INFO: task kworker/u8:0:12 blocked for more than 143 seconds. Not tainted 6.15.0-rc7-syzkaller-00142-g4856ebd99715 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:0 state:D stack:24136 pid:12 tgid:12 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: events_unbound netfs_write_collection_worker Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6860 bit_wait+0x15/0xe0 kernel/sched/wait_bit.c:237 __wait_on_bit+0x62/0x180 kernel/sched/wait_bit.c:49 out_of_line_wait_on_bit+0xd9/0x110 kernel/sched/wait_bit.c:64 wait_on_bit include/linux/wait_bit.h:77 [inline] netfs_retry_writes+0x300/0x1a50 fs/netfs/write_retry.c:217 netfs_collect_write_results fs/netfs/write_collect.c:352 [inline] netfs_write_collection_worker+0x23fd/0x3830 fs/netfs/write_collect.c:374 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 3 locks held by kworker/0:1/10: #0: ffff8880b8439dd8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:605 #1: ffff8880b8423c48 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x2c1/0x8e0 kernel/sched/psi.c:987 #2: ffff8880b84256d8 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x127/0x1d0 kernel/time/timer.c:1046 2 locks held by kworker/u8:0/12: #0: ffff88801b481148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc90000117d18 ((work_completion)(&rreq->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 1 lock held by khungtaskd/31: #0: ffffffff8e3bfc00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e3bfc00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e3bfc00 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6764 3 locks held by kworker/u8:5/146: #0: ffff88801b481148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc90002e4fd18 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 #2: ffffffff90128ce8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0x51/0xc0 net/core/link_watch.c:303 3 locks held by kworker/u8:8/3490: #0: ffff88814cf7a948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc9000c6e7d18 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 #2: ffffffff90128ce8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff90128ce8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x120/0x14e0 net/ipv6/addrconf.c:4198 4 locks held by kworker/u8:9/3510: #0: ffff88801c2f3948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc9000ca97d18 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 #2: ffffffff90112e50 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xc9/0xb30 net/core/net_namespace.c:608 #3: ffffffff8e3cb138 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x280/0x3c0 kernel/rcu/tree_exp.h:304 1 lock held by dhcpcd/5483: #0: ffffffff90128ce8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff90128ce8 (rtnl_mutex){+.+.}-{4:4}, at: devinet_ioctl+0x26d/0x1f50 net/ipv4/devinet.c:1121 2 locks held by getty/5579: #0: ffff88814df980a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900033432f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 3 locks held by syz.1.784/8790: #0: ffff888057e60420 (sb_writers#15){.+.+}-{0:0}, at: do_pwritev+0x1af/0x270 fs/read_write.c:1151 #1: ffff8880773a1b08 (&sb->s_type->i_mutex_key#21){++++}-{4:4}, at: netfs_start_io_write+0x59/0x80 fs/netfs/locking.c:112 #2: ffff8880773a1ec0 (&ctx->wb_lock){+.+.}-{4:4}, at: netfs_begin_writethrough+0x64/0x1c0 fs/netfs/write_issue.c:624 1 lock held by syz-executor/10258: #0: ffffffff90128ce8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff90128ce8 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_newaddr+0x4e4/0x1c70 net/ipv6/addrconf.c:5031 7 locks held by syz-executor/10417: #0: ffff888036da0420 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12a/0x240 fs/read_write.c:736 #1: ffff888031825088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x510 fs/kernfs/file.c:325 #2: ffff888144345788 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2b2/0x510 fs/kernfs/file.c:326 #3: ffffffff8f6cad28 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x4a0 drivers/net/netdevsim/bus.c:216 #4: ffff88805ab4e0e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline] #4: ffff88805ab4e0e8 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1094 [inline] #4: ffff88805ab4e0e8 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xa4/0x620 drivers/base/dd.c:1292 #5: ffff88805ab4f250 (&devlink->lock_key#2){+.+.}-{4:4}, at: nsim_drv_remove+0x4a/0x1d0 drivers/net/netdevsim/dev.c:1675 #6: ffffffff90128ce8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #6: ffffffff90128ce8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_dev_lock+0x146/0x360 net/core/dev.c:2089 1 lock held by syz-executor/10434: #0: ffffffff8e3cb138 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:336 1 lock held by syz.0.1225/10491: #0: ffffffff90128ce8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:633 [inline] #0: ffffffff90128ce8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x230 drivers/net/tun.c:3390 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc7-syzkaller-00142-g4856ebd99715 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline] watchdog+0xf70/0x12c0 kernel/hung_task.c:437 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 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: 10203 Comm: syz-executor Not tainted 6.15.0-rc7-syzkaller-00142-g4856ebd99715 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline] RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:151 [inline] RIP: 0010:lock_acquire kernel/locking/lockdep.c:5869 [inline] RIP: 0010:lock_acquire+0x1a0/0x350 kernel/locking/lockdep.c:5823 Code: da ff ff 48 c7 c7 43 ee bb 8d 48 83 c4 28 e8 c7 24 d5 09 b8 ff ff ff ff 65 0f c1 05 82 75 0c 12 83 f8 01 0f 85 6a 01 00 00 9c <58> f6 c4 02 0f 85 7f 01 00 00 48 83 3c 24 00 0f 84 ad fe ff ff fb RSP: 0018:ffffc900039f7658 EFLAGS: 00000046 RAX: 0000000000000001 RBX: ffffffff8e3bfc00 RCX: 00000000ef9d33e4 RDX: 0000000000000000 RSI: ffffffff8dbbee43 RDI: ffffffff8bf4a520 RBP: 0000000000000002 R08: 0ac0d5affe09d4ff R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124ada000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055f3c29e0da8 CR3: 0000000034ba3000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xd1/0x20a0 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x160/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x84/0x1a0 mm/page_owner.c:308 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1258 [inline] __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2721 vfree+0x176/0x960 mm/vmalloc.c:3384 kcov_put kernel/kcov.c:439 [inline] kcov_put kernel/kcov.c:435 [inline] kcov_close+0x34/0x60 kernel/kcov.c:535 __fput+0x3ff/0xb70 fs/file_table.c:465 task_work_run+0x150/0x240 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xafb/0x2c30 kernel/exit.c:953 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102 get_signal+0x2673/0x26d0 kernel/signal.c:3034 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x260 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2fdd7907fc Code: Unable to access opcode bytes at 0x7f2fdd7907d2. RSP: 002b:00007fff6f0d89a0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: 0000000000000040 RBX: 00007f2fde4e4620 RCX: 00007f2fdd7907fc RDX: 0000000000000040 RSI: 00007f2fde4e4670 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007fff6f0d89f4 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f2fde4e4670 R15: 0000000000000000