=============================
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.1.217/5208:
#0: ffff8880739b4258 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
#0: ffff8880739b4258 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: zap_pte_range mm/memory.c:1342 [inline]
#0: ffff8880739b4258 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: zap_pmd_range mm/memory.c:1505 [inline]
#0: ffff8880739b4258 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: zap_pud_range mm/memory.c:1534 [inline]
#0: ffff8880739b4258 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: zap_p4d_range mm/memory.c:1555 [inline]
#0: ffff8880739b4258 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: unmap_page_range+0x98d/0x2520 mm/memory.c:1576
#1: ffffc90000007be0 ((&d->timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:45 [inline]
#1: ffffc90000007be0 ((&d->timer)){+.-.}-{0:0}, at: call_timer_fn+0xbb/0x530 kernel/time/timer.c:1441
#2: ffffffff8c11c660 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
#3: ffffffff8c11c6c0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
#4: ffff888061aaa108 (&sch->q.lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
#4: ffff888061aaa108 (&sch->q.lock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3911 [inline]
#4: ffff888061aaa108 (&sch->q.lock){+.-.}-{2:2}, at: __dev_queue_xmit+0xb8a/0x2ed0 net/core/dev.c:4253
#5: ffff888061aaa148 (dev->qdisc_running_key ?: &qdisc_running_key){+...}-{0:0}, at: tipc_l2_send_msg+0x30a/0x3c0 net/tipc/bearer.c:518
#6: ffffffff8c11c660 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
stack backtrace:
CPU: 0 PID: 5208 Comm: syz.1.217 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
sfq_enqueue+0x148e/0x2260 net/sched/sch_sfq.c:-1
qdisc_enqueue include/net/sch_generic.h:832 [inline]
netem_dequeue+0xd39/0x1400 net/sched/sch_netem.c:737
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
__dev_xmit_skb net/core/dev.c:3942 [inline]
__dev_queue_xmit+0xeb9/0x2ed0 net/core/dev.c:4253
tipc_l2_send_msg+0x30a/0x3c0 net/tipc/bearer.c:518
tipc_bearer_xmit_skb+0x292/0x3c0 net/tipc/bearer.c:577
tipc_disc_timeout+0x568/0x6b0 net/tipc/discover.c:338
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:__sanitizer_cov_trace_const_cmp8+0x0/0x80 kernel/kcov.c:301
Code: 28 4d 39 ca 77 22 89 ff 89 f6 4a c7 44 02 08 05 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 90 <48> 8b 04 24 65 48 8b 0d b4 a0 8a 7e 65 8b 15 b5 a0 8a 7e 81 e2 00
RSP: 0018:ffffc900031af558 EFLAGS: 00000246
RAX: 1ffffd4000322cf0 RBX: 00fff0000000000a RCX: ffff88802c04d940
RDX: 0000000000000000 RSI: 00fff0000000000a RDI: ffffffffffffffff
RBP: ffffc900031af6d0 R08: dffffc0000000000 R09: ffffed1005809b29
R10: ffffed1005809b29 R11: 1ffff11005809b28 R12: ffffea0001916780
R13: ffffea0001916788 R14: dffffc0000000000 R15: ffffea0001916780
PagePoisoned include/linux/page-flags.h:218 [inline]
PageSwapBacked include/linux/page-flags.h:371 [inline]
mm_counter_file include/linux/mm.h:1977 [inline]
mm_counter include/linux/mm.h:1986 [inline]
zap_pte_range mm/memory.c:1383 [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+0xef9/0x2520 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: 0033:0x7f074e1e2ba9
Code: Unable to access opcode bytes at RIP 0x7f074e1e2b7f.
RSP: 002b:00007f074c44a0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f074e429fa8 RCX: 00007f074e1e2ba9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f074e429fa8
RBP: 00007f074e429fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f074e42a038 R14: 00007ffd44bd9c60 R15: 00007ffd44bd9d48
----------------
Code disassembly (best guess):
0: 28 4d 39 sub %cl,0x39(%rbp)
3: ca 77 22 lret $0x2277
6: 89 ff mov %edi,%edi
8: 89 f6 mov %esi,%esi
a: 4a c7 44 02 08 05 00 movq $0x5,0x8(%rdx,%r8,1)
11: 00 00
13: 4a 89 7c 02 10 mov %rdi,0x10(%rdx,%r8,1)
18: 4a 89 74 02 18 mov %rsi,0x18(%rdx,%r8,1)
1d: 4a 89 44 02 20 mov %rax,0x20(%rdx,%r8,1)
22: 48 ff c1 inc %rcx
25: 48 89 0a mov %rcx,(%rdx)
28: c3 ret
29: 90 nop
* 2a: 48 8b 04 24 mov (%rsp),%rax <-- trapping instruction
2e: 65 48 8b 0d b4 a0 8a mov %gs:0x7e8aa0b4(%rip),%rcx # 0x7e8aa0ea
35: 7e
36: 65 8b 15 b5 a0 8a 7e mov %gs:0x7e8aa0b5(%rip),%edx # 0x7e8aa0f2
3d: 81 .byte 0x81
3e: e2 00 loop 0x40