watchdog: BUG: soft lockup - CPU#0 stuck for 123s! [syz.2.1898:7646]
Modules linked in:
CPU: 0 PID: 7646 Comm: syz.2.1898 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:qdisc_tree_reduce_backlog+0x3e/0x340 net/sched/sch_api.c:774
Code: 89 f3 49 89 ff 49 be 00 00 00 00 00 fc ff df e8 a8 6d b8 fd 31 c0 85 db 89 5d c8 0f 4f c3 89 45 cc e8 46 8d a6 fd 49 8d 5f 3c <48> 89 d8 48 c1 e8 03 42 0f b6 04 30 84 c0 0f 85 10 02 00 00 44 8b
RSP: 0018:ffffc90001896f28 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff8881170ca43c RCX: ffff8881177c93c0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8881170ca4c8
RBP: ffffc90001896f70 R08: ffff8881177c93c0 R09: 0000000000000002
R10: 00000000ffffffff R11: 0000000000000000 R12: 00000000fffffff1
R13: ffff8881170ca4cc R14: dffffc0000000000 R15: ffff8881170ca400
FS:  00007f2ed35ef6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000100000001 CR3: 000000011634a000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 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: 0033:0x7f2ed4b87749
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:00007f2ed35ef038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f2ed4dddfa0 RCX: 00007f2ed4b87749
RDX: 0000000000000000 RSI: 0000200000001200 RDI: 0000000000000005
RBP: 00007f2ed4c0bf91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2ed4dde038 R14: 00007f2ed4dddfa0 R15: 00007ffd2b0ef038
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