=============================
WARNING: suspicious RCU usage
5.15.174-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
7 locks held by syz.0.1053/9356:
#0: ffffc90000007be0 ((&peer->hb_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:45 [inline]
#0: ffffc90000007be0 ((&peer->hb_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbe/0x560 kernel/time/timer.c:1441
#1: ffff88802a21daa0 (slock-AF_INET6){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
#1: ffff88802a21daa0 (slock-AF_INET6){+.-.}-{2:2}, at: sctp_generate_heartbeat_event+0x8c/0x450 net/sctp/sm_sideeffect.c:371
#2: ffffffff8cb1fd20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
#3: ffffffff8cb1fd80 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
#4: ffffffff8cb1fd80 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
#5: ffff8880797d9108 (&sch->q.lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
#5: ffff8880797d9108 (&sch->q.lock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3879 [inline]
#5: ffff8880797d9108 (&sch->q.lock){+.-.}-{2:2}, at: __dev_queue_xmit+0xc1f/0x32b0 net/core/dev.c:4221
#6: ffffffff8cb1fd20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
stack backtrace:
CPU: 0 PID: 9356 Comm: syz.0.1053 Not tainted 5.15.174-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
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+0x35d/0x6f0 net/sched/sch_tbf.c:243
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:lock_acquire+0xf0/0x4f0 kernel/locking/lockdep.c:5596
Code: 00 e8 a4 93 67 00 89 d8 48 0f a3 05 52 92 a7 0c 73 0d e8 83 6b 08 00 84 c0 0f 84 b9 02 00 00 48 c7 c0 d4 93 0a 8e 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 dd 02 00 00 83 3d d0 c5 a7 0c 00 0f 84
RSP: 0018:ffffc900031bf8c0 EFLAGS: 00000a03
RAX: 1ffffffff1c1527a RBX: 0000000000000000 RCX: ffffffff8162cdcc
RDX: 0000000000000000 RSI: ffffffff8af9efe0 RDI: ffffffff8af9efa0
RBP: ffffc900031bfa08 R08: dffffc0000000000 R09: fffffbfff1c14c06
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000637f20
R13: dffffc0000000000 R14: 0000000000000000 R15: ffffffff8af9b480
__might_fault+0xb4/0x110 mm/memory.c:5355
_copy_from_user+0x28/0x170 lib/usercopy.c:14
copy_from_user include/linux/uaccess.h:192 [inline]
__copy_msghdr_from_user net/socket.c:2318 [inline]
copy_msghdr_from_user net/socket.c:2369 [inline]
recvmsg_copy_msghdr net/socket.c:2621 [inline]
___sys_recvmsg+0x150/0x690 net/socket.c:2693
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: 0033:0x7ff2ee86ad19
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:00007ff2ec6db038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007ff2eea5afa0 RCX: 00007ff2ee86ad19
RDX: 0000000000010106 RSI: 00000000200000c0 RDI: 0000000000000004
RBP: 00007ff2ee8e6a20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007ff2eea5afa0 R15: 00007fff1d996d08
----------------
Code disassembly (best guess):
0: 00 e8 add %ch,%al
2: a4 movsb %ds:(%rsi),%es:(%rdi)
3: 93 xchg %eax,%ebx
4: 67 00 89 d8 48 0f a3 add %cl,-0x5cf0b728(%ecx)
b: 05 52 92 a7 0c add $0xca79252,%eax
10: 73 0d jae 0x1f
12: e8 83 6b 08 00 call 0x86b9a
17: 84 c0 test %al,%al
19: 0f 84 b9 02 00 00 je 0x2d8
1f: 48 c7 c0 d4 93 0a 8e mov $0xffffffff8e0a93d4,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 0f b6 04 28 movzbl (%rax,%r13,1),%eax <-- trapping instruction
2f: 84 c0 test %al,%al
31: 0f 85 dd 02 00 00 jne 0x314
37: 83 3d d0 c5 a7 0c 00 cmpl $0x0,0xca7c5d0(%rip) # 0xca7c60e
3e: 0f .byte 0xf
3f: 84 .byte 0x84