INFO: task kworker/u8:6:1142 blocked for more than 143 seconds. Not tainted 6.12.0-syzkaller-10689-g7af08b57bcb9 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:6 state:D stack:19856 pid:1142 tgid:1142 ppid:2 flags:0x00004000 Workqueue: writeback wb_workfn (flush-7:6) Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0x17fb/0x4be0 kernel/sched/core.c:6756 __schedule_loop kernel/sched/core.c:6833 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6848 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6905 rwsem_down_write_slowpath+0xeee/0x13b0 kernel/locking/rwsem.c:1176 __down_write_common kernel/locking/rwsem.c:1304 [inline] __down_write kernel/locking/rwsem.c:1313 [inline] down_write+0x1d7/0x220 kernel/locking/rwsem.c:1578 f2fs_down_write fs/f2fs/f2fs.h:2204 [inline] f2fs_balance_fs+0x5a9/0x810 fs/f2fs/segment.c:448 f2fs_write_inode+0x3a7/0x540 fs/f2fs/inode.c:802 write_inode fs/fs-writeback.c:1525 [inline] __writeback_single_inode+0x708/0x10d0 fs/fs-writeback.c:1745 writeback_sb_inodes+0x820/0x1360 fs/fs-writeback.c:1976 __writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:2047 wb_writeback+0x427/0xb80 fs/fs-writeback.c:2158 wb_check_old_data_flush fs/fs-writeback.c:2262 [inline] wb_do_writeback fs/fs-writeback.c:2315 [inline] wb_workfn+0xb94/0x1080 fs/fs-writeback.c:2343 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Showing all locks held in the system: 3 locks held by kworker/u8:0/11: #0: ffff88814d6c6148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline] #0: ffff88814d6c6148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310 #1: ffffc90000107d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc90000107d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310 #2: ffffffff8fcd5c48 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0xd0/0x16f0 net/ipv6/addrconf.c:4215 1 lock held by khungtaskd/30: #0: ffffffff8e93c560 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e93c560 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e93c560 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6744 4 locks held by kworker/u8:6/1142: #0: ffff888020699148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline] #0: ffff888020699148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310 #1: ffffc90003f3fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc90003f3fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310 #2: ffff88803529e0e0 (&type->s_umount_key#68){++++}-{4:4}, at: super_trylock_shared+0x22/0xf0 fs/super.c:562 #3: ffff888032ced350 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2204 [inline] #3: ffff888032ced350 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_balance_fs+0x5a9/0x810 fs/f2fs/segment.c:448 3 locks held by kworker/u8:7/1152: 3 locks held by kworker/u8:9/3526: #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline] #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310 #1: ffffc9000cb97d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc9000cb97d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310 #2: ffffffff8fcd5c48 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:276 1 lock held by dhcpcd/5510: #0: ffffffff8fcd5c48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fcd5c48 (rtnl_mutex){+.+.}-{4:4}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6923 2 locks held by getty/5595: #0: ffff88814dadd0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90002fde2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211 5 locks held by syz.6.185/7341: 6 locks held by kworker/u8:10/8018: #0: ffff88801baeb148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline] #0: ffff88801baeb148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310 #1: ffffc90003a1fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc90003a1fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310 #2: ffffffff8fcc9110 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0x16a/0xcc0 net/core/net_namespace.c:586 #3: ffff88805be3e0e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1014 [inline] #3: ffff88805be3e0e8 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:108 [inline] #3: ffff88805be3e0e8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x13b/0x440 net/devlink/core.c:506 #4: ffff88805be3b250 (&devlink->lock_key#9){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:276 [inline] #4: ffff88805be3b250 (&devlink->lock_key#9){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:109 [inline] #4: ffff88805be3b250 (&devlink->lock_key#9){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x14d/0x440 net/devlink/core.c:506 #5: ffffffff8fcd5c48 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0x71/0x5c0 drivers/net/netdevsim/netdev.c:816 7 locks held by syz-executor/8958: #0: ffff88803667a420 (sb_writers#8){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2964 [inline] #0: ffff88803667a420 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x225/0xd30 fs/read_write.c:675 #1: ffff888033882c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1ea/0x500 fs/kernfs/file.c:325 #2: ffff88802798c968 (kn->active#49){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x20e/0x500 fs/kernfs/file.c:326 #3: ffffffff8f5728c8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xfc/0x480 drivers/net/netdevsim/bus.c:216 #4: ffff8880270260e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1014 [inline] #4: ffff8880270260e8 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1095 [inline] #4: ffff8880270260e8 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xce/0x7c0 drivers/base/dd.c:1293 #5: ffff888027027250 (&devlink->lock_key#14){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x160 drivers/net/netdevsim/dev.c:1675 #6: ffffffff8fcd5c48 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0x71/0x5c0 drivers/net/netdevsim/netdev.c:816 1 lock held by syz-executor/8972: #0: ffffffff8fcd5c48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #0: ffffffff8fcd5c48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:326 [inline] #0: ffffffff8fcd5c48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xd04/0x24f0 net/core/rtnetlink.c:4006 3 locks held by syz-executor/9091: #0: ffffffff8f46c480 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8f46c480 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8f46c480 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x22/0x250 net/core/rtnetlink.c:555 #1: ffffffff8fcd5c48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:79 [inline] #1: ffffffff8fcd5c48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:326 [inline] #1: ffffffff8fcd5c48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xd04/0x24f0 net/core/rtnetlink.c:4006 #2: ffffffff8e941af8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:329 [inline] #2: ffffffff8e941af8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x451/0x830 kernel/rcu/tree_exp.h:976 1 lock held by syz.0.425/9179: #0: ffffffff8e941af8 ( rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:297 [inline] rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x381/0x830 kernel/rcu/tree_exp.h:976 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.12.0-syzkaller-10689-g7af08b57bcb9 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:234 [inline] watchdog+0xff6/0x1040 kernel/hung_task.c:397 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 35 Comm: kworker/u8:2 Not tainted 6.12.0-syzkaller-10689-g7af08b57bcb9 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:memset_orig+0x46/0xb0 arch/x86/lib/memset_64.S:72 Code: 41 83 e1 07 75 70 48 89 d1 48 c1 e9 06 74 35 0f 1f 44 00 00 48 ff c9 48 89 07 48 89 47 08 48 89 47 10 48 89 47 18 48 89 47 20 <48> 89 47 28 48 89 47 30 48 89 47 38 48 8d 7f 40 75 d8 0f 1f 84 00 RSP: 0018:ffffc90000ab7958 EFLAGS: 00000202 RAX: 0000000000000000 RBX: ffff8880244a6000 RCX: 000000000000002c RDX: 0000000000001000 RSI: 0000000000000000 RDI: ffff8880244a64c0 RBP: 0000000000000000 R08: ffffffff942ee97f R09: 0000000000000000 R10: ffff8880244a6000 R11: fffffbfff285dd30 R12: 0000000000001000 R13: 0000000000082820 R14: 0000000000001000 R15: ffff88801ac42140 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005555870a95c8 CR3: 000000000e738000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: slab_post_alloc_hook mm/slub.c:4107 [inline] slab_alloc_node mm/slub.c:4153 [inline] __do_kmalloc_node mm/slub.c:4282 [inline] __kmalloc_node_track_caller_noprof+0x25b/0x4c0 mm/slub.c:4302 kmalloc_reserve+0x111/0x2a0 net/core/skbuff.c:609 __alloc_skb+0x1f3/0x440 net/core/skbuff.c:678 alloc_skb include/linux/skbuff.h:1323 [inline] nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:748 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline] nsim_dev_trap_report_work+0x261/0xb50 drivers/net/netdevsim/dev.c:851 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244