watchdog: BUG: soft lockup - CPU#0 stuck for 123s! [syz.2.17:487]
Modules linked in:
CPU: 0 PID: 487 Comm: syz.2.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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 c0 b9 9d 7e 65 8b
RSP: 0018:ffffc900021e6ed8 EFLAGS: 00000293
RAX: ffffffff83b28035 RBX: 00000000ffff0000 RCX: ffff8881178ce2c0
RDX: 0000000000000000 RSI: 00000000ffff0000 RDI: 0000000000000000
RBP: ffffc900021e6ed8 R08: ffff8881178ce2c0 R09: 0000000000000002
R10: 00000000ffffffff R11: 0000000000000000 R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffffffffffd8 R15: ffff8881179d4000
FS:  00007ff9285e26c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001200 CR3: 0000000114cdd000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 qdisc_match_from_root net/sched/sch_api.c:270 [inline]
 qdisc_lookup+0x1a5/0x4e0 net/sched/sch_api.c:304
 qdisc_tree_reduce_backlog+0x111/0x340 net/sched/sch_api.c:783
 fq_change+0xbdb/0x1100 net/sched/sch_fq.c:915
 fq_init+0x3e3/0x5d0 net/sched/sch_fq.c:963
 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:5610
 netlink_rcv_skb+0x1f5/0x440 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+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: 0033:0x7ff92877d379
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:00007ff9285e2028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ff9289c8fa0 RCX: 00007ff92877d379
RDX: 0000000000000010 RSI: 0000200000001200 RDI: 0000000000000006
RBP: 00007ff928810d68 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff9289c9038 R14: 00007ff9289c8fa0 R15: 00007ffc4b2a88e8
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