watchdog: BUG: soft lockup - CPU#0 stuck for 123s! [syz.4.7317:28258] Modules linked in: CPU: 0 PID: 28258 Comm: syz.4.7317 Tainted: G W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x82/0x90 kernel/kcov.c:286 Code: 8d 50 28 4d 39 ca 77 22 89 ff 89 f6 4a c7 44 01 08 05 00 00 00 4a 89 7c 01 10 4a 89 74 01 18 4a 89 44 01 20 48 ff c2 48 89 11 <5d> c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 55 48 89 e5 48 8b 45 08 RSP: 0018:ffffc9000105ef18 EFLAGS: 00000297 RAX: ffffffff83ab374d RBX: 0000000000000022 RCX: 0000000000000002 RDX: ffff8881108562c0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000105ef18 R08: ffff8881108562c0 R09: 0000000000000002 R10: 00000000ffffffff R11: 0000000000000002 R12: 00000000fffffff1 R13: ffff888120691ccc R14: dffffc0000000000 R15: ffff888120691c00 FS: 00007f0d0b27b6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0d0b27af98 CR3: 00000001156fd000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: qdisc_tree_reduce_backlog+0x9d/0x340 net/sched/sch_api.c:778 fq_change+0xb9e/0x10a0 net/sched/sch_fq.c:915 fq_init+0x3e3/0x5d0 net/sched/sch_fq.c:963 qdisc_create+0x780/0x1040 net/sched/sch_api.c:1255 tc_modify_qdisc+0x8da/0x14c0 net/sched/sch_api.c:1715 rtnetlink_rcv_msg+0x9db/0xb90 net/core/rtnetlink.c:5610 netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2503 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5628 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x876/0xa40 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x88d/0xb30 net/netlink/af_netlink.c:1914 sock_sendmsg_nosec net/socket.c:652 [inline] __sock_sendmsg net/socket.c:664 [inline] ____sys_sendmsg+0x5a2/0x8c0 net/socket.c:2376 ___sys_sendmsg+0x1f0/0x260 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+0x1e2/0x2a0 net/socket.c:2466 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f0d0c834749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f0d0b27b038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f0d0ca8b090 RCX: 00007f0d0c834749 RDX: 0000000000000000 RSI: 0000200000001200 RDI: 0000000000000005 RBP: 00007f0d0c8b8f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0d0ca8b128 R14: 00007f0d0ca8b090 R15: 00007fffd754fc78 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:60 [inline] NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:103 [inline] NMI backtrace for cpu 1 skipped: idling at default_idle+0x12/0x20 arch/x86/kernel/process.c:717