------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: lib/refcount.c:28 at refcount_warn_saturate+0xb2/0x110 lib/refcount.c:28, CPU#1: syz.0.637/9095
Modules linked in:
CPU: 1 UID: 0 PID: 9095 Comm: syz.0.637 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:refcount_warn_saturate+0xb2/0x110 lib/refcount.c:28
Code: b4 48 6d 0b 67 48 0f b9 3a eb 4a e8 58 7a 16 fd 48 8d 3d b1 48 6d 0b 67 48 0f b9 3a eb 37 e8 45 7a 16 fd 48 8d 3d ae 48 6d 0b <67> 48 0f b9 3a eb 24 e8 32 7a 16 fd 48 8d 3d ab 48 6d 0b 67 48 0f
RSP: 0018:ffffc90000a08c88 EFLAGS: 00010246
RAX: ffffffff84af27eb RBX: 0000000000000003 RCX: ffff888029aa5b80
RDX: 0000000000000100 RSI: ffffffff8ef01e60 RDI: ffffffff901c70a0
RBP: ffffc90000a08d90 R08: ffff888029aa5b80 R09: 0000000000000005
R10: 0000000000000004 R11: 0000000000000100 R12: 0000000000000001
R13: 00000000fffffcf8 R14: ffff88807af36020 R15: ffff88807af36168
FS: 00007efe30e8a6c0(0000) GS:ffff88812555d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007facde9e9f00 CR3: 0000000063f62000 CR4: 00000000003526f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff1 DR7: 00000000000f0602
Call Trace:
call_timer_fn+0x192/0x640 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2373 [inline]
__run_timer_base+0x652/0x8b0 kernel/time/timer.c:2385
run_timer_base kernel/time/timer.c:2394 [inline]
run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2404
handle_softirqs+0x22a/0x870 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:preempt_schedule_irq+0x48/0xa0 kernel/sched/core.c:7238
Code: 49 be 00 00 00 00 00 fc ff df eb 09 48 f7 03 10 00 00 00 74 53 bf 01 00 00 00 e8 e3 07 e4 f5 e8 4e a6 1d f6 fb bf 01 00 00 00 c3 a6 ff ff 9c 58 fa a9 00 02 00 00 74 05 e8 24 a8 1d f6 bf 01
RSP: 0018:ffffc90003336f00 EFLAGS: 00000202
RAX: 00000000000066d3 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8def8cb4 RDI: 0000000000000001
RBP: 0000000000000000 R08: ffffffff9011b2b7 R09: 1ffffffff2023656
R10: dffffc0000000000 R11: fffffbfff2023657 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 0000000000000000
irqentry_exit+0x599/0x620 kernel/entry/common.c:239
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__rcu_read_unlock+0x7e/0xe0 kernel/rcu/tree_plugin.h:438
Code: 00 75 27 43 0f b6 04 3c 84 c0 75 41 8b 03 3d 00 00 00 40 73 0f 5b 41 5c 41 5d 41 5e 41 5f e9 09 2d 06 0a cc 90 0f 0b 90 eb eb 6d 00 00 00 eb d2 89 d9 80 e1 07 80 c1 03 38 c1 7c a5 49 89 fe
RSP: 0018:ffffc90003337020 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffff888029aa6044 RCX: 0000000000000046
RDX: 0000000000000000 RSI: ffffffff8e1699c5 RDI: ffff888029aa5b80
RBP: 0000000000000000 R08: ffffffff81d54aa6 R09: ffffffff8e75e5e0
R10: ffffc90003337138 R11: ffffffff81b0c390 R12: 1ffff11005354c08
R13: dffffc0000000000 R14: ffff888029aa6048 R15: dffffc0000000000
rcu_read_unlock include/linux/rcupdate.h:883 [inline]
is_bpf_text_address+0x292/0x2b0 kernel/bpf/core.c:750
kernel_text_address+0xa5/0xe0 kernel/extable.c:125
__kernel_text_address+0xd/0x30 kernel/extable.c:79
unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:385
arch_stack_walk+0xfb/0x150 arch/x86/kernel/stacktrace.c:26
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__do_kmalloc_node mm/slub.c:5260 [inline]
__kvmalloc_node_noprof+0x528/0x8a0 mm/slub.c:6752
compute_scc+0x9de/0xab0 kernel/bpf/verifier.c:25912
bpf_check+0x5ecd/0x1ce00 kernel/bpf/verifier.c:26061
bpf_prog_load+0x1484/0x1ae0 kernel/bpf/syscall.c:3089
__sys_bpf+0x618/0x950 kernel/bpf/syscall.c:6228
__do_sys_bpf kernel/bpf/syscall.c:6341 [inline]
__se_sys_bpf kernel/bpf/syscall.c:6339 [inline]
__x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6339
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7efe2ff9c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007efe30e8a028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007efe30215fa0 RCX: 00007efe2ff9c819
RDX: 0000000000000094 RSI: 0000200000000040 RDI: 0000000000000005
RBP: 00007efe30032c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007efe30216038 R14: 00007efe30215fa0 R15: 00007ffc7d99e988
----------------
Code disassembly (best guess):
0: b4 48 mov $0x48,%ah
2: 6d insl (%dx),%es:(%rdi)
3: 0b 67 48 or 0x48(%rdi),%esp
6: 0f b9 3a ud1 (%rdx),%edi
9: eb 4a jmp 0x55
b: e8 58 7a 16 fd call 0xfd167a68
10: 48 8d 3d b1 48 6d 0b lea 0xb6d48b1(%rip),%rdi # 0xb6d48c8
17: 67 48 0f b9 3a ud1 (%edx),%rdi
1c: eb 37 jmp 0x55
1e: e8 45 7a 16 fd call 0xfd167a68
23: 48 8d 3d ae 48 6d 0b lea 0xb6d48ae(%rip),%rdi # 0xb6d48d8
* 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction
2f: eb 24 jmp 0x55
31: e8 32 7a 16 fd call 0xfd167a68
36: 48 8d 3d ab 48 6d 0b lea 0xb6d48ab(%rip),%rdi # 0xb6d48e8
3d: 67 addr32
3e: 48 rex.W
3f: 0f .byte 0xf