INFO: task syz.0.76:6580 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.76 state:D stack:26864 pid:6580 tgid:6[ 318.562284][ T39] task:syz.0.76 state:D stack:26864 pid:6580 tgid:6556 ppid:5800 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0x1472/0x4fe0 kernel/sched/core.c:6867 __schedule_loop kernel/sched/core.c:6949 [inline] schedule+0x164/0x360 kernel/sched/core.c:6964 io_schedule+0x80/0xe0 kernel/sched/core.c:7791 folio_wait_bit_common+0x6dd/0xbc0 mm/filemap.c:1323 folio_lock include/linux/pagemap.h:1170 [inline] release_metapage+0x103/0xab0 fs/jfs/jfs_metapage.c:870 discard_metapage fs/jfs/jfs_metapage.h:88 [inline] __get_metapage+0x9a3/0xde0 fs/jfs/jfs_metapage.c:753 dtSearch+0x591/0x21b0 fs/jfs/jfs_dtree.c:624 jfs_lookup+0x1b0/0x420 fs/jfs/namei.c:1461 lookup_open fs/namei.c:4422 [inline] open_last_lookups fs/namei.c:4549 [inline] path_openat+0x13db/0x3e70 fs/namei.c:4793 do_filp_open+0x22d/0x490 fs/namei.c:4823 do_sys_openat2+0x12f/0x220 fs/open.c:1430 do_sys_open fs/open.c:1436 [inline] __do_sys_creat fs/open.c:1514 [inline] __se_sys_creat fs/open.c:1508 [inline] __x64_sys_creat+0x8f/0xc0 fs/open.c:1508 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f84a732aeb9 RSP: 002b:00007f84a5565028 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 00007f84a75a6090 RCX: 00007f84a732aeb9 RDX: 0000000000000000 RSI: 000000000000006a RDI: 00002000000003c0 RBP: 00007f84a7398c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f84a75a6128 R14: 00007f84a75a6090 R15: 00007ffe58916288 Showing all locks held in the system: 2 locks held by pr/legacy/17: 1 lock held by khungtaskd/39: #0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 7 locks held by kworker/u8:3/58: #0: ffff88801aad4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88801aad4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340 #1: ffffc9000124fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc9000124fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340 #2: ffffffff8ef2caa0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xfe/0x7b0 net/core/net_namespace.c:670 #3: ffff8880360f00d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #3: ffff8880360f00d8 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:108 [inline] #3: ffff8880360f00d8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x117/0x3f0 net/devlink/core.c:506 #4: ffff88803adfa300 (&devlink->lock_key#11){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:276 [inline] #4: ffff88803adfa300 (&devlink->lock_key#11){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:109 [inline] #4: ffff88803adfa300 (&devlink->lock_key#11){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x129/0x3f0 net/devlink/core.c:506 #5: ffffffff8ef3b3b8 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0xed/0x680 drivers/net/netdevsim/netdev.c:1175 #6: ffff888036ea8e98 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2781 [inline] #6: ffff888036ea8e98 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline] #6: ffff888036ea8e98 (&dev_instance_lock_key#24){+.+.}-{4:4}, at: unregister_netdevice_many_notify+0x118e/0x2360 net/core/dev.c:12383 3 locks held by kworker/u8:6/1018: #0: ffff88814d52b138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88814d52b138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340 #1: ffffc9000465fbc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc9000465fbc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340 #2: ffffffff8ef3b3b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8ef3b3b8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x124/0x1680 net/ipv6/addrconf.c:4194 1 lock held by dhcpcd/5459: #0: ffffffff8ef3b3b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8ef3b3b8 (rtnl_mutex){+.+.}-{4:4}, at: devinet_ioctl+0x32b/0x1b30 net/ipv4/devinet.c:1120 2 locks held by getty/5549: #0: ffff88814e5150a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211 1 lock held by udevd/5806: #0: ffff8881427484c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xcc0 block/bdev.c:962 1 lock held by syz.0.76/6580: #0: ffff88805ecd85b8 (&type->i_mutex_dir_key#17){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline] #0: ffff88805ecd85b8 (&type->i_mutex_dir_key#17){+.+.}-{4:4}, at: open_last_lookups fs/namei.c:4546 [inline] #0: ffff88805ecd85b8 (&type->i_mutex_dir_key#17){+.+.