INFO: task kworker/u10:4:8604 blocked for more than 143 seconds. Tainted: G U 6.15.0-rc7-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u10:4 state:D stack:26952 pid:8604 tgid:8604 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: netns cleanup_net 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 schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:95 [inline] __wait_for_common+0x2fc/0x4e0 kernel/sched/completion.c:116 __flush_workqueue+0x3e2/0x1230 kernel/workqueue.c:4000 rds_tcp_listen_stop+0x104/0x150 net/rds/tcp_listen.c:351 rds_tcp_kill_sock net/rds/tcp.c:611 [inline] rds_tcp_exit_net+0xcb/0x810 net/rds/tcp.c:634 ops_exit_list+0xb0/0x180 net/core/net_namespace.c:172 cleanup_net+0x5c1/0xb30 net/core/net_namespace.c:654 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+0x48/0x80 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: 1 lock held by khungtaskd/31: #0: ffffffff8e3bfa80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e3bfa80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e3bfa80 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6764 2 locks held by getty/5601: #0: ffff8880317c10a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900030062f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 3 locks held by kworker/u10:4/8604: #0: ffff88801c2f6148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213 #1: ffffc900038cfd18 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214 #2: ffffffff90114550 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xc9/0xb30 net/core/net_namespace.c:608 1 lock held by syz.3.885/9775: #0: ffffffff90114550 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x286/0x5f0 net/core/net_namespace.c:514 1 lock held by syz.1.1103/10757: #0: ffffffff90114550 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x286/0x5f0 net/core/net_namespace.c:514 1 lock held by syz.0.1203/11197: 1 lock held by syz.2.1207/11215: #0: ffffffff90114550 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x286/0x5f0 net/core/net_namespace.c:514 4 locks held by syz.5.1220/11267: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G U 6.15.0-rc7-syzkaller #0 PREEMPT(full) Tainted: [U]=USER 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+0x48/0x80 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: 11197 Comm: syz.0.1203 Tainted: G U 6.15.0-rc7-syzkaller #0 PREEMPT(full) Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:unwind_next_frame+0x533/0x20a0 arch/x86/kernel/unwind_orc.c:512 Code: b6 04 02 4c 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 32 14 00 00 0f b6 41 05 83 e0 07 0f 84 53 fe ff ff 3c 01 0f 84 7b fe ff ff <4c> 8d 41 04 4c 89 fe 48 b8 00 00 00 00 00 fc ff df 4c 89 c2 48 c1 RSP: 0018:ffffc9000b4eefd0 EFLAGS: 00000202 RAX: 0000000000000002 RBX: 0000000000000001 RCX: ffffffff9124d38a RDX: 0000000000000007 RSI: 0000000000000000 RDI: ffffffff909e0d9c RBP: ffffc9000b4ef088 R08: ffffffff9124d390 R09: 0000000000000000 R10: 0000000000000000 R11: 000000000000fc70 R12: ffffc9000b4ef090 R13: ffffc9000b4ef040 R14: ffffc9000b4ef075 R15: ffffffff9124d38f FS: 0000000000000000(0000) GS:ffff888124ae7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f425e55e990 CR3: 0000000033388000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: 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_unref_folios+0x999/0x1630 mm/page_alloc.c:2778 folios_put_refs+0x56f/0x740 mm/swap.c:992 folio_batch_release include/linux/pagevec.h:101 [inline] shmem_undo_range+0x58f/0x1150 mm/shmem.c:1125 shmem_truncate_range mm/shmem.c:1237 [inline] shmem_evict_inode+0x3a1/0xbe0 mm/shmem.c:1365 evict+0x3e3/0x920 fs/inode.c:810 iput_final fs/inode.c:1898 [inline] iput fs/inode.c:1924 [inline] iput+0x521/0x880 fs/inode.c:1910 dentry_unlink_inode+0x29c/0x480 fs/dcache.c:457 __dentry_kill+0x1d0/0x600 fs/dcache.c:660 dput.part.0+0x4b1/0x9b0 fs/dcache.c:902 dput+0x1f/0x30 fs/dcache.c:892 __fput+0x51c/0xb70 fs/file_table.c:473 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/0x7a0 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] irqentry_exit_to_user_mode+0x13f/0x280 kernel/entry/common.c:231 asm_exc_stack_segment+0x26/0x30 arch/x86/include/asm/idtentry.h:616 RIP: 0033:0x7f6fbdd8e971 Code: Unable to access opcode bytes at 0x7f6fbdd8e947. RSP: 002b:8000000000000000 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007f6fbdfb5fa0 RCX: 00007f6fbdd8e969 RDX: 0000000000000000 RSI: 8000000000000000 RDI: 0000000020003b4b RBP: 00007f6fbde10ab1 R08: 00000000000001b0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f6fbdfb5fa0 R15: 00007fff54b11f18