=============================
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
10 locks held by dhcpcd-run-hook/6128:
#0: ffffffff8cbab1b0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mmap kernel/fork.c:503 [inline]
#0: ffffffff8cbab1b0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1466 [inline]
#0: ffffffff8cbab1b0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x223/0x1370 kernel/fork.c:1518
#1: ffff8880595bdc28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#1: ffff8880595bdc28 (&mm->mmap_lock){++++}-{3:3}, at: dup_mmap kernel/fork.c:504 [inline]
#1: ffff8880595bdc28 (&mm->mmap_lock){++++}-{3:3}, at: dup_mm kernel/fork.c:1466 [inline]
#1: ffff8880595bdc28 (&mm->mmap_lock){++++}-{3:3}, at: copy_mm+0x242/0x1370 kernel/fork.c:1518
#2: ffff8880595bea28 (&mm->mmap_lock/1){+.+.}-{3:3}, at: mmap_write_lock_nested include/linux/mmap_lock.h:78 [inline]
#2: ffff8880595bea28 (&mm->mmap_lock/1){+.+.}-{3:3}, at: dup_mmap kernel/fork.c:513 [inline]
#2: ffff8880595bea28 (&mm->mmap_lock/1){+.+.}-{3:3}, at: dup_mm kernel/fork.c:1466 [inline]
#2: ffff8880595bea28 (&mm->mmap_lock/1){+.+.}-{3:3}, at: copy_mm+0x35c/0x1370 kernel/fork.c:1518
#3: ffffc90000007be0 ((&peer->hb_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:45 [inline]
#3: ffffc90000007be0 ((&peer->hb_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbe/0x560 kernel/time/timer.c:1441
#4: ffff88814cdd63a0 (slock-AF_INET6){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
#4: ffff88814cdd63a0 (slock-AF_INET6){+.-.}-{2:2}, at: sctp_generate_heartbeat_event+0x8c/0x450 net/sctp/sm_sideeffect.c:371
#5: ffffffff8cb1fd20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
#6: ffffffff8cb1fd80 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
#7: ffffffff8cb1fd80 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
#8: ffff88805ad31908 (&sch->q.lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
#8: ffff88805ad31908 (&sch->q.lock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3879 [inline]
#8: ffff88805ad31908 (&sch->q.lock){+.-.}-{2:2}, at: __dev_queue_xmit+0xc1f/0x32b0 net/core/dev.c:4221
#9: ffffffff8cb1fd20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
stack backtrace:
CPU: 0 PID: 6128 Comm: dhcpcd-run-hook 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:vm_start_gap include/linux/mm.h:2735 [inline]
RIP: 0010:vma_compute_gap mm/mmap.c:300 [inline]
RIP: 0010:vma_compute_subtree_gap mm/mmap.c:314 [inline]
RIP: 0010:validate_mm_rb+0x87/0x230 mm/mmap.c:385
Code: 4c 89 f8 48 c1 e8 03 42 80 3c 30 00 74 08 4c 89 ff e8 ed 71 0e 00 4c 8b 6b e0 48 8d 6b 30 48 89 e8 48 c1 e8 03 42 80 3c 30 00 <74> 08 48 89 ef e8 cf 71 0e 00 48 8b 6d 00 be 00 01 00 00 48 21 ee
RSP: 0018:ffffc900030af8c8 EFLAGS: 00000246
RAX: 1ffff1100ce32196 RBX: ffff888067190c80 RCX: ffff888026d81dc0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888067190b78
RBP: ffff888067190cb0 R08: ffffffff81bbef5d R09: ffff888067192550
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: 00007ff9ce344000 R14: dffffc0000000000 R15: ffff888067190c60
vma_rb_insert mm/mmap.c:457 [inline]
__vma_link_rb+0x505/0x530 mm/mmap.c:656
dup_mmap kernel/fork.c:609 [inline]
dup_mm kernel/fork.c:1466 [inline]
copy_mm+0xc08/0x1370 kernel/fork.c:1518
copy_process+0x1816/0x3ef0 kernel/fork.c:2205
kernel_clone+0x210/0x960 kernel/fork.c:2603
__do_sys_clone kernel/fork.c:2720 [inline]
__se_sys_clone kernel/fork.c:2704 [inline]
__x64_sys_clone+0x23f/0x290 kernel/fork.c:2704
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: 0033:0x7ff9ce181a12
Code: 41 5d 41 5e 41 5f c3 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 10 48 8b 15 e7 43 0f 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffd6ac65058 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007ff9ce181a12
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00005609b5f68b70 R08: 0000000000000000 R09: 0000000000000200
R10: 00007ff9ce047650 R11: 0000000000000246 R12: 0000000000000084
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000024
----------------
Code disassembly (best guess):
0: 4c 89 f8 mov %r15,%rax
3: 48 c1 e8 03 shr $0x3,%rax
7: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1)
c: 74 08 je 0x16
e: 4c 89 ff mov %r15,%rdi
11: e8 ed 71 0e 00 call 0xe7203
16: 4c 8b 6b e0 mov -0x20(%rbx),%r13
1a: 48 8d 6b 30 lea 0x30(%rbx),%rbp
1e: 48 89 e8 mov %rbp,%rax
21: 48 c1 e8 03 shr $0x3,%rax
25: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1)
* 2a: 74 08 je 0x34 <-- trapping instruction
2c: 48 89 ef mov %rbp,%rdi
2f: e8 cf 71 0e 00 call 0xe7203
34: 48 8b 6d 00 mov 0x0(%rbp),%rbp
38: be 00 01 00 00 mov $0x100,%esi
3d: 48 21 ee and %rbp,%rsi