watchdog: BUG: soft lockup - CPU#1 stuck for 123s! [syz.1.347:1766] Modules linked in: CPU: 1 PID: 1766 Comm: syz.1.347 Tainted: G W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:qdisc_tree_reduce_backlog+0x87/0x340 net/sched/sch_api.c:778 Code: af 86 e8 bc e6 b1 fd 4d 85 e4 0f 84 a2 02 00 00 41 83 fc ff 0f 84 91 02 00 00 49 8d 5f 10 48 89 d8 48 c1 e8 03 42 0f b6 04 30 <84> c0 0f 85 f0 01 00 00 8b 1b 89 de 83 e6 40 31 ff e8 73 e5 b1 fd RSP: 0018:ffffc90000b86f48 EFLAGS: 00000a02 RAX: 0000000000000000 RBX: ffff888110199010 RCX: 0000000000000005 RDX: ffffffff83b2e694 RSI: ffffffff86af4120 RDI: 00000000fffffff1 RBP: ffffc90000b86f90 R08: ffff88811648a780 R09: 0000000000000002 R10: 00000000ffffffff R11: 0000000000000002 R12: 00000000fffffff1 R13: ffff8881101990cc R14: dffffc0000000000 R15: ffff888110199000 FS: 00007fbdf8add6c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000132b2c000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: codel_change+0x8fc/0xbe0 net/sched/sch_codel.c:180 codel_init+0x1a8/0x390 net/sched/sch_codel.c:199 qdisc_create+0x848/0x1220 net/sched/sch_api.c:1255 tc_modify_qdisc+0x8a1/0x1490 net/sched/sch_api.c:-1 rtnetlink_rcv_msg+0xa31/0xcc0 net/core/rtnetlink.c:5613 netlink_rcv_skb+0x1f5/0x440 net/netlink/af_netlink.c:2503 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5631 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x876/0xa40 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x89c/0xb50 net/netlink/af_netlink.c:1914 sock_sendmsg_nosec net/socket.c:652 [inline] __sock_sendmsg net/socket.c:664 [inline] ____sys_sendmsg+0x5b7/0x8f0 net/socket.c:2376 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2430 __sys_sendmsg net/socket.c:2459 [inline] __do_sys_sendmsg net/socket.c:2468 [inline] __se_sys_sendmsg net/socket.c:2466 [inline] __x64_sys_sendmsg+0x1f9/0x2c0 net/socket.c:2466 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7fbdfa0a3e59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fbdf8add028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fbdfa31d090 RCX: 00007fbdfa0a3e59 RDX: 0000000000000000 RSI: 0000200000001200 RDI: 0000000000000003 RBP: 00007fbdfa139d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fbdfa31d128 R14: 00007fbdfa31d090 R15: 00007ffce9f705b8 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:__sanitizer_cov_trace_pc+0x5c/0x60 kernel/kcov.c:207 Code: b8 0a 00 00 83 fa 02 75 21 48 8b 91 c0 0a 00 00 48 8b 32 48 8d 7e 01 8b 89 bc 0a 00 00 48 39 cf 73 08 48 89 44 f2 08 48 89 3a <5d> c3 66 90 55 48 89 e5 48 8b 45 08 65 48 8b 15 80 a4 9d 7e 65 8b RSP: 0018:ffffc90000007cd8 EFLAGS: 00000046 RAX: ffffffff823dc3ac RBX: 00000000000000c0 RCX: ffffffff8641c100 RDX: 0000000000000102 RSI: 00000000000000c0 RDI: ffff8881f70488e8 RBP: ffffc90000007cd8 R08: ffff8881f70488ef R09: 1ffff1103ee0911d R10: dffffc0000000000 R11: ffffed103ee0911e R12: 000000000400000e R13: ffff8881f70488e8 R14: 000000000000008e R15: ffff8881f70488e8 FS: 0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5565a3e218 CR3: 000000011c30d000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: find_next_bit+0x1c/0x100 lib/find_bit.c:78 next_pending_bucket kernel/time/timer.c:1539 [inline] __next_timer_interrupt+0x9e/0x2a0 kernel/time/timer.c:1559 __run_timers+0x413/0x9e0 kernel/time/timer.c:1786 run_timer_softirq+0xb8/0xf0 kernel/time/timer.c:1804 __do_softirq+0x255/0x563 kernel/softirq.c:309 asm_call_irq_on_stack+0xf/0x20 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline] do_softirq_own_stack+0x60/0x80 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:405 [inline] __irq_exit_rcu+0x128/0x150 kernel/softirq.c:435 irq_exit_rcu+0x9/0x10 kernel/softirq.c:447 sysvec_apic_timer_interrupt+0xbf/0xe0 arch/x86/kernel/apic/apic.c:1106 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:635 RIP: 0010:default_idle+0x12/0x20 arch/x86/kernel/process.c:718 Code: 44 2a 00 00 49 bd 00 00 00 00 00 fc ff df e9 67 ff ff ff e8 d0 f7 fa ff 55 48 89 e5 0f 1f 44 00 00 0f 00 2d b0 f6 61 00 fb f4 <5d> c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 55 48 89 e5 41 57 41 56 RSP: 0018:ffffffff86407d78 EFLAGS: 00000252 RAX: ffff8881f7000000 RBX: ffffffff8641c100 RCX: 000000000006450e RDX: 0000000000000001 RSI: ffffffff85409040 RDI: ffffffff85409000 RBP: ffffffff86407d78 R08: ffff8881f70573d3 R09: 1ffff1103ee0ae7a R10: dffffc0000000000 R11: ffffed103ee0ae7b R12: 0000000000000000 R13: 1ffffffff0c83820 R14: dffffc0000000000 R15: dffffc0000000000 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:709 default_idle_call+0x71/0x1d0 kernel/sched/idle.c:114 cpuidle_idle_call kernel/sched/idle.c:204 [inline] do_idle+0x217/0x620 kernel/sched/idle.c:328 cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:425 rest_init+0xe8/0xf0 init/main.c:728 arch_call_rest_init+0xe/0x10 init/main.c:853 start_kernel+0x431/0x49f init/main.c:1055 x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:519 x86_64_start_kernel+0x60/0x63 arch/x86/kernel/head64.c:500 secondary_startup_64_no_verify+0xad/0xbb