------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 9921 at lib/refcount.c:28 refcount_warn_saturate+0x11a/0x1d0 lib/refcount.c:28
Modules linked in:
CPU: 0 UID: 0 PID: 9921 Comm: syz.5.948 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:refcount_warn_saturate+0x11a/0x1d0 lib/refcount.c:28
Code: a0 ba e2 8b e8 77 c3 ba fc 90 0f 0b 90 90 eb d7 e8 9b 26 f7 fc c6 05 13 13 c5 0a 01 90 48 c7 c7 00 bb e2 8b e8 57 c3 ba fc 90 <0f> 0b 90 90 eb b7 e8 7b 26 f7 fc c6 05 f0 12 c5 0a 01 90 48 c7 c7
RSP: 0018:ffffc90000007b88 EFLAGS: 00010246
RAX: 5e1332d3ac458c00 RBX: 0000000000000003 RCX: ffff888026fc9e00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffffc90000007c90 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1bfa22c R12: 1ffff92000000f78
R13: ffff8880575f91b8 R14: ffff8880575f9020 R15: 0000000000000000
FS: 00007fe0235426c0(0000) GS:ffff888125c12000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000021ba8000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
call_timer_fn+0x17b/0x5f0 kernel/time/timer.c:1747
expire_timers kernel/time/timer.c:1798 [inline]
__run_timers kernel/time/timer.c:2372 [inline]
__run_timer_base+0x61a/0x860 kernel/time/timer.c:2384
run_timer_base kernel/time/timer.c:2393 [inline]
run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2403
handle_softirqs+0x283/0x870 kernel/softirq.c:579
__do_softirq kernel/softirq.c:613 [inline]
invoke_softirq kernel/softirq.c:453 [inline]
__irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:raw_spin_rq_unlock_irq+0x13/0x90 kernel/sched/sched.h:1532
Code: cc e8 d1 27 e8 09 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 41 57 41 56 53 66 90 e8 74 be ea 09 e8 af 27 35 00 fb 5b <41> 5e 41 5f e9 d4 0c eb 09 cc f3 0f 1e fa 49 be 00 00 00 00 00 fc
RSP: 0018:ffffc90004896c08 EFLAGS: 00000286
RAX: 5e1332d3ac458c00 RBX: ffff8880b8639f80 RCX: 5e1332d3ac458c00
RDX: 0000000000000000 RSI: ffffffff8d9ba32d RDI: ffffffff8be33f80
RBP: ffffc90004896e30 R08: ffffffff8fa3a837 R09: 1ffffffff1f47506
R10: dffffc0000000000 R11: fffffbfff1f47507 R12: dffffc0000000000
R13: 0000000000000000 R14: ffff888026fc9e00 R15: 1ffff110170c7551
__schedule+0x19e0/0x4cc0 kernel/sched/core.c:6969
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288
irqentry_exit+0x6f/0x90 kernel/entry/common.c:197
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:tc_cls_act_func_proto+0x6a/0x720 net/core/filter.c:8224
Code: 5e 0f 8f db 03 00 00 83 fd 55 0f 84 b5 05 00 00 83 fd 56 0f 85 b5 06 00 00 e8 52 8d 50 f8 48 c7 c0 80 0d 95 8c e9 9c 06 00 00 <83> fd 1b 0f 8e 8b 00 00 00 83 fd 25 0f 8e bc 00 00 00 83 fd 2a 0f
RSP: 0018:ffffc90004896fa8 EFLAGS: 00000283
RAX: 000000000000003b RBX: ffffc900039c3000 RCX: 0000000000000005
RDX: ffffffff896f1ffe RSI: ffffffff8f53f3e0 RDI: 0000000000000007
RBP: 0000000000000007 R08: ffff888026fc9e00 R09: 000000000000003b
R10: 00000000000000cf R11: 0000000000000002 R12: 1ffff92000912e14
R13: ffffc900039c3000 R14: ffff888078ed0000 R15: dffffc0000000000
get_helper_proto kernel/bpf/verifier.c:11360 [inline]
check_helper_call+0x237/0x6a90 kernel/bpf/verifier.c:11380
do_check_insn kernel/bpf/verifier.c:19928 [inline]
do_check+0x8b35/0xe520 kernel/bpf/verifier.c:20097
do_check_common+0x1949/0x24f0 kernel/bpf/verifier.c:23264
do_check_main kernel/bpf/verifier.c:23347 [inline]
bpf_check+0x1746a/0x1d2d0 kernel/bpf/verifier.c:24707
bpf_prog_load+0x1318/0x1930 kernel/bpf/syscall.c:2979
__sys_bpf+0x528/0x870 kernel/bpf/syscall.c:6029
__do_sys_bpf kernel/bpf/syscall.c:6139 [inline]
__se_sys_bpf kernel/bpf/syscall.c:6137 [inline]
__x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6137
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe02278eec9
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:00007fe023542038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007fe0229e5fa0 RCX: 00007fe02278eec9
RDX: 0000000000000025 RSI: 0000200000002c80 RDI: 0000000000000005
RBP: 00007fe022811f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe0229e6038 R14: 00007fe0229e5fa0 R15: 00007ffe0ce425f8
----------------
Code disassembly (best guess):
0: cc int3
1: e8 d1 27 e8 09 call 0x9e827d7
6: 90 nop
7: 90 nop
8: 90 nop
9: 90 nop
a: 90 nop
b: 90 nop
c: 90 nop
d: 90 nop
e: 90 nop
f: 90 nop
10: 90 nop
11: 90 nop
12: 90 nop
13: 90 nop
14: 90 nop
15: 90 nop
16: 90 nop
17: 41 57 push %r15
19: 41 56 push %r14
1b: 53 push %rbx
1c: 66 90 xchg %ax,%ax
1e: e8 74 be ea 09 call 0x9eabe97
23: e8 af 27 35 00 call 0x3527d7
28: fb sti
29: 5b pop %rbx
* 2a: 41 5e pop %r14 <-- trapping instruction
2c: 41 5f pop %r15
2e: e9 d4 0c eb 09 jmp 0x9eb0d07
33: cc int3
34: f3 0f 1e fa endbr64
38: 49 rex.WB
39: be 00 00 00 00 mov $0x0,%esi
3e: 00 fc add %bh,%ah