Re: [syzbot] [kvmarm?] [kvm?] WARNING: locking bug in vgic_put_irq

[Oliver Upton <oliver.upton@linux.dev>]

On Mon, Aug 25, 2025 at 02:08:41PM -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    7b8346bd9fce KVM: arm64: Don't attempt vLPI mappings when ..
> git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git next
> console output: https://syzkaller.appspot.com/x/log.txt?x=17b4e862580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=7c53d3478750eda0
> dashboard link: https://syzkaller.appspot.com/bug?extid=cef594105ac7e60c6d93
> compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
> userspace arch: arm64
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15860634580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1074e862580000
> 
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/fa3fbcfdac58/non_bootable_disk-7b8346bd.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/74f545807499/vmlinux-7b8346bd.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/d83062566dc7/Image-7b8346bd.gz.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+cef594105ac7e60c6d93@syzkaller.appspotmail.com
> 
> =============================
> [ BUG: Invalid wait context ]
> 6.16.0-rc3-syzkaller-g7b8346bd9fce #0 Not tainted
> -----------------------------
> syz.0.29/3743 is trying to lock:
> a3ff80008e2e9e18 (&xa->xa_lock#20){....}-{3:3}, at: vgic_put_irq+0xb4/0x190 arch/arm64/kvm/vgic/vgic.c:137
> other info that might help us debug this:
> context-{5:5}
> 3 locks held by syz.0.29/3743:
>  #0: a3ff80008e2e90a8 (&kvm->slots_lock){+.+.}-{4:4}, at: kvm_vgic_destroy+0x50/0x624 arch/arm64/kvm/vgic/vgic-init.c:499
>  #1: a3ff80008e2e9fa0 (&kvm->arch.config_lock){+.+.}-{4:4}, at: kvm_vgic_destroy+0x5c/0x624 arch/arm64/kvm/vgic/vgic-init.c:500
>  #2: 58f0000021be1428 (&vgic_cpu->ap_list_lock){....}-{2:2}, at: vgic_flush_pending_lpis+0x3c/0x31c arch/arm64/kvm/vgic/vgic.c:150
> stack backtrace:
> CPU: 0 UID: 0 PID: 3743 Comm: syz.0.29 Not tainted 