INFO: task syz.5.3945:18580 blocked for more than 148 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.5.3945 state:D stack:24600 pid:18580 tgid:18580 ppid:11146 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7340 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0x7f7/0x1550 kernel/locking/mutex.c:820 tty_release_struct+0xae/0xd0 drivers/tty/tty_io.c:1691 tty_release+0xcb0/0x1710 drivers/tty/tty_io.c:1852 __fput+0x44f/0xa60 fs/file_table.c:510 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:67 [inline] exit_to_user_mode_loop+0xf3/0x4d0 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f780659ce59 RSP: 002b:00007f780693fba8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f7806817da0 RCX: 00007f780659ce59 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f7806817da0 R08: 0000000000000006 R09: 0000000000000000 R10: 00007f7806817cb0 R11: 0000000000000246 R12: 00000000000bdf84 R13: 00007f780681618c R14: 00000000000bdd0e R15: 00007f7806816180 Showing all locks held in the system: 1 lock held by kthreadd/2: 2 locks held by kworker/1:0/24: 1 lock held by khungtaskd/30: #0: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 1 lock held by kcompactd0/33: 3 locks held by kworker/u8:2/35: 2 locks held by kworker/1:1/42: 3 locks held by kswapd0/85: 4 locks held by kworker/u8:6/141: 2 locks held by kworker/1:2/808: 6 locks held by kworker/R-bat_e/3229: 4 locks held by kworker/u8:8/3289: 1 lock held by klogd/4983: 4 locks held by udevd/4994: 2 locks held by dhcpcd/5288: 1 lock held by crond/5364: 2 locks held by getty/5385: #0: ffff8880372f70a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0 drivers/tty/n_tty.c:2211 2 locks held by syz-executor/5612: 4 locks held by kworker/0:4/5703: 4 locks held by kworker/u8:11/6390: 3 locks held by kworker/u8:12/6391: 3 locks held by kworker/u8:13/6392: 3 locks held by kworker/u8:14/6393: 4 locks held by kworker/u8:15/6394: 4 locks held by kworker/u8:16/6395: 4 locks held by kworker/u8:17/6396: 4 locks held by kworker/u8:18/6397: 4 locks held by kworker/u8:19/9108: 4 locks held by kworker/u8:20/9109: 4 locks held by kworker/u8:21/9110: 3 locks held by kworker/0:1/11448: 4 locks held by kworker/1:3/14621: 5 locks held by syz-executor/15267: 3 locks held by kworker/u8:0/15425: 1 lock held by syz-executor/15551: 3 locks held by kworker/u8:1/16823: 7 locks held by kworker/u8:3/16824: 4 locks held by kworker/u8:4/16825: 4 locks held by kworker/u8:5/16826: 1 lock held by syz.5.3417/16986: #0: ffffffff8f202e40 (tty_mutex){+.+.}-{4:4}, at: tty_release_struct+0xae/0xd0 drivers/tty/tty_io.c:1691 1 lock held by syz.2.3944/18582: 1 lock held by syz.5.3945/18580: #0: ffffffff8f202e40 (tty_mutex){+.+.}-{4:4}, at: tty_release_struct+0xae/0xd0 drivers/tty/tty_io.c:1691 3 locks held by syz.4.3947/18590: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 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:162 [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:353 [inline] watchdog+0xfd3/0x1030 kernel/hung_task.c:561 kthread+0x389/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 3229 Comm: kworker/R-bat_e Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: bat_events batadv_dat_purge RIP: 0010:lock_release+0x5/0x3c0 kernel/locking/lockdep.c:5876 Code: e9 70 fe ff ff 41 be 2f 00 00 00 e9 0e ff ff ff 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 <41> 57 41 56 41 55 41 54 53 48 83 ec 30 49 89 f5 49 89 fe 65 48 8b RSP: 0018:ffffc90000006ea8 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffffc90000006f01 RCX: 0000000080000102 RDX: 0000000000000000 RSI: ffffffff8176f256 RDI: ffffffff8e95cda0 RBP: dffffc0000000000 R08: ffffc90000006fe7 R09: 0000000000000000 R10: ffffc90000006fd8 R11: fffff52000000dfd R12: ffffc9000d6e7a20 R13: 1ffff92000000df3 R14: ffffc90000006f88 R15: ffffffff8176f256 FS: 0000000000000000(0000) GS:ffff88812528a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0e2c7eb078 CR3: 0000000090414000 CR4: 00000000003526f0 DR0: 0000000080000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: rcu_lock_release include/linux/rcupdate.h:310 [inline] rcu_read_unlock include/linux/rcupdate.h:869 [inline] class_rcu_destructor include/linux/rcupdate.h:1181 [inline] unwind_next_frame+0x1bba/0x2550 arch/x86/kernel/unwind_orc.c:709 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 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2689 [inline] slab_free mm/slub.c:6250 [inline] kmem_cache_free+0x182/0x650 mm/slub.c:6377 nft_synproxy_eval_v6+0x352/0x4e0 net/netfilter/nft_synproxy.c:92 nft_synproxy_do_eval+0x3ce/0x580 net/netfilter/nft_synproxy.c:146 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x48d/0x1ae0 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0x360/0x4b0 net/netfilter/nft_chain_filter.c:162 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:316 ip6_input+0x16a/0x270 net/ipv6/ip6_input.c:545 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6202 [inline] __netif_receive_skb net/core/dev.c:6315 [inline] process_backlog+0x7dd/0x1950 net/core/dev.c:6666 __napi_poll+0xae/0x340 net/core/dev.c:7733 napi_poll net/core/dev.c:7796 [inline] net_rx_action+0x627/0xf70 net/core/dev.c:7953 handle_softirqs+0x22a/0x840 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:396 [inline] __batadv_dat_purge net/batman-adv/distributed-arp-table.c:185 [inline] batadv_dat_purge+0x2da/0x3c0 net/batman-adv/distributed-arp-table.c:204 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397 rescuer_thread+0x827/0x1130 kernel/workqueue.c:3621 kthread+0x389/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245