INFO: task syz.4.613:7734 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.613 state:D stack:28128 pid:7734 tgid:7730 ppid:5826 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5264 [inline] __schedule+0x1836/0x4ed0 kernel/sched/core.c:6872 __schedule_loop kernel/sched/core.c:6954 [inline] schedule+0x165/0x360 kernel/sched/core.c:6969 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7026 rwsem_down_write_slowpath+0x872/0xfe0 kernel/locking/rwsem.c:1185 __down_write_common kernel/locking/rwsem.c:1317 [inline] __down_write kernel/locking/rwsem.c:1326 [inline] down_write_nested+0x1b5/0x200 kernel/locking/rwsem.c:1707 inode_lock_nested include/linux/fs.h:1096 [inline] filename_create+0x1f8/0x3c0 fs/namei.c:4226 do_mkdirat+0xa0/0x650 fs/namei.c:4478 __do_sys_mkdir fs/namei.c:4508 [inline] __se_sys_mkdir fs/namei.c:4506 [inline] __x64_sys_mkdir+0x6c/0x80 fs/namei.c:4506 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: 0033:0x7fb35238f6c9 RSP: 002b:00007fb35313f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000053 RAX: ffffffffffffffda RBX: 00007fb3525e6090 RCX: 00007fb35238f6c9 RDX: 0000000000000000 RSI: 0000000000000105 RDI: 0000200000000500 RBP: 00007fb352411f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb3525e6128 R14: 00007fb3525e6090 R15: 00007fff791cd448 INFO: task syz.4.613:7735 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.613 state:D stack:24264 pid:7735 tgid:7730 ppid:5826 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5264 [inline] __schedule+0x1836/0x4ed0 kernel/sched/core.c:6872 __schedule_loop kernel/sched/core.c:6954 [inline] schedule+0x165/0x360 kernel/sched/core.c:6969 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7026 rwsem_down_write_slowpath+0x872/0xfe0 kernel/locking/rwsem.c:1185 __down_write_common kernel/locking/rwsem.c:1317 [inline] __down_write kernel/locking/rwsem.c:1326 [inline] down_write_nested+0x1b5/0x200 kernel/locking/rwsem.c:1707 inode_lock_nested include/linux/fs.h:1096 [inline] filename_create+0x1f8/0x3c0 fs/namei.c:4226 do_mkdirat+0xa0/0x650 fs/namei.c:4478 __do_sys_mkdir fs/namei.c:4508 [inline] __se_sys_mkdir fs/namei.c:4506 [inline] __x64_sys_mkdir+0x6c/0x80 fs/namei.c:4506 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: 0033:0x7fb35238f6c9 RSP: 002b:00007fb3505f6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000053 RAX: ffffffffffffffda RBX: 00007fb3525e6180 RCX: 00007fb35238f6c9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00002000000020c0 RBP: 00007fb352411f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb3525e6218 R14: 00007fb3525e6180 R15: 00007fff791cd448 INFO: task syz.4.613:7739 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.613 state:D stack:28744 pid:7739 tgid:7730 ppid:5826 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5264 [inline] __schedule+0x1836/0x4ed0 kernel/sched/core.c:6872 __schedule_loop kernel/sched/core.c:6954 [inline] schedule+0x165/0x360 kernel/sched/core.c:6969 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7026 rwsem_down_write_slowpath+0x872/0xfe0 kernel/locking/rwsem.c:1185 __down_write_common kernel/locking/rwsem.c:1317 [inline] __down_write kernel/locking/rwsem.c:1326 [inline] down_write_nested+0x1b5/0x200 kernel/locking/rwsem.c:1707 inode_lock_nested include/linux/fs.h:1096 [inline] do_rmdir+0x1b2/0x550 fs/namei.c:4595 __do_sys_rmdir fs/namei.c:4622 [inline] __se_sys_rmdir fs/namei.c:4620 [inline] __x64_sys_rmdir+0x47/0x50 fs/namei.c:4620 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: 0033:0x7fb35238f6c9 RSP: 002b:00007fb3501d3038 EFLAGS: 00000246 ORIG_RAX: 0000000000000054 RAX: ffffffffffffffda RBX: 00007fb3525e6270 RCX: 00007fb35238f6c9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000100 RBP: 