=============================
WARNING: suspicious RCU usage
5.15.173-syzkaller #0 Not tainted
-----------------------------
net/sched/sch_api.c:304 suspicious rcu_dereference_protected() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
8 locks held by syz.2.231/4949:
#0: ffff88807715fd98 (&u->iolock){+.+.}-{3:3}, at: __unix_dgram_recvmsg+0x24d/0x1260 net/unix/af_unix.c:2301
#1: ffffc90000007be0 ((&peer->hb_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:45 [inline]
#1: ffffc90000007be0 ((&peer->hb_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbe/0x560 kernel/time/timer.c:1441
#2: ffff88807c3b24a0 (slock-AF_INET6){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
#2: ffff88807c3b24a0 (slock-AF_INET6){+.-.}-{2:2}, at: sctp_generate_heartbeat_event+0x8c/0x450 net/sctp/sm_sideeffect.c:371
#3: ffffffff8cb1fc60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
#4: ffffffff8cb1fcc0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
#5: ffffffff8cb1fcc0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
#6: ffff888021da1108 (&sch->q.lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
#6: ffff888021da1108 (&sch->q.lock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3879 [inline]
#6: ffff888021da1108 (&sch->q.lock){+.-.}-{2:2}, at: __dev_queue_xmit+0xc1f/0x32b0 net/core/dev.c:4221
#7: ffffffff8cb1fc60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
stack backtrace:
CPU: 0 PID: 4949 Comm: syz.2.231 Not tainted 5.15.173-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
qdisc_lookup+0xa8/0x630 net/sched/sch_api.c:304
qdisc_tree_reduce_backlog+0x212/0x4f0 net/sched/sch_api.c:800
pfifo_tail_enqueue+0x2ca/0x400 net/sched/sch_fifo.c:51
qdisc_enqueue include/net/sch_generic.h:832 [inline]
tbf_enqueue+0x345/0x6a0 net/sched/sch_tbf.c:237
dev_qdisc_enqueue+0x47/0x240 net/core/dev.c:3820
__dev_xmit_skb net/core/dev.c:3904 [inline]
__dev_queue_xmit+0xe32/0x32b0 net/core/dev.c:4221
neigh_hh_output include/net/neighbour.h:493 [inline]
neigh_output include/net/neighbour.h:507 [inline]
ip_finish_output2+0xcd7/0x11a0 net/ipv4/ip_output.c:228
dst_output include/net/dst.h:443 [inline]
ip_local_out net/ipv4/ip_output.c:126 [inline]
__ip_queue_xmit+0x12df/0x1d90 net/ipv4/ip_output.c:532
sctp_packet_transmit+0x2565/0x2b70 net/sctp/output.c:652
sctp_outq_flush_transports net/sctp/outqueue.c:1170 [inline]
sctp_outq_flush+0x13c7/0x3d70 net/sctp/outqueue.c:1218
sctp_side_effects net/sctp/sm_sideeffect.c:1199 [inline]
sctp_do_sm+0x55e7/0x5c80 net/sctp/sm_sideeffect.c:1170
sctp_generate_heartbeat_event+0x321/0x450 net/sctp/sm_sideeffect.c:391
call_timer_fn+0x16d/0x560 kernel/time/timer.c:1451
expire_timers kernel/time/timer.c:1496 [inline]
__run_timers+0x67c/0x890 kernel/time/timer.c:1767
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
handle_softirqs+0x3a7/0x930 kernel/softirq.c:558
__do_softirq kernel/softirq.c:592 [inline]
invoke_softirq kernel/softirq.c:432 [inline]
__irq_exit_rcu+0x157/0x240 kernel/softirq.c:641
irq_exit_rcu+0x5/0x20 kernel/softirq.c:653
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xd4/0x130 kernel/locking/spinlock.c:194
Code: 9c 8f 44 24 20 42 80 3c 23 00 74 08 4c 89 f7 e8 b2 0e 82 f7 f6 44 24 21 02 75 4e 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 57 3f 0f f7 65 8b 05 78 32 ba 75 85 c0 74 3f 48 c7 04 24 0e 36
RSP: 0018:ffffc900031df5a0 EFLAGS: 00000206
RAX: 2728896624306a00 RBX: 1ffff9200063beb8 RCX: ffffffff81632d68
RDX: dffffc0000000000 RSI: ffffffff8aab2a80 RDI: 0000000000000001
RBP: ffffc900031df630 R08: dffffc0000000000 R09: fffffbfff2131037
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: 1ffff9200063beb4 R14: ffffc900031df5c0 R15: 0000000000000246
spin_unlock_irqrestore include/linux/spinlock.h:418 [inline]
__wake_up_common_lock kernel/sched/wait.c:140 [inline]
__wake_up_sync_key+0x121/0x1c0 kernel/sched/wait.c:205
__unix_dgram_recvmsg+0x5fe/0x1260 net/unix/af_unix.c:2331
____sys_recvmsg+0x286/0x530
___sys_recvmsg+0x1ec/0x690 net/socket.c:2697
do_recvmmsg+0x36f/0x8f0 net/socket.c:2791
__sys_recvmmsg net/socket.c:2870 [inline]
__do_sys_recvmmsg net/socket.c:2893 [inline]
__se_sys_recvmmsg net/socket.c:2886 [inline]
__x64_sys_recvmmsg+0x195/0x240 net/socket.c:2886
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f50030a2d19
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:00007f5000ef2038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f5003293080 RCX: 00007f50030a2d19
RDX: 0000000000010106 RSI: 00000000200000c0 RDI: 0000000000000006
RBP: 00007f500311ea20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f5003293080 R15: 00007fffd69ead78
IPVS: sed: UDP 224.0.0.2:0 - no destination available
IPVS: sed: UDP 224.0.0.2:0 - no destination available
IPVS: sed: UDP 224.0.0.2:0 - no destination available
IPVS: sed: UDP 224.0.0.2:0 - no destination available
IPVS: sed: UDP 224.0.0.2:0 - no destination available
IPVS: sed: UDP 224.0.0.2:0 - no destination available
IPVS: sed: UDP 224.0.0.2:0 - no destination available
IPVS: sed: UDP 224.0.0.2:0 - no destination available
IPVS: sed: UDP 224.0.0.2:0 - no destination available
----------------
Code disassembly (best guess):
0: 9c pushf
1: 8f 44 24 20 pop 0x20(%rsp)
5: 42 80 3c 23 00 cmpb $0x0,(%rbx,%r12,1)
a: 74 08 je 0x14
c: 4c 89 f7 mov %r14,%rdi
f: e8 b2 0e 82 f7 call 0xf7820ec6
14: f6 44 24 21 02 testb $0x2,0x21(%rsp)
19: 75 4e jne 0x69
1b: 41 f7 c7 00 02 00 00 test $0x200,%r15d
22: 74 01 je 0x25
24: fb sti
25: bf 01 00 00 00 mov $0x1,%edi
* 2a: e8 57 3f 0f f7 call 0xf70f3f86 <-- trapping instruction
2f: 65 8b 05 78 32 ba 75 mov %gs:0x75ba3278(%rip),%eax # 0x75ba32ae
36: 85 c0 test %eax,%eax
38: 74 3f je 0x79
3a: 48 rex.W
3b: c7 .byte 0xc7
3c: 04 24 add $0x24,%al
3e: 0e (bad)
3f: 36 ss