------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 0 PID: 5940 at lib/refcount.c:28 refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28 Modules linked in: CPU: 0 UID: 0 PID: 5940 Comm: syz-executor Not tainted 6.13.0-rc6-syzkaller-00006-g5428dc1906dd #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 e8 97 00 fd 84 db 0f 85 66 ff ff ff e8 3b 9d 00 fd c6 05 b4 e1 6c 0b 01 90 48 c7 c7 80 25 b1 8b e8 a7 60 c1 fc 90 <0f> 0b 90 90 e9 43 ff ff ff e8 18 9d 00 fd 0f b6 1d 8f e1 6c 0b 31 RSP: 0018:ffffc90000007be8 EFLAGS: 00010082 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff815a1789 RDX: ffff8880285a4880 RSI: ffffffff815a1796 RDI: 0000000000000001 RBP: ffff888069a5a448 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: ffff888069a5a448 R13: ffff888020c6d000 R14: 0000000000000015 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88802b400000(0063) knlGS:0000000058123440 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 00000000f7fc55c0 CR3: 000000006344c000 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+0x61/0xe0 arch/x86/kernel/irq.c:278 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693 RIP: 0010:handle_softirqs+0x1da/0x8f0 kernel/softirq.c:547 Code: 89 44 24 18 48 89 6c 24 10 48 c7 c7 00 71 4b 8b e8 db 55 be 09 65 66 c7 05 f9 ce a7 7e 00 00 e8 0c e3 44 00 fb bb ff ff ff ff <49> c7 c6 c0 b0 a0 8d 41 0f bc dc 83 c3 01 0f 85 a4 00 00 00 e9 b1 RSP: 0018:ffffc90000007f28 EFLAGS: 00000206 RAX: 000000000053efca RBX: 00000000ffffffff RCX: 1ffffffff20394e1 RDX: 0000000000000000 RSI: ffffffff8b4cd300 RDI: ffffffff8bb17040 RBP: ffff8880285a4880 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff901cea57 R11: 0000000000000000 R12: 0000000000000200 R13: 000000000000000a R14: 0000000000000001 R15: 0000000000000000 __do_softirq kernel/softirq.c:595 [inline] invoke_softirq kernel/softirq.c:435 [inline] __irq_exit_rcu+0x109/0x170 kernel/softirq.c:662 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 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 06 70 59 f6 48 89 df e8 4e ef 59 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 65 df 4a f6 65 8b 05 86 02 e7 74 85 c0 74 16 5b RSP: 0018:ffffc900039d7c08 EFLAGS: 00000246 RAX: 0000000000000006 RBX: ffff88806d558a00 RCX: 1ffffffff20394e1 RDX: 0000000000000000 RSI: ffffffff8b4cd300 RDI: ffffffff8bb17040 RBP: 0000000000000246 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff901cea57 R11: 0000000000000002 R12: 1ffff9200073af8a R13: ffff88806d558000 R14: ffff88806d5582b0 R15: ffffffff8d81fad8 task_rq_unlock kernel/sched/sched.h:1797 [inline] wake_up_new_task+0x87f/0xd40 kernel/sched/core.c:4884 kernel_clone+0x59b/0x960 kernel/fork.c:2837 __do_compat_sys_ia32_clone+0xb7/0x100 arch/x86/kernel/sys_ia32.c:254 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7fd7579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000ffac43ec EFLAGS: 00000292 ORIG_RAX: 0000000000000078 RAX: ffffffffffffffda RBX: 0000000001200011 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000581234a8 RBP: 00000000f7463ff4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess): 0: 89 44 24 18 mov %eax,0x18(%rsp) 4: 48 89 6c 24 10 mov %rbp,0x10(%rsp) 9: 48 c7 c7 00 71 4b 8b mov $0xffffffff8b4b7100,%rdi 10: e8 db 55 be 09 call 0x9be55f0 15: 65 66 c7 05 f9 ce a7 movw $0x0,%gs:0x7ea7cef9(%rip) # 0x7ea7cf18 1c: 7e 00 00 1f: e8 0c e3 44 00 call 0x44e330 24: fb sti 25: bb ff ff ff ff mov $0xffffffff,%ebx * 2a: 49 c7 c6 c0 b0 a0 8d mov $0xffffffff8da0b0c0,%r14 <-- trapping instruction 31: 41 0f bc dc bsf %r12d,%ebx 35: 83 c3 01 add $0x1,%ebx 38: 0f 85 a4 00 00 00 jne 0xe2 3e: e9 .byte 0xe9 3f: b1 .byte 0xb1