=============================
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.2.639/8168:
#0: ffff888027806798 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
#0: ffff888027806798 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: zap_pte_range mm/memory.c:1342 [inline]
#0: ffff888027806798 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: zap_pmd_range mm/memory.c:1505 [inline]
#0: ffff888027806798 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: zap_pud_range mm/memory.c:1534 [inline]
#0: ffff888027806798 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: zap_p4d_range mm/memory.c:1555 [inline]
#0: ffff888027806798 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: unmap_page_range+0x98d/0x2520 mm/memory.c:1576
#1: ffffffff8c11bfa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
#2: ffffffff8c11bfa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
#3: ffff88807b7f1148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: net_tx_action+0x6bc/0x870 net/core/dev.c:5128
#4: ffff88807b7f1108 (&sch->q.lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
#4: ffff88807b7f1108 (&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: 8168 Comm: syz.2.639 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:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:202
Code: 66 2e 0f 1f 84 00 00 00 00 00 53 48 89 fb e8 17 00 00 00 48 8b 3d 00 ec f0 0b 48 89 de 5b e9 47 ae 44 00 00 00 cc cc 00 00 cc <48> 8b 04 24 65 48 8b 0d 94 ad 8a 7e 65 8b 15 95 ad 8a 7e 81 e2 00
RSP: 0018:ffffc900032e7818 EFLAGS: 00000246
RAX: ffffffff81b82e17 RBX: ffffea000198b540 RCX: ffff88802709d940
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: dffffc0000000000 R09: fffff940003316a9
R10: fffff940003316a9 R11: 1ffffd40003316a8 R12: 0000000000000000
R13: ffffea000198b540 R14: 0000000000000000 R15: dffffc0000000000
PageHuge+0x92/0x130 mm/hugetlb.c:1742
page_remove_file_rmap mm/rmap.c:1260 [inline]
page_remove_rmap+0x621/0x10f0 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: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: 0033:0x7f5413596929
Code: Unable to access opcode bytes at RIP 0x7f54135968ff.
RSP: 002b:00007fff114f0068 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5413596929
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fff114f00cc R08: 00000009114f015f R09: 00000000000927c0
R10: 0000000000007dc8 R11: 0000000000000246 R12: 000000000000000e
R13: 00000000000927c0 R14: 000000000003b2b4 R15: 00007fff114f0120
----------------
Code disassembly (best guess):
0: 66 2e 0f 1f 84 00 00 cs nopw 0x0(%rax,%rax,1)
7: 00 00 00
a: 53 push %rbx
b: 48 89 fb mov %rdi,%rbx
e: e8 17 00 00 00 call 0x2a
13: 48 8b 3d 00 ec f0 0b mov 0xbf0ec00(%rip),%rdi # 0xbf0ec1a
1a: 48 89 de mov %rbx,%rsi
1d: 5b pop %rbx
1e: e9 47 ae 44 00 jmp 0x44ae6a
23: 00 00 add %al,(%rax)
25: cc int3
26: cc int3
27: 00 00 add %al,(%rax)
29: cc int3
* 2a: 48 8b 04 24 mov (%rsp),%rax <-- trapping instruction
2e: 65 48 8b 0d 94 ad 8a mov %gs:0x7e8aad94(%rip),%rcx # 0x7e8aadca
35: 7e
36: 65 8b 15 95 ad 8a 7e mov %gs:0x7e8aad95(%rip),%edx # 0x7e8aadd2
3d: 81 .byte 0x81
3e: e2 00 loop 0x40