------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 3 PID: 8755 at lib/refcount.c:28 refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28 Modules linked in: CPU: 3 UID: 0 PID: 8755 Comm: modprobe Not tainted 6.13.0-rc5-syzkaller-00004-gccb98ccef0e5 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28 Code: ff 89 de e8 38 04 fa fc 84 db 0f 85 66 ff ff ff e8 4b 02 fa fc c6 05 cb d1 a7 0b 01 90 48 c7 c7 e0 9a d1 8b e8 b7 3b ba fc 90 <0f> 0b 90 90 e9 43 ff ff ff e8 28 02 fa fc 0f b6 1d a6 d1 a7 0b 31 RSP: 0018:ffffc90000708d90 EFLAGS: 00010082 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff815a5139 RDX: ffff8880247da440 RSI: ffffffff815a5146 RDI: 0000000000000001 RBP: ffff88802adf7658 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000003 R12: ffff88802adf7658 R13: ffff888027a47000 R14: 0000000000000014 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88806a900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fbf744daba8 CR3: 000000005168a000 CR4: 0000000000352ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __refcount_sub_and_test include/linux/refcount.h:275 [inline] __refcount_dec_and_test include/linux/refcount.h:307 [inline] refcount_dec_and_test include/linux/refcount.h:325 [inline] p9_req_put+0x1ec/0x250 net/9p/client.c:404 req_done+0x1e7/0x2f0 net/9p/trans_virtio.c:147 vring_interrupt drivers/virtio/virtio_ring.c:2715 [inline] vring_interrupt+0x31b/0x400 drivers/virtio/virtio_ring.c:2690 __handle_irq_event_percpu+0x229/0x7d0 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x263/0xd10 kernel/irq/chip.c:831 generic_handle_irq_desc include/linux/irqdesc.h:173 [inline] handle_irq arch/x86/kernel/irq.c:247 [inline] call_irq_handler arch/x86/kernel/irq.c:259 [inline] __common_interrupt+0xdf/0x250 arch/x86/kernel/irq.c:285 common_interrupt+0xba/0xe0 arch/x86/kernel/irq.c:278 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194 Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 56 71 4a f6 48 89 df e8 ae f0 4a f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 95 d5 3b f6 65 8b 05 f6 90 d7 74 85 c0 74 16 5b RSP: 0018:ffffc9000420f228 EFLAGS: 00000246 RAX: 0000000000000002 RBX: ffffffff9a9bb728 RCX: 1ffffffff20bde71 RDX: 0000000000000000 RSI: ffffffff8b6cd9e0 RDI: ffffffff8bd1ede0 RBP: 0000000000000206 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff905f36d7 R11: 0000000000000003 R12: 0000000000000158 R13: 0000000000000001 R14: dffffc0000000000 R15: 0000000000000206 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] avc_reclaim_node security/selinux/avc.c:482 [inline] avc_alloc_node+0x365/0x5a0 security/selinux/avc.c:501 avc_insert security/selinux/avc.c:612 [inline] avc_compute_av+0xfd/0x5c0 security/selinux/avc.c:987 avc_perm_nonode+0xaa/0x170 security/selinux/avc.c:1110 avc_has_perm_noaudit+0x2d2/0x3a0 security/selinux/avc.c:1153 cred_has_capability.isra.0+0x170/0x2f0 security/selinux/hooks.c:1650 security_capable+0xd3/0x260 security/security.c:1142 has_ns_capability_noaudit+0xb7/0x2a0 kernel/capability.c:327 ima_match_rules security/integrity/ima/ima_policy.c:609 [inline] ima_match_policy+0x118b/0x22e0 security/integrity/ima/ima_policy.c:760 ima_get_action+0x82/0xb0 security/integrity/ima/ima_api.c:199 process_measurement+0x2e1/0x2370 security/integrity/ima/ima_main.c:235 ima_file_check+0xbd/0x100 security/integrity/ima/ima_main.c:572 security_file_post_open+0x8e/0x210 security/security.c:3121 do_open fs/namei.c:3830 [inline] path_openat+0x1419/0x2d60 fs/namei.c:3987 do_filp_open+0x20c/0x470 fs/namei.c:4014 do_sys_openat2+0x17a/0x1e0 fs/open.c:1402 do_sys_open fs/open.c:1417 [inline] __do_sys_openat fs/open.c:1433 [inline] __se_sys_openat fs/open.c:1428 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1428 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbf74787a46 Code: 10 00 00 00 44 8b 54 24 e0 48 89 44 24 c0 48 8d 44 24 d0 48 89 44 24 c8 44 89 c2 4c 89 ce bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 76 0c f7 d8 89 05 0a 48 01 00 48 83 c8 ff c3 31 RSP: 002b:00007ffec255c5b8 EFLAGS: 00000287 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007ffec255c818 RCX: 00007fbf74787a46 RDX: 0000000000080000 RSI: 00007ffec255c630 RDI: 00000000ffffff9c RBP: 00007ffec255c620 R08: 0000000000080000 R09: 00007ffec255c630 R10: 0000000000000000 R11: 0000000000000287 R12: 00007ffec255c630 R13: 0000000000000012 R14: 00007ffec255c7ff R15: 00000000ffffffff ---------------- Code disassembly (best guess): 0: f5 cmc 1: 53 push %rbx 2: 48 8b 74 24 10 mov 0x10(%rsp),%rsi 7: 48 89 fb mov %rdi,%rbx a: 48 83 c7 18 add $0x18,%rdi e: e8 56 71 4a f6 call 0xf64a7169 13: 48 89 df mov %rbx,%rdi 16: e8 ae f0 4a f6 call 0xf64af0c9 1b: f7 c5 00 02 00 00 test $0x200,%ebp 21: 75 23 jne 0x46 23: 9c pushf 24: 58 pop %rax 25: f6 c4 02 test $0x2,%ah 28: 75 37 jne 0x61 * 2a: bf 01 00 00 00 mov $0x1,%edi <-- trapping instruction 2f: e8 95 d5 3b f6 call 0xf63bd5c9 34: 65 8b 05 f6 90 d7 74 mov %gs:0x74d790f6(%rip),%eax # 0x74d79131 3b: 85 c0 test %eax,%eax 3d: 74 16 je 0x55 3f: 5b pop %rbx