=============================
WARNING: suspicious RCU usage
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
11 locks held by syz.1.87/4622:
#0: ffff888078cac978 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:364 [inline]
#0: ffff888078cac978 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: zap_pte_range mm/memory.c:1342 [inline]
#0: ffff888078cac978 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: zap_pmd_range mm/memory.c:1505 [inline]
#0: ffff888078cac978 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: zap_pud_range mm/memory.c:1534 [inline]
#0: ffff888078cac978 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: zap_p4d_range mm/memory.c:1555 [inline]
#0: ffff888078cac978 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: unmap_page_range+0x98d/0x2520 mm/memory.c:1576
#1: ffffffff8c11c760 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
#2: ffffc90000007be0 ((&ndev->rs_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:45 [inline]
#2: ffffc90000007be0 ((&ndev->rs_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbb/0x530 kernel/time/timer.c:1441
#3: ffffffff8c11c760 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
#4: ffffffff8c11c7c0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#5: ffffffff8c11c7c0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#6: ffffffff8c11c760 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
#7: ffffffff8c11c7c0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#8: ffffffff8c11c7c0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#9: ffff888073f43108 (&sch->q.lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:364 [inline]
#9: ffff888073f43108 (&sch->q.lock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3911 [inline]
#9: ffff888073f43108 (&sch->q.lock){+.-.}-{2:2}, at: __dev_queue_xmit+0xb8a/0x2ed0 net/core/dev.c:4253
#10: ffffffff8c11c760 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
stack backtrace:
CPU: 0 PID: 4622 Comm: syz.1.87 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
qdisc_lookup+0xa6/0x650 net/sched/sch_api.c:304
qdisc_tree_reduce_backlog+0x190/0x430 net/sched/sch_api.c:793
sfq_enqueue+0x1164/0x2260 net/sched/sch_sfq.c:471
qdisc_enqueue include/net/sch_generic.h:832 [inline]
tbf_enqueue+0x224/0x6e0 net/sched/sch_tbf.c:243
dev_qdisc_enqueue+0x48/0x210 net/core/dev.c:3852
__dev_xmit_skb net/core/dev.c:3936 [inline]
__dev_queue_xmit+0xd7e/0x2ed0 net/core/dev.c:4253
neigh_hh_output include/net/neighbour.h:493 [inline]
neigh_output include/net/neighbour.h:507 [inline]
ip_finish_output2+0xc69/0x1080 net/ipv4/ip_output.c:228
iptunnel_xmit+0x525/0x960 net/ipv4/ip_tunnel_core.c:82
udp_tunnel_xmit_skb+0x1b7/0x280 net/ipv4/udp_tunnel_core.c:175
geneve_xmit_skb drivers/net/geneve.c:1006 [inline]
geneve_xmit+0x24dd/0x3070 drivers/net/geneve.c:1119
__netdev_start_xmit include/linux/netdevice.h:5036 [inline]
netdev_start_xmit include/linux/netdevice.h:5050 [inline]
xmit_one net/core/dev.c:3649 [inline]
dev_hard_start_xmit+0x2a5/0x7e0 net/core/dev.c:3665
__dev_queue_xmit+0x19df/0x2ed0 net/core/dev.c:4288
neigh_hh_output include/net/neighbour.h:493 [inline]
neigh_output include/net/neighbour.h:507 [inline]
ip6_finish_output2+0x1035/0x1500 net/ipv6/ip6_output.c:130
dst_output include/net/dst.h:452 [inline]
NF_HOOK include/linux/netfilter.h:302 [inline]
ndisc_send_skb+0xbea/0x14a0 net/ipv6/ndisc.c:513
addrconf_rs_timer+0x2b8/0x600 net/ipv6/addrconf.c:3956
call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451
expire_timers kernel/time/timer.c:1496 [inline]
__run_timers+0x525/0x7c0 kernel/time/timer.c:1767
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
handle_softirqs+0x328/0x820 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659
irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
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:check_kcov_mode kernel/kcov.c:183 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x32/0x60 kernel/kcov.c:206
Code: a4 a3 8a 7e 65 8b 15 a5 a3 8a 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 34 16 00 00 00 74 2c 8b 91 10 16 00 00 <83> fa 02 75 21 48 8b 91 18 16 00 00 48 8b 32 48 8d 7e 01 8b 89 14
RSP: 0018:ffffc9000347f500 EFLAGS: 00000246
RAX: ffffffff81b0252d RBX: ffff88807aca7301 RCX: ffff88807a8a5940
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000002
RBP: 0000000000000000 R08: dffffc0000000000 R09: fffff940003986df
R10: fffff940003986df R11: 1ffffd40003986de R12: ffffea0001cc36c8
R13: ffffea0001cc36c0 R14: dffffc0000000000 R15: ffffea0001cc36d8
page_remove_file_rmap mm/rmap.c:1283 [inline]
page_remove_rmap+0x66d/0x10f0 mm/rmap.c:1354
zap_pte_range mm/memory.c:1384 [inline]
zap_pmd_range mm/memory.c:1505 [inline]
zap_pud_range mm/memory.c:1534 [inline]
zap_p4d_range mm/memory.c:1555 [inline]
unmap_page_range+0xfbc/0x2520 mm/memory.c:1576
unmap_vmas+0x11b/0x230 mm/memory.c:1653
exit_mmap+0x38f/0x5f0 mm/mmap.c:3216
__mmput+0x115/0x3b0 kernel/fork.c:1127
exit_mm+0x567/0x6c0 kernel/exit.c:550
do_exit+0x5a1/0x20a0 kernel/exit.c:870
do_group_exit+0x12e/0x300 kernel/exit.c:997
get_signal+0x6ca/0x12c0 kernel/signal.c:2900
arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867
handle_signal_work kernel/entry/common.c:154 [inline]
exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f94902eafc9
Code: Unable to access opcode bytes at RIP 0x7f94902eaf9f.
RSP: 002b:00007f948e510038 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 00007f9490542180 RCX: 00007f94902eafc9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007f949036df91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9490542218 R14: 00007f9490542180 R15: 00007ffe6a371208
----------------
Code disassembly (best guess):
0: a4 movsb %ds:(%rsi),%es:(%rdi)
1: a3 8a 7e 65 8b 15 a5 movabs %eax,0x8aa3a5158b657e8a
8: a3 8a
a: 7e 81 jle 0xffffff8d
c: e2 00 loop 0xe
e: 01 ff add %edi,%edi
10: 00 74 11 81 add %dh,-0x7f(%rcx,%rdx,1)
14: fa cli
15: 00 01 add %al,(%rcx)
17: 00 00 add %al,(%rax)
19: 75 35 jne 0x50
1b: 83 b9 34 16 00 00 00 cmpl $0x0,0x1634(%rcx)
22: 74 2c je 0x50
24: 8b 91 10 16 00 00 mov 0x1610(%rcx),%edx
* 2a: 83 fa 02 cmp $0x2,%edx <-- trapping instruction
2d: 75 21 jne 0x50
2f: 48 8b 91 18 16 00 00 mov 0x1618(%rcx),%rdx
36: 48 8b 32 mov (%rdx),%rsi
39: 48 8d 7e 01 lea 0x1(%rsi),%rdi
3d: 8b .byte 0x8b
3e: 89 .byte 0x89
3f: 14 .byte 0x14