcu/tree.c:4043 4 locks held by syz.3.71/4764: #0: ffff88807991a0e0 (&type->s_umount_key#25/1){+.+.}-{3:3}, at: alloc_super+0x201/0x950 fs/super.c:229 #1: ffff88805f4782e0 (&type->i_mutex_dir_key#12){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline] #1: ffff88805f4782e0 (&type->i_mutex_dir_key#12){+.+.}-{3:3}, at: reiserfs_xattr_init+0x1de/0x720 fs/reiserfs/xattr.c:1011 #2: ffffc900032710f0 (&journal->j_mutex){+.+.}-{3:3}, at: reiserfs_mutex_lock_safe fs/reiserfs/reiserfs.h:814 [inline] #2: ffffc900032710f0 (&journal->j_mutex){+.+.}-{3:3}, at: lock_journal fs/reiserfs/journal.c:534 [inline] #2: ffffc900032710f0 (&journal->j_mutex){+.+.}-{3:3}, at: do_journal_end+0x304/0x42d0 fs/reiserfs/journal.c:4025 #3: ffff888022f2ac90 (&jl->j_commit_mutex){+.+.}-{3:3}, at: reiserfs_mutex_lock_safe fs/reiserfs/reiserfs.h:814 [inline] #3: ffff888022f2ac90 (&jl->j_commit_mutex){+.+.}-{3:3}, at: flush_commit_list+0x6de/0x1d70 fs/reiserfs/journal.c:1005 1 lock held by syz.4.373/6461: #0: ffff88807991a0e0 (&type->s_umount_key#111){++++}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:716 2 locks held by syz.5.1107/9918: #0: ffff8880208d8518 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf9/0x7d0 block/bdev.c:915 #1: ffff88814726c468 (&lo->lo_mutex){+.+.}-{3:3}, at: lo_release+0x4d/0x1f0 drivers/block/loop.c:2071 2 locks held by dhcpcd/9923: #0: ffff888052431410 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline] #0: ffff888052431410 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:650 [inline] #0: ffff888052431410 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x90/0x240 net/socket.c:1345 #1: ffffffff8c323528 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline] #1: ffffffff8c323528 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3a5/0x750 kernel/rcu/tree_exp.h:845 2 locks held by dhcpcd/9927: #0: ffff888052434410 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline] #0: ffff888052434410 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:650 [inline] #0: ffff888052434410 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x90/0x240 net/socket.c:1345 #1: ffffffff8c323528 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline] #1: ffffffff8c323528 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2d1/0x750 kernel/rcu/tree_exp.h:845 1 lock held by dhcpcd/9928: #0: ffff888037572120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1744 [inline] #0: ffff888037572120 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x35/0xda0 net/packet/af_packet.c:3212 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 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+0x188/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a2/0x3d0 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4384 Comm: kworker/u4:7 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Workqueue: bat_events batadv_nc_worker RIP: 0010:lockdep_recursion_inc kernel/locking/lockdep.c:431 [inline] RIP: 0010:lockdep_hardirqs_on_prepare+0x1c1/0x770 kernel/locking/lockdep.c:4277 Code: 48 89 f8 48 c1 e8 03 80 3c 10 00 74 05 e8 27 61 61 00 4c 8b 74 24 10 49 89 9e c8 0a 00 00 48 c7 c7 80 35 2b 8a e8 5f 6c 5f 08 <65> ff 05 a8 ab a5 7e 49 8d 9e e8 0a 00 00 49 89 de 49 c1 ee 03 48 RSP: 0018:ffffc9000356f9c0 EFLAGS: 00000082 RAX: 0000000000000000 RBX: 81436a5c2614cd83 RCX: 0e01348b52d18600 RDX: dffffc0000000000 RSI: ffffffff8a2b3580 RDI: ffffffff8a79f800 RBP: ffffc9000356fa80 R08: ffff888077f08743 R09: 1ffff1100efe10e8 R10: dffffc0000000000 R11: ffffed100efe10e9 R12: ffffffff89912aa6 R13: dffffc0000000000 R14: ffff88802a998000 R15: 1ffff920006adf54 FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000558edbe77660 CR3: 0000000044d5a000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: trace_hardirqs_on+0x67/0x80 kernel/trace/trace_preemptirq.c:49 __local_bh_enable_ip+0x136/0x1c0 kernel/softirq.c:406 spin_unlock_bh include/linux/spinlock.h:409 [inline] batadv_nc_purge_paths+0x316/0x3b0 net/batman-adv/network-coding.c:475 batadv_nc_worker+0x327/0x5c0 net/batman-adv/network-coding.c:726 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287