INFO: task syz.8.18578:13111 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.8.18578 state:D stack:25160 pid:13111 tgid:13111 ppid:29539 task_flags:0x400040 flags:0x00080003 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 request_wait_answer fs/fuse/dev.c:585 [inline] __fuse_request_send fs/fuse/dev.c:599 [inline] __fuse_simple_request+0x11d2/0x1bb0 fs/fuse/dev.c:693 fuse_simple_request fs/fuse/fuse_i.h:1250 [inline] fuse_flush+0x5dd/0x810 fs/fuse/file.c:482 filp_flush+0xc0/0x190 fs/open.c:1549 filp_close+0x1d/0x40 fs/open.c:1562 __range_close fs/file.c:767 [inline] __do_sys_close_range fs/file.c:826 [inline] __se_sys_close_range+0x35c/0x650 fs/file.c:790 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f897adbf6c9 RSP: 002b:00007ffc2f5d3a08 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: ffffffffffffffda RBX: 00000000000fa941 RCX: 00007f897adbf6c9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f897b017da0 R08: 0000000000000001 R09: 0000000b2f5d3cff R10: 0000001b30920000 R11: 0000000000000246 R12: 00007f897b015fac R13: 00007f897b015fa0 R14: ffffffffffffffff R15: 00007ffc2f5d3b20 Showing all locks held in the system: 2 locks held by rcuc/0/20: 4 locks held by rcuc/1/28: 1 lock held by khungtaskd/38: #0: ffffffff8d5aa840 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8d5aa840 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8d5aa840 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by getty/5562: #0: ffff88823bf348a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003e762e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1400 drivers/tty/n_tty.c:2222 4 locks held by syz-executor/5787: 3 locks held by syz-executor/5802: 1 lock held by syz-executor/5810: 3 locks held by kworker/1:4/5874: 3 locks held by kworker/0:2/28876: 1 lock held by syz.7.19506/15387: #0: ffffffff99066f88 (nfnl_subsys_ipset){+.+.}-{4:4}, at: call_ad+0x176/0x9c0 net/netfilter/ipset/ip_set_core.c:1746 2 locks held by syz.9.19542/15480: 1 lock held by syz.1.19555/15504: 4 locks held by syz.1.19555/15509: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline] watchdog+0xf60/0xfa0 kernel/hung_task.c:495 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 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: 28876 Comm: kworker/0:2 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: events free_obj_work RIP: 0010:unwind_next_frame+0x19ae/0x2390 arch/x86/kernel/unwind_orc.c:680 Code: c7 c0 70 e8 8a be 80 03 00 00 48 c7 c2 60 71 e8 8a e8 66 82 28 00 48 c7 c7 40 a8 5a 8d 4c 89 fe e8 47 68 28 00 e8 12 23 32 00 <89> d8 48 81 c4 98 00 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d e9 4a 89 RSP: 0018:ffffc90003a2f4b8 EFLAGS: 00000287 RAX: 0000000000000000 RBX: ffffffff8f5ec301 RCX: 790abedbdb632700 RDX: 0000000000000002 RSI: ffffffff8cf6435e RDI: ffff88802903da00 RBP: dffffc0000000000 R08: ffffc90003a2fe50 R09: 0000000000000000 R10: ffffc90003a2f5d8 R11: fffff52000745ebd R12: ffffc90003a2fe60 R13: ffffc90003a28000 R14: ffffc90003a2f588 R15: ffffffff81737cf5 FS: 0000000000000000(0000) GS:ffff888126df9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000159030 CR3: 0000000061f60000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000006800 DR2: 0000000000009951 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587 kasan_save_free_info mm/kasan/kasan.h:406 [inline] poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2539 [inline] slab_free mm/slub.c:6630 [inline] kmem_cache_free+0x19a/0x910 mm/slub.c:6740 free_object_list lib/debugobjects.c:326 [inline] free_obj_work+0x377/0x4a0 lib/debugobjects.c:513 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245