00007fb352411f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb3525e6308 R14: 00007fb3525e6270 R15: 00007fff791cd448 Showing all locks held in the system: 1 lock held by ksoftirqd/0/15: 1 lock held by khungtaskd/31: #0: ffffffff8df3d820 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df3d820 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8df3d820 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:8/3540: 2 locks held by getty/5580: #0: ffff88814d5d90a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900036c32f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 4 locks held by kworker/u8:10/6827: 2 locks held by syz.4.613/7731: 2 locks held by syz.4.613/7734: #0: ffff88807b832420 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:498 #1: ffff888058a488f0 (&type->i_mutex_dir_key#11/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1096 [inline] #1: ffff888058a488f0 (&type->i_mutex_dir_key#11/1){+.+.}-{4:4}, at: filename_create+0x1f8/0x3c0 fs/namei.c:4226 2 locks held by syz.4.613/7735: #0: ffff88807b832420 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:498 #1: ffff888058a488f0 (&type->i_mutex_dir_key#11/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1096 [inline] #1: ffff888058a488f0 (&type->i_mutex_dir_key#11/1){+.+.}-{4:4}, at: filename_create+0x1f8/0x3c0 fs/namei.c:4226 2 locks held by syz.4.613/7739: #0: ffff88807b832420 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:498 #1: ffff888058a488f0 (&type->i_mutex_dir_key#11/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1096 [inline] #1: ffff888058a488f0 (&type->i_mutex_dir_key#11/1){+.+.}-{4:4}, at: do_rmdir+0x1b2/0x550 fs/namei.c:4595 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 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:336 [inline] watchdog+0xfa8/0xff0 kernel/hung_task.c:499 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 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: 37 Comm: kworker/u8:3 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:lock_release+0x80/0x3d0 kernel/locking/lockdep.c:5881 Code: 05 e0 0d 00 0f 84 44 02 00 00 65 8b 05 f9 7a d7 10 85 c0 0f 85 35 02 00 00 65 4c 8b 3c 25 08 40 75 92 41 83 bf 2c 0b 00 00 00 <0f> 85 1e 02 00 00 49 81 3e c0 f3 38 93 0f 84 11 02 00 00 48 c7 44 RSP: 0018:ffffc90000007750 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffffff90692801 RCX: c7da264d135aa700 RDX: ffffc90000007801 RSI: ffffffff8bbf4140 RDI: ffffffff8bbf4100 RBP: dffffc0000000000 R08: ffffc90000ad7a70 R09: 0000000000000000 R10: ffffc900000078d8 R11: fffff52000000f1d R12: ffffc90000ad7a80 R13: ffffffff8173cfd5 R14: ffffffff8df3d820 R15: ffff8881416c9e80 FS: 0000000000000000(0000) GS:ffff888125ecc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7c8c5b4198 CR3: 000000001b706000 CR4: 00000000003526f0 Call Trace: rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:897 [inline] class_rcu_destructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0x19a9/0x2390 arch/x86/kernel/unwind_orc.c:680 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:584 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_after_rcu_debug+0x12c/0x2a0 mm/slub.c:6720 rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core+0xcab/0x1770 kernel/rcu/tree.c:2861 handle_softirqs+0x27d/0x880 kernel/softirq.c:626 do_softirq+0xec/0x180 kernel/softirq.c:523 __local_bh_enable_ip+0x17d/0x1c0 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:396 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:835 [inline] nsim_dev_trap_report_work+0x7c7/0xb80 drivers/net/netdevsim/dev.c:866 process_one_work+0x93a/0x15e0 kernel/workqueue.c:3261 process_scheduled_works kernel/workqueue.c:3344 [inline] worker_thread+0x9b0/0xee0 kernel/workqueue.c:3425 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245