INFO: task syz.0.781:9614 blocked for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.781 state:D stack:25352 pid:9614 tgid:9613 ppid:5825 task_flags:0x480140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0xfee/0x6120 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7008 schedule_timeout+0x1b2/0x280 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:100 [inline] __wait_for_common+0x2e7/0x4c0 kernel/sched/completion.c:121 __debugfs_file_removed fs/debugfs/inode.c:751 [inline] remove_one+0x312/0x420 fs/debugfs/inode.c:758 __simple_recursive_removal+0x148/0x5c0 fs/libfs.c:625 debugfs_remove+0x5d/0x80 fs/debugfs/inode.c:781 nsim_dev_health_exit+0x3b/0xe0 drivers/net/netdevsim/health.c:227 nsim_dev_reload_destroy+0x144/0x4a0 drivers/net/netdevsim/dev.c:1767 nsim_drv_remove+0x52/0x1e0 drivers/net/netdevsim/dev.c:1779 device_remove+0xcb/0x180 drivers/base/dd.c:631 __device_release_driver drivers/base/dd.c:1344 [inline] device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1367 bus_remove_device+0x2bc/0x560 drivers/base/bus.c:657 device_del+0x376/0x9b0 drivers/base/core.c:3879 device_unregister+0x1d/0xe0 drivers/base/core.c:3920 nsim_bus_dev_del drivers/net/netdevsim/bus.c:491 [inline] del_device_store+0x346/0x480 drivers/net/netdevsim/bus.c:244 bus_attr_store+0x74/0xb0 drivers/base/bus.c:172 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1070 fs/read_write.c:688 ksys_write+0x12a/0x250 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6fc579c819 RSP: 002b:00007f6fc669b028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f6fc5a15fa0 RCX: 00007f6fc579c819 RDX: 0000000000000045 RSI: 0000200000000040 RDI: 0000000000000008 RBP: 00007f6fc5832c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6fc5a16038 R14: 00007f6fc5a15fa0 R15: 00007ffe68477868 INFO: task syz.1.782:9617 blocked for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.782 state:D stack:29000 pid:9617 tgid:9615 ppid:5822 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0xfee/0x6120 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7008 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7065 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776 devlink_health_report+0x681/0xb50 net/devlink/health.c:680 nsim_dev_health_break_write+0x166/0x210 drivers/net/netdevsim/health.c:162 full_proxy_write+0x135/0x1a0 fs/debugfs/file.c:388 vfs_write+0x2aa/0x1070 fs/read_write.c:686 ksys_write+0x12a/0x250 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fedaf39c819 RSP: 002b:00007fedb0242028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fedaf616090 RCX: 00007fedaf39c819 RDX: 00000000000001e1 RSI: 0000200000000080 RDI: 0000000000000008 RBP: 00007fedaf432c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fedaf616128 R14: 00007fedaf616090 R15: 00007ffe89f6a448 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e7e7760 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8e7e7760 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8e7e7760 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775 1 lock held by syz-executor/5824: 3 locks held by kworker/1:4/5918: 3 locks held by kworker/u8:22/7586: 2 locks held by getty/8087: #0: ffff8880332db0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900047b32f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x1500 drivers/tty/n_tty.c:2211 1 lock held by syz-executor/9111: #0: ffffffff8e7f32b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343 8 locks held by syz.0.781/9614: #0: ffff888027dd15f8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1261 #1: ffff888036fae420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:740 #2: ffff88805eef9488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 #3: ffff888029706e18 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #3: ffff888029706e18 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344 #4: ffffffff8fb6f208 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234 #5: ffff88802033e130 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline] #5: ffff88802033e130 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1166 [inline] #5: ffff88802033e130 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb2/0x620 drivers/base/dd.c:1364 #6: ffff88807d185250 (&devlink->lock_key#6){+.+.}-{4:4}, at: nsim_drv_remove+0x4a/0x1e0 drivers/net/netdevsim/dev.c:1778 #7: ffff88805c42da70 (&sb->s_type->i_mutex_key#10/2){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline] #7: ffff88805c42da70 (&sb->s_type->i_mutex_key#10/2){+.+.}-{4:4}, at: __simple_recursive_removal+0xe0/0x5c0 fs/libfs.c:621 3 locks held by syz.1.782/9617: #0: ffff88802a7abeb8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1261 #1: ffff8880202a8420 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:740 #2: ffff88807d185250 (&devlink->lock_key#6){+.+.}-{4:4}, at: devlink_health_report+0x681/0xb50 net/devlink/health.c:680 4 locks held by syz-executor/9774: #0: ffff888036fae420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:740 #1: ffff88805fdc3088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 #2: ffff888029706e18 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888029706e18 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344 #3: ffffffff8fb6f208 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/9778: #0: ffff888036fae420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:740 #1: ffff88803478c488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 #2: ffff888029706e18 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888029706e18 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344 #3: ffffffff8fb6f208 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/9885: #0: ffff888036fae420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:740 #1: ffff88806095fc88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 #2: ffff888029706e18 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888029706e18 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344 #3: ffffffff8fb6f208 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/9896: #0: ffff888036fae420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:740 #1: ffff88806018c088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 #2: ffff888029706e18 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888029706e18 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344 #3: ffffffff8fb6f208 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/9911: #0: ffff888036fae420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:740 #1: ffff888029958888 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 #2: ffff888029706e18 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888029706e18 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344 #3: ffffffff8fb6f208 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/9922: #0: ffff888036fae420 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:740 #1: ffff8880680b9888 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 #2: ffff888029706e18 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888029706e18 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:344 #3: ffffffff8fb6f208 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x480 drivers/net/netdevsim/bus.c:234 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x141/0x190 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline] watchdog+0xd25/0x1050 kernel/hung_task.c:515 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 8497 Comm: kworker/u8:37 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x17/0x70 kernel/kcov.c:217 Code: 02 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 65 8b 05 a5 bc 05 12 48 8b 34 24 65 48 8b 15 81 bc 05 12 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 c3 cc cc RSP: 0018:ffffc9000cff7b48 EFLAGS: 00000216 RAX: 0000000080000001 RBX: 0000000000000031 RCX: ffffffff89685807 RDX: ffff8880332a3d00 RSI: ffffffff896857a8 RDI: ffff8880332a3d00 RBP: ffffffff8c7d2740 R08: 0000000000000001 R09: 000000000000002e R10: 0000000000000031 R11: c4751288c3ac5336 R12: 0000000000000000 R13: 0000000000000000 R14: dffffc0000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124440000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005590e85beee8 CR3: 00000000355f2000 CR4: 00000000003526f0 Call Trace: in_aton+0x98/0x150 net/core/utils.c:62 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:834 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline] nsim_dev_trap_report_work+0x54e/0xd10 drivers/net/netdevsim/dev.c:922 process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276 process_scheduled_works kernel/workqueue.c:3359 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245