INFO: task syz.1.323:9182 blocked for more than 143 seconds. Not tainted 6.15.0-syzkaller-08297-ge0797d3b91de #0 Blocked by coredump. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.323 state:D stack:25224 pid:9182 tgid:9133 ppid:5819 task_flags:0x40044c flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5392 [inline] __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6781 __schedule_loop kernel/sched/core.c:6859 [inline] schedule+0x165/0x360 kernel/sched/core.c:6874 request_wait_answer fs/fuse/dev.c:564 [inline] __fuse_request_send fs/fuse/dev.c:578 [inline] __fuse_simple_request+0xf12/0x18d0 fs/fuse/dev.c:672 fuse_simple_request fs/fuse/fuse_i.h:1237 [inline] fuse_flush+0x5bc/0x860 fs/fuse/file.c:557 filp_flush+0xbd/0x190 fs/open.c:1549 filp_close+0x1d/0x40 fs/open.c:1562 close_files fs/file.c:479 [inline] put_files_struct+0x1ba/0x350 fs/file.c:494 do_exit+0x88b/0x2550 kernel/exit.c:954 do_group_exit+0x21c/0x2d0 kernel/exit.c:1108 get_signal+0x125e/0x1310 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:111 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline] do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1b5db8d41f RSP: 002b:00007f1b5ea2fdf0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: 000000000092d000 RBX: 0000000001000000 RCX: 00007f1b5db8d41f RDX: 0000000001000000 RSI: 00007f1b52c00000 RDI: 0000000000000009 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000009687 R10: 000020000001c302 R11: 0000000000000293 R12: 0000000000000009 R13: 00007f1b5ea2fef0 R14: 00007f1b5ea2feb0 R15: 00007f1b52c00000 Showing all locks held in the system: 3 locks held by kworker/u8:0/12: #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc90000117bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc90000117bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 #2: ffffffff8f4f8888 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303 1 lock held by khungtaskd/31: #0: ffffffff8e13ccc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e13ccc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e13ccc0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770 3 locks held by kworker/u8:6/3467: #0: ffff88814c48b148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88814c48b148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc9000c3f7bc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9000c3f7bc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 #2: ffffffff8f4f8888 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8f4f8888 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x112/0x14b0 net/ipv6/addrconf.c:4198 5 locks held by kworker/u8:8/3537: #0: ffff88801b2fb948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801b2fb948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc9000c537bc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9000c537bc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 #2: ffffffff8f4ebc90 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x8a0 net/core/net_namespace.c:662 #3: ffffffff8f4f8888 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0xdc/0x890 net/core/dev.c:12629 #4: ffffffff8e1427f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:304 [inline] #4: ffffffff8e1427f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f4/0x730 kernel/rcu/tree_exp.h:998 2 locks held by getty/5582: #0: ffff888034f320a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 1 lock held by syz-executor/10545: 2 locks held by syz-executor/10700: #0: ffffffff8f55e9f0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8f4f8888 (rtnl_mutex){+.+.}-{4:4}, at: nl80211_pre_doit+0x5f/0x930 net/wireless/nl80211.c:16733 1 lock held by syz-executor/10998: #0: ffffffff8f4f8888 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f4f8888 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:979 2 locks held by syz-executor/11201: #0: ffffffff8f9fd530 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8f9fd530 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8f9fd530 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8f4f8888 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8f4f8888 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8f4f8888 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4054 1 lock held by udevadm/11307: 2 locks held by syz.5.517/11312: #0: ffff888142b0f358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1a9/0x650 block/bdev.c:1128 #1: ffff8880b863b858 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:606 1 lock held by cmp/11314: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-syzkaller-08297-ge0797d3b91de #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 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:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline] watchdog+0xfee/0x1030 kernel/hung_task.c:437 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 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: 64 Comm: kworker/u8:4 Not tainted 6.15.0-syzkaller-08297-ge0797d3b91de #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: writeback wb_workfn (flush-8:0) RIP: 0010:blk_mq_rq_ctx_init+0xbe/0x580 block/blk-mq.c:407 Code: be 86 fd 44 89 7c 24 0c 45 89 ff 49 c1 e7 03 4c 03 3b 4c 89 f8 48 c1 e8 03 80 3c 28 00 74 08 4c 89 ff e8 b5 be 86 fd 49 8b 1f <48> 89 d8 48 c1 e8 03 80 3c 28 00 74 08 48 89 df e8 8d bf 86 fd 4c RSP: 0018:ffffc9000210e690 EFLAGS: 00000246 RAX: 1ffff110051434d2 RBX: ffff888028ade000 RCX: ffff88801abb9e00 RDX: 0000000000000000 RSI: ffff888028915000 RDI: ffffc9000210e910 RBP: dffffc0000000000 R08: ffff888025d85057 R09: 1ffff11004bb0a0a R10: dffffc0000000000 R11: ffffed1004bb0a0b R12: ffff8880256430e8 R13: ffffe8ffffd0fdc0 R14: ffffc9000210e8e0 R15: ffff888028a1a690 FS: 0000000000000000(0000) GS:ffff888125d98000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007faef66af68c CR3: 000000007e5ec000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __blk_mq_alloc_requests+0xf7f/0x11f0 block/blk-mq.c:564 blk_mq_get_new_requests block/blk-mq.c:3039 [inline] blk_mq_submit_bio+0x733/0x22d0 block/blk-mq.c:3179 __submit_bio+0x207/0x5a0 block/blk-core.c:635 __submit_bio_noacct_mq block/blk-core.c:722 [inline] submit_bio_noacct_nocheck+0x4ab/0xb50 block/blk-core.c:751 ext4_io_submit+0xe0/0x150 fs/ext4/page-io.c:404 ext4_do_writepages+0x12d8/0x3f30 fs/ext4/inode.c:2883 ext4_writepages+0x205/0x350 fs/ext4/inode.c:2953 do_writepages+0x32b/0x550 mm/page-writeback.c:2635 __writeback_single_inode+0x145/0xff0 fs/fs-writeback.c:1680 writeback_sb_inodes+0x6b5/0x1000 fs/fs-writeback.c:1976 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2047 wb_writeback+0x44f/0xaf0 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+0xaef/0xef0 fs/fs-writeback.c:2343 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245