=============================
WARNING: suspicious RCU usage
5.15.185-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
6 locks held by syz.4.957/7811:
#0: ffff88807770dc18 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
#0: ffff88807770dc18 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: zap_pte_range mm/memory.c:1342 [inline]
#0: ffff88807770dc18 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: zap_pmd_range mm/memory.c:1505 [inline]
#0: ffff88807770dc18 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: zap_pud_range mm/memory.c:1534 [inline]
#0: ffff88807770dc18 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: zap_p4d_range mm/memory.c:1555 [inline]
#0: ffff88807770dc18 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: unmap_page_range+0x98d/0x2520 mm/memory.c:1576
#1: ffff8880b9135528 (lock#5){+.+.}-{2:2}, at: local_lock_acquire+0xe/0x170 include/linux/local_lock_internal.h:28
#2: ffffffff8c11bfa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
#3: ffff888077e12148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: net_tx_action+0x6bc/0x870 net/core/dev.c:5128
#4: ffff888077e12108 (&sch->q.lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
#4: ffff888077e12108 (&sch->q.lock){+.-.}-{2:2}, at: sch_direct_xmit+0x305/0x4a0 net/sched/sch_generic.c:354
#5: ffffffff8c11bfa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
stack backtrace:
CPU: 1 PID: 7811 Comm: syz.4.957 Not tainted 5.15.185-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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+0x213/0x4e0 net/sched/sch_api.c:800
cake_dequeue+0x1b8f/0x4aa0 net/sched/sch_cake.c:2189
qdisc_peek_dequeued+0x6e/0x1f0 include/net/sch_generic.h:1115
tbf_dequeue+0x7d/0xce0 net/sched/sch_tbf.c:265
dequeue_skb net/sched/sch_generic.c:292 [inline]
qdisc_restart net/sched/sch_generic.c:397 [inline]
__qdisc_run+0x237/0x1480 net/sched/sch_generic.c:415
qdisc_run+0x103/0x2f0 include/net/pkt_sched.h:132
net_tx_action+0x6bc/0x870 net/core/dev.c:5128
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:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194
Code: 74 05 e8 3e 14 d3 f7 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 06 94 a6 f7 65 8b 05 a7 a3 57 76 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc90002f2f6a0 EFLAGS: 00000206
RAX: 6602f1e0d1999300 RBX: 0000000000000a02 RCX: 6602f1e0d1999300
RDX: dffffc0000000000 RSI: ffffffff8a0b11c0 RDI: 0000000000000001
RBP: ffffc90002f2f730 R08: dffffc0000000000 R09: fffffbfff1ff3621
R10: fffffbfff1ff3621 R11: 1ffffffff1ff3620 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffff88807daac050 R15: 1ffff920005e5ed4
spin_unlock_irqrestore include/linux/spinlock.h:418 [inline]
unlock_page_lruvec_irqrestore include/linux/memcontrol.h:1538 [inline]
pagevec_lru_move_fn+0x4a8/0x5e0 mm/swap.c:202
activate_page mm/swap.c:338 [inline]
mark_page_accessed+0xe01/0x12b0 mm/swap.c:422
zap_pte_range mm/memory.c:1381 [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+0xe10/0x2520 mm/memory.c:1576
unmap_vmas+0x11b/0x230 mm/memory.c:1653
exit_mmap+0x38f/0x5f0 mm/mmap.c:3204
__mmput+0x115/0x3b0 kernel/fork.c:1127
exit_mm+0x567/0x6c0 kernel/exit.c:550
do_exit+0x599/0x20a0 kernel/exit.c:861
do_group_exit+0x12e/0x300 kernel/exit.c:996
__do_sys_exit_group kernel/exit.c:1007 [inline]
__se_sys_exit_group kernel/exit.c:1005 [inline]
__x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1005
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: 0033:0x7f202d5b8929
Code: Unable to access opcode bytes at RIP 0x7f202d5b88ff.
RSP: 002b:00007ffe2ac21928 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f202d5b8929
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffe2ac2198c R08: 0000001c2ac21a1f R09: 00000000000927c0
R10: 000000000001bb8c R11: 0000000000000246 R12: 00000000000000c5
R13: 00000000000927c0 R14: 000000000004c668 R15: 00007ffe2ac219e0
----------------
Code disassembly (best guess):
0: 74 05 je 0x7
2: e8 3e 14 d3 f7 call 0xf7d31445
7: 48 c7 44 24 20 00 00 movq $0x0,0x20(%rsp)
e: 00 00
10: 9c pushf
11: 8f 44 24 20 pop 0x20(%rsp)
15: f6 44 24 21 02 testb $0x2,0x21(%rsp)
1a: 75 4b jne 0x67
1c: f7 c3 00 02 00 00 test $0x200,%ebx
22: 74 01 je 0x25
24: fb sti
25: bf 01 00 00 00 mov $0x1,%edi
* 2a: e8 06 94 a6 f7 call 0xf7a69435 <-- trapping instruction
2f: 65 8b 05 a7 a3 57 76 mov %gs:0x7657a3a7(%rip),%eax # 0x7657a3dd
36: 85 c0 test %eax,%eax
38: 74 3c je 0x76
3a: 48 rex.W
3b: c7 .byte 0xc7
3c: 04 24 add $0x24,%al
3e: 0e (bad)
3f: 36 ss