=============================
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
7 locks held by syz.1.232/5220:
#0: ffff88807e017828 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock include/linux/mmap_lock.h:117 [inline]
#0: ffff88807e017828 (&mm->mmap_lock){++++}-{3:3}, at: __mm_populate+0x15e/0x3a0 mm/gup.c:1618
#1: ffffffff8c11c660 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
#2: ffff88802787f018 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
#2: ffff88802787f018 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: filemap_map_pages+0xb7d/0x1390 mm/filemap.c:3324
#3: ffffffff8c11c660 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
#4: ffff8880786ce948 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: net_tx_action+0x6bc/0x870 net/core/dev.c:5128
#5: ffff8880786ce908 (&sch->q.lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
#5: ffff8880786ce908 (&sch->q.lock){+.-.}-{2:2}, at: sch_direct_xmit+0x305/0x4a0 net/sched/sch_generic.c:354
#6: ffffffff8c11c660 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
stack backtrace:
CPU: 1 PID: 5220 Comm: syz.1.232 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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
cake_dequeue+0x1b8f/0x4aa0 net/sched/sch_cake.c:2199
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:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:226 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp1+0x4/0x80 kernel/kcov.c:279
Code: 77 1e 4a c7 44 02 08 06 00 00 00 4a 89 7c 02 10 4a 89 74 02 18 4a 89 44 02 20 48 ff c1 48 89 0a c3 0f 1f 44 00 00 48 8b 04 24 <65> 48 8b 0d 34 a2 8a 7e 65 8b 15 35 a2 8a 7e 81 e2 00 01 ff 00 74
RSP: 0018:ffffc900033df6f0 EFLAGS: 00000246
RAX: ffffffff819c87b5 RBX: dffffc0000000000 RCX: ffff8880591fd940
RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: dffffc0000000000 R09: fffff940002ed32f
R10: fffff940002ed32f R11: 1ffffd40002ed32e R12: ffff88805f550dc0
R13: ffffc900033df9f0 R14: 0000000000000000 R15: ffffc900033df820
xas_next_entry+0x85/0x3d0 include/linux/xarray.h:1647
next_map_page mm/filemap.c:3296 [inline]
filemap_map_pages+0xeaa/0x1390 mm/filemap.c:3352
do_fault_around mm/memory.c:4243 [inline]
do_read_fault mm/memory.c:4258 [inline]
do_fault mm/memory.c:4392 [inline]
handle_pte_fault mm/memory.c:4650 [inline]
__handle_mm_fault mm/memory.c:4785 [inline]
handle_mm_fault+0x2580/0x43c0 mm/memory.c:4883
faultin_page mm/gup.c:976 [inline]
__get_user_pages+0x93e/0x11c0 mm/gup.c:1197
populate_vma_page_range+0x213/0x290 mm/gup.c:1529
__mm_populate+0x26f/0x3a0 mm/gup.c:1638
mm_populate include/linux/mm.h:2646 [inline]
vm_mmap_pgoff+0x203/0x2b0 mm/util.c:556
ksys_mmap_pgoff+0x140/0x780 mm/mmap.c:1635
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: 0033:0x7fcabcb65ba9
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:00007fcabadcd038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fcabcdacfa0 RCX: 00007fcabcb65ba9
RDX: b635773f06ebbeef RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007fcabcbe8e19 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcabcdad038 R14: 00007fcabcdacfa0 R15: 00007ffcf4341ad8
----------------
Code disassembly (best guess):
0: 77 1e ja 0x20
2: 4a c7 44 02 08 06 00 movq $0x6,0x8(%rdx,%r8,1)
9: 00 00
b: 4a 89 7c 02 10 mov %rdi,0x10(%rdx,%r8,1)
10: 4a 89 74 02 18 mov %rsi,0x18(%rdx,%r8,1)
15: 4a 89 44 02 20 mov %rax,0x20(%rdx,%r8,1)
1a: 48 ff c1 inc %rcx
1d: 48 89 0a mov %rcx,(%rdx)
20: c3 ret
21: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
26: 48 8b 04 24 mov (%rsp),%rax
* 2a: 65 48 8b 0d 34 a2 8a mov %gs:0x7e8aa234(%rip),%rcx # 0x7e8aa266 <-- trapping instruction
31: 7e
32: 65 8b 15 35 a2 8a 7e mov %gs:0x7e8aa235(%rip),%edx # 0x7e8aa26e
39: 81 e2 00 01 ff 00 and $0xff0100,%edx
3f: 74 .byte 0x74