INFO: task syz-executor:9287 blocked for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:18952 pid:9287 tgid:9287 ppid:1 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5504 [inline] __schedule+0x1709/0x5530 kernel/sched/core.c:7228 __schedule_loop kernel/sched/core.c:7307 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7603 rt_mutex_slowlock_block+0x55c/0x680 kernel/locking/rtmutex.c:1670 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline] __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline] rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline] __mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline] mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578 del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234 kernfs_fop_write_iter+0x3a5/0x540 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x61e/0xbb0 fs/read_write.c:687 ksys_write+0x156/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f546b58d68e RSP: 002b:00007fff34b93f78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000555578fe2500 RCX: 00007f546b58d68e RDX: 0000000000000001 RSI: 00007fff34b94000 RDI: 0000000000000005 RBP: 00007f546b6635f2 R08: 0000000000000000 R09: 0000000000000000 R13: 00007fff34b94000 R14: 00007f546c374620 R15: 0000000000000003 INFO: task syz-executor:9316 blocked for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:22088 pid:9316 tgid:9316 ppid:1 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5504 [inline] __schedule+0x1709/0x5530 kernel/sched/core.c:7228 __schedule_loop kernel/sched/core.c:7307 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7603 rt_mutex_slowlock_block+0x55c/0x680 kernel/locking/rtmutex.c:1670 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline] __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline] rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline] __mutex_lock_common kernel/locking/rtmutex_api.c:560 [inline] mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:578 del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234 kernfs_fop_write_iter+0x3a5/0x540 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x61e/0xbb0 fs/read_write.c:687 ksys_write+0x156/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc561c4d68e RSP: 002b:00007ffe4c912158 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000055556abcf500 RCX: 00007fc561c4d68e RDX: 0000000000000001 RSI: 00007ffe4c9121e0 RDI: 0000000000000005 RBP: 00007fc561d235f2 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffe4c9121e0 R14: 00007fc562a34620 R15: 0000000000000003 INFO: lockdep is turned off. NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122 nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65 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+0xfd7/0x1030 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 29 Comm: rcuc/1 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:__sanitizer_cov_trace_pc+0x6b/0x80 kernel/kcov.c:235 Code: e0 16 00 00 83 fa 02 75 21 48 8b 91 e8 16 00 00 48 8b 32 48 8d 7e 01 8b 89 e4 16 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 10 07 6f 09 cc 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 RSP: 0018:ffffc90000a3edd8 EFLAGS: 00000246 RAX: ffffffff890a5d00 RBX: 00000000000660c0 RCX: ffff88801de8be00 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000100 RBP: ffffc90000a3ef78 R08: 0000000000000000 R09: 0000000000000100 R10: ffffc90000a3ed40 R11: fffff52000147dac R12: e00000000cb7dd4b R13: e00000000cb7dd4a R14: 1ffffffff34822b4 R15: e00000000cb7dd4a FS: 0000000000000000(0000) GS:ffff888125fcb000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2c436ba368 CR3: 000000000ddb8000 CR4: 00000000003526f0 Call Trace: save_dst_trace_buffer+0x1e0/0x5b0 net/core/dst.c:104 dst_release+0x28/0x1b0 net/core/dst.c:250 refdst_drop include/net/dst.h:286 [inline] skb_dst_drop include/net/dst.h:298 [inline] skb_release_head_state+0x71/0x360 net/core/skbuff.c:1165 skb_release_all net/core/skbuff.c:1189 [inline] __kfree_skb+0x24/0x210 net/core/skbuff.c:1205 nft_synproxy_eval_v4+0x383/0x530 net/netfilter/nft_synproxy.c:61 nft_synproxy_do_eval+0x335/0x550 net/netfilter/nft_synproxy.c:142 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x48d/0x1ad0 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0x360/0x4b0 net/netfilter/nft_chain_filter.c:162 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:316 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6205 [inline] __netif_receive_skb net/core/dev.c:6318 [inline] process_backlog+0x564/0xc50 net/core/dev.c:6669 __napi_poll+0xae/0x550 net/core/dev.c:7728 napi_poll net/core/dev.c:7791 [inline] net_rx_action+0x621/0xd70 net/core/dev.c:7948 handle_softirqs+0x1d9/0x6c0 kernel/softirq.c:626 __do_softirq kernel/softirq.c:660 [inline] __local_bh_enable_ip+0x170/0x2b0 kernel/softirq.c:302 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_do_batch kernel/rcu/tree.c:2664 [inline] rcu_core kernel/rcu/tree.c:2897 [inline] rcu_cpu_kthread+0x99f/0x1480 kernel/rcu/tree.c:2985 smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160 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