------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 1 PID: 7583 at lib/refcount.c:28 refcount_warn_saturate+0x11a/0x1d0 lib/refcount.c:28
Modules linked in:
CPU: 1 UID: 0 PID: 7583 Comm: syz.4.526 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: 00 b2 bf 8b e8 f7 19 f3 fc 90 0f 0b 90 90 eb d7 e8 9b fb 2f fd c6 05 68 a1 f8 0a 01 90 48 c7 c7 60 b2 bf 8b e8 d7 19 f3 fc 90 <0f> 0b 90 90 eb b7 e8 7b fb 2f fd c6 05 45 a1 f8 0a 01 90 48 c7 c7
RSP: 0018:ffffc90000a08b88 EFLAGS: 00010246
RAX: 9347d7e8680cbf00 RBX: 0000000000000003 RCX: ffff8880670b9e40
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffffc90000a08c90 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1bfa244 R12: 1ffff92000141178
R13: ffff8880794bf9b8 R14: ffff8880794bf820 R15: 0000000000000001
FS: 00007f563e1596c0(0000) GS:ffff888125e27000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000007e56a000 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:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:perf_trace_buf_alloc+0x0/0x2a0 kernel/trace/trace_event_perf.c:399
Code: 55 81 09 cc e8 41 65 f6 ff 43 80 7c 25 00 00 75 ce eb d4 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 55 41 57 41 56 41 55 41 54 53 50 49 89 d7 49 89 f6 89
RSP: 0018:ffffc9000c0af798 EFLAGS: 00000203
RAX: 1ffffd1ffff20012 RBX: ffffe8ffff900090 RCX: ffffe8ffff900090
RDX: ffffc9000c0af820 RSI: ffffc9000c0af800 RDI: 000000000000002c
RBP: ffffc9000c0af898 R08: 0000000000000000 R09: ffffffff81ce2bd6
R10: ffffc9000c0af548 R11: fffff52001815eab R12: 1ffff92001815efc
R13: 000000000000000d R14: 000000000000002c R15: dffffc0000000000
do_perf_trace_lock include/trace/events/lock.h:50 [inline]
perf_trace_lock+0x18d/0x3b0 include/trace/events/lock.h:50
__do_trace_lock_release include/trace/events/lock.h:69 [inline]
trace_lock_release include/trace/events/lock.h:69 [inline]
lock_release+0x3b2/0x3e0 kernel/locking/lockdep.c:5879
rcu_lock_release include/linux/rcupdate.h:341 [inline]
rcu_read_unlock include/linux/rcupdate.h:871 [inline]
is_bpf_text_address+0x28d/0x2b0 kernel/bpf/core.c:746
kernel_text_address+0xa5/0xe0 kernel/extable.c:125
__kernel_text_address+0xd/0x40 kernel/extable.c:79
unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:369
arch_stack_walk+0xfc/0x150 arch/x86/kernel/stacktrace.c:26
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:56 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
unpoison_slab_object mm/kasan/common.c:342 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:368
kasan_slab_alloc include/linux/kasan.h:252 [inline]
slab_post_alloc_hook mm/slub.c:4946 [inline]
slab_alloc_node mm/slub.c:5245 [inline]
kmem_cache_alloc_lru_noprof+0x35d/0x6d0 mm/slub.c:5264
sock_alloc_inode+0x28/0xc0 net/socket.c:322
alloc_inode+0x6a/0x1b0 fs/inode.c:346
new_inode_pseudo include/linux/fs.h:3394 [inline]
sock_alloc net/socket.c:637 [inline]
__sock_create+0x12d/0x9f0 net/socket.c:1569
sock_create net/socket.c:1663 [inline]
__sys_socket_create net/socket.c:1700 [inline]
__sys_socket+0xd7/0x1b0 net/socket.c:1747
__do_sys_socket net/socket.c:1761 [inline]
__se_sys_socket net/socket.c:1759 [inline]
__x64_sys_socket+0x7a/0x90 net/socket.c:1759
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f563d38eec9
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:00007f563e159038 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 00007f563d5e5fa0 RCX: 00007f563d38eec9
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 000000000000001e
RBP: 00007f563d411f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f563d5e6038 R14: 00007f563d5e5fa0 R15: 00007ffc63379758
----------------
Code disassembly (best guess):
0: 55 push %rbp
1: 81 09 cc e8 41 65 orl $0x6541e8cc,(%rcx)
7: f6 ff idiv %bh
9: 43 80 7c 25 00 00 cmpb $0x0,0x0(%r13,%r12,1)
f: 75 ce jne 0xffffffdf
11: eb d4 jmp 0xffffffe7
13: 0f 1f 80 00 00 00 00 nopl 0x0(%rax)
1a: 90 nop
1b: 90 nop
1c: 90 nop
1d: 90 nop
1e: 90 nop
1f: 90 nop
20: 90 nop
21: 90 nop
22: 90 nop
23: 90 nop
24: 90 nop
25: 90 nop
26: 90 nop
27: 90 nop
28: 90 nop
29: 90 nop
* 2a: f3 0f 1e fa endbr64 <-- trapping instruction
2e: 55 push %rbp
2f: 41 57 push %r15
31: 41 56 push %r14
33: 41 55 push %r13
35: 41 54 push %r12
37: 53 push %rbx
38: 50 push %rax
39: 49 89 d7 mov %rdx,%r15
3c: 49 89 f6 mov %rsi,%r14
3f: 89 .byte 0x89