syzbot

RBP: 00007faa08701c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007faa0890f038 R14: 00007faa0890efa0 R15: 00007ffc51023098
 </TASK>
watchdog: BUG: soft lockup - CPU#1 stuck for 287s! [syz.5.1939:6811]
Modules linked in:
CPU: 1 PID: 6811 Comm: syz.5.1939 Tainted: G        W         syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:qdisc_dev include/net/sch_generic.h:596 [inline]
RIP: 0010:qdisc_match_from_root net/sched/sch_api.c:263 [inline]
RIP: 0010:qdisc_lookup+0x2a0/0x4e0 net/sched/sch_api.c:309
Code: 36 4d 8d 7e 40 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 df 7a ce fd 4d 8b 3f 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 <74> 08 4c 89 ff e8 c6 7a ce fd 4d 8b 27 4d 85 e4 74 6c 4d 8d 7e 10
RSP: 0018:ffffc90000ae6ec8 EFLAGS: 00000246
RAX: 1ffff110250f9200 RBX: 00000000ffff0000 RCX: ffff88810dd60000
RDX: 0000000000000000 RSI: 00000000ffff0000 RDI: 0000000000020000
RBP: ffffc90000ae6ef8 R08: ffff88810dd60000 R09: 0000000000000002
R10: 00000000ffffffff R11: 0000000000000000 R12: 0000000000020000
R13: dffffc0000000000 R14: ffff8881287c9800 R15: ffff8881287c9000
FS:  00007faa070f06c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000012c0 CR3: 000000012a335000 CR4: 00000000003506a0
Call Trace:
 <TASK>
 qdisc_tree_reduce_backlog+0x111/0x340 net/sched/sch_api.c:784
 fq_change+0xc5d/0x1250 net/sched/sch_fq.c:915
 fq_init+0x3e3/0x5d0 net/sched/sch_fq.c:963
 qdisc_create+0x803/0x11b0 net/sched/sch_api.c:1256
 tc_modify_qdisc+0x8ad/0x1570 net/sched/sch_api.c:-1
 rtnetlink_rcv_msg+0xa4b/0xce0 net/core/rtnetlink.c:5650
 netlink_rcv_skb+0x1f5/0x440 net/netlink/af_netlink.c:2511
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5668
 netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline]
 netlink_unicast+0x876/0xa40 net/netlink/af_netlink.c:1348
 netlink_sendmsg+0x879/0xb80 net/netlink/af_netlink.c:1922
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 ____sys_sendmsg+0x5b7/0x8f0 net/socket.c:2435
 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2489
 __sys_sendmsg net/socket.c:2518 [inline]
 __do_sys_sendmsg net/socket.c:2527 [inline]
 __se_sys_sendmsg net/socket.c:2525 [inline]
 __x64_sys_sendmsg+0x206/0x2f0 net/socket.c:2525
 x64_sys_call+0x4b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7faa08693eb9
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:00007faa070f0028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007faa0890efa0 RCX: 00007faa08693eb9
RDX: 0000000000000000 RSI: 00002000000012c0 RDI: 0000000000000007
RBP: 00007faa08701c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007faa0890f038 R14: 00007faa0890efa0 R15: 00007ffc51023098
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 0 skipped: idling at default_idle+0xf/0x20 arch/x86/kernel/process.c:729