}-{4:4}, at: path_openat+0xb65/0x3e70 fs/namei.c:4793 7 locks held by syz-executor/8303: #0: ffff8880355b8480 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2683 [inline] #0: ffff8880355b8480 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22d/0xba0 fs/read_write.c:682 #1: ffff88803bf8cc78 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1df/0x540 fs/kernfs/file.c:343 #2: ffff8880276ac008 (kn->active#53){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff8880276ac008 (kn->active#53){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x232/0x540 fs/kernfs/file.c:344 #3: ffffffff8e7aa818 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: new_device_store+0x13c/0x710 drivers/net/netdevsim/bus.c:184 #4: ffff8880361dd0d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #4: ffff8880361dd0d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1008 #5: ffff8880332b8300 (&devlink->lock_key#12){+.+.}-{4:4}, at: nsim_drv_probe+0xc9/0xc30 drivers/net/netdevsim/dev.c:1637 #6: ffffffff8ef3b3b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #6: ffffffff8ef3b3b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_dev_lock+0x257/0x2f0 net/core/dev.c:2156 2 locks held by syz-executor/8546: #0: ffffffff8f480670 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8f480670 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8f480670 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8ef3b3b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8ef3b3b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8ef3b3b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4071 2 locks held by syz.1.281/8631: 2 locks held by syz.7.283/8670: 1 lock held by syz.4.282/8678: #0: ffff8881427484c8 (&disk->open_mutex){+.+.}-{4:4}, at: loop_reread_partitions drivers/block/loop.c:447 [inline] #0: ffff8881427484c8 (&disk->open_mutex){+.+.}-{4:4}, at: loop_set_status+0x851/0xed0 drivers/block/loop.c:1293 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 39 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 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+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline] watchdog+0xf90/0xfe0 kernel/hung_task.c:515 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 1189 Comm: irq/33-virtio1- Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 RIP: 0010:check_preemption_disabled+0x3/0xe0 lib/smp_processor_id.c:13 Code: 85 8b 48 c7 c6 60 e8 85 8b eb 1c 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 <41> 56 53 65 8b 05 b7 f6 17 07 65 8b 0d ac f6 17 07 f7 c1 ff ff ff RSP: 0018:ffffc90004c6eea0 EFLAGS: 00000282 RAX: 0000000000000001 RBX: ffffffff82276a2c RCX: ffff8880271cbc80 RDX: 00000000f1008011 RSI: ffffffff8b85e860 RDI: ffffffff8b85e820 RBP: dffffc0000000000 R08: ffffffff81757165 R09: ffffffff8dbc77c0 R10: ffffc90004c6eff8 R11: ffffffff81ae5ef0 R12: 1ffff9200098ddf5 R13: ffffc90004c6efe0 R14: ffffc90004c6efa8 R15: ffffffff81757165 FS: 0000000000000000(0000) GS:ffff8881266c9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5603e66e9c CR3: 0000000058152000 CR4: 00000000003526f0 Call Trace: rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline] rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:751 rcu_read_lock include/linux/rcupdate.h:868 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xd4/0x23c0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] kmem_cache_alloc_bulk_noprof+0x490/0x770 mm/slub.c:7525 napi_skb_cache_get+0x263/0x410 net/core/skbuff.c:291 __alloc_skb+0x152/0x390 net/core/skbuff.c:668 napi_alloc_skb+0x9a/0x440 net/core/skbuff.c:832 page_to_skb+0x2ce/0x870 drivers/net/virtio_net.c:887 receive_mergeable drivers/net/virtio_net.c:2497 [inline] receive_buf+0x546/0x1900 drivers/net/virtio_net.c:2643 virtnet_receive_packets drivers/net/virtio_net.c:2970 [inline] virtnet_receive drivers/net/virtio_net.c:2994 [inline] virtnet_poll+0x21ed/0x2fd0 drivers/net/virtio_net.c:3083 __napi_poll+0xae/0x530 net/core/dev.c:7681 napi_poll net/core/dev.c:7744 [inline] net_rx_action+0x696/0xe00 net/core/dev.c:7896 handle_softirqs+0x1de/0x640 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] __local_bh_enable_ip+0x170/0x2b0 kernel/softirq.c:302 local_bh_enable include/linux/bottom_half.h:33 [inline] irq_forced_thread_fn+0xe9/0x120 kernel/irq/manage.c:1147 irq_thread+0x4c9/0x740 kernel/irq/manage.c:1250 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246