INFO: tas[ 828.672639][ T39] INFO: task syz.0.578:12154 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.578 state:D stack:25592 pid:12154 tgid:12153 ppid:5605 task_flags:0x400140 flags:0x00080003 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x16ec/0x5620 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 schedule_timeout+0xc3/0x2c0 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:100 [inline] __wait_for_common kernel/sched/completion.c:121 [inline] wait_for_common kernel/sched/completion.c:132 [inline] wait_for_completion+0x2cc/0x5e0 kernel/sched/completion.c:153 kthread_flush_worker+0x138/0x1a0 kernel/kthread.c:1579 __alloc_workqueue+0x15f5/0x1f40 kernel/workqueue.c:5909 alloc_workqueue_va kernel/workqueue.c:5931 [inline] alloc_workqueue_noprof+0xe3/0x210 kernel/workqueue.c:5947 btrfs_init_workqueues+0x3de/0x680 fs/btrfs/disk-io.c:1968 open_ctree+0x1598/0x4190 fs/btrfs/disk-io.c:3444 btrfs_fill_super fs/btrfs/super.c:981 [inline] btrfs_get_tree_super fs/btrfs/super.c:1944 [inline] btrfs_get_tree_subvol fs/btrfs/super.c:2087 [inline] btrfs_get_tree+0x1061/0x1910 fs/btrfs/super.c:2121 vfs_get_tree+0x92/0x2a0 fs/super.c:1754 fc_mount fs/namespace.c:1193 [inline] do_new_mount_fc fs/namespace.c:3758 [inline] do_new_mount+0x341/0xd30 fs/namespace.c:3834 do_mount fs/namespace.c:4167 [inline] __do_sys_mount fs/namespace.c:4383 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4360 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0x560 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb17c95e0ca RSP: 002b:00007fb17abade58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fb17abadee0 RCX: 00007fb17c95e0ca RDX: 0000200000005100 RSI: 0000200000000040 RDI: 00007fb17abadea0 RBP: 0000200000005100 R08: 00007fb17abadee0 R09: 0000000000800810 R10: 0000000000800810 R11: 0000000000000246 R12: 0000200000000040 R13: 00007fb17abadea0 R14: 000000000000510a R15: 0000200000000140 Showing all locks held in the system: 2 locks held by rcuc/1/28: 1 lock held by khungtaskd/39: #0: ffffffff8dfc80c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8dfc80c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8dfc80c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by kworker/u8:16/3326: #0: ffff88801a074938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff88801a074938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397 #1: ffffc9000e53fc40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline] #1: ffffc9000e53fc40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397 7 locks held by kworker/u8:21/3456: 2 locks held by getty/5361: #0: ffff8880372930a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003cc62e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13a0 drivers/tty/n_tty.c:2211 9 locks held by syz-executor/5608: 1 lock held by udevd/5922: #0: ffff888037d84480 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 1 lock held by udevd/8516: #0: ffff888037d84480 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 1 lock held by syz.0.578/12154: #0: ffff888038bf20d0 (&type->s_umount_key#56/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xac0 fs/super.c:345 3 locks held by kworker/u8:10/13144: #0: ffff88801b290938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline] #0: ffff88801b290938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397 #1: ffffc90012aa7c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline] #1: ffffc90012aa7c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397 #2: ffffffff8dfce270 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828 2 locks held by syz-executor/13273: 2 locks held by syz-executor/13277: #0: ffffffff8f8af318 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8f8af318 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8f8af318 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8f358e78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8f358e78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8f358e78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x883/0x1bb0 net/core/rtnetlink.c:4109 7 locks held by syz.1.744/13527: 1 lock held by rm/13531: 1 lock held by modprobe/13532: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 39 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 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:162 [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:353 [inline] watchdog+0xfd3/0x1030 kernel/hung_task.c:561 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 8516 Comm: udevd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:__lock_acquire+0x99/0x2cf0 kernel/locking/lockdep.c:5111 Code: c8 89 4c 24 10 8b 0d b6 1a d6 17 85 c9 0f 95 c0 83 fe 08 0f 92 c2 08 c2 0f 84 49 01 00 00 83 fe 01 77 0c 89 f0 49 8b 44 c1 08 <48> 85 c0 75 21 31 ed 4c 89 cf 31 d2 4c 89 cb e8 03 f1 ff ff 48 85 RSP: 0018:ffffc9001d667900 EFLAGS: 00000097 RAX: ffffffff9313f5f8 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff8880b8844538 RBP: 0000000000000000 R08: 0000000000000001 R09: ffff8880b8844538 R10: dffffc0000000000 R11: fffffbfff1f1225f R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000 FS: 00007f8a64b66880(0000) GS:ffff888126170000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1aa0425000 CR3: 00000000600fe000 CR4: 00000000003526f0 Call Trace: lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 __rt_spin_trylock kernel/locking/spinlock_rt.c:109 [inline] rt_spin_trylock+0xfc/0x2b0 kernel/locking/spinlock_rt.c:118 alloc_from_pcs mm/slub.c:4744 [inline] slab_alloc_node mm/slub.c:4884 [inline] kmem_cache_alloc_lru_noprof+0x1a8/0x680 mm/slub.c:4918 shmem_alloc_inode+0x28/0x40 mm/shmem.c:5159 alloc_inode+0x6a/0x1b0 fs/inode.c:345 new_inode+0x22/0x170 fs/inode.c:1179 __shmem_get_inode mm/shmem.c:3076 [inline] shmem_get_inode+0x3da/0xf70 mm/shmem.c:3150 shmem_symlink+0xa3/0x470 mm/shmem.c:4093 vfs_symlink+0x195/0x340 fs/namei.c:5643 filename_symlinkat+0x1cd/0x420 fs/namei.c:5668 __do_sys_symlink fs/namei.c:5695 [inline] __se_sys_symlink+0x4d/0x2b0 fs/namei.c:5691 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0x560 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8a64cc2527 Code: f0 ff ff 77 06 c3 0f 1f 44 00 00 48 8b 15 c9 b8 0d 00 f7 d8 64 89 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 b8 58 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 a1 b8 0d 00 f7 d8 64 89 02 b8 RSP: 002b:00007ffd93419788 EFLAGS: 00000202 ORIG_RAX: 0000000000000058 RAX: ffffffffffffffda RBX: 000055fd2a49a9a0 RCX: 00007f8a64cc2527 RDX: fffffffffffffe68 RSI: 00007ffd93419790 RDI: 000055fd2a429350 RBP: 0000000000000c78 R08: 0000000000000064 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffd93419790 R13: 000055fd2a42c190 R14: 0000000000000008 R15: 000055fd2a49a9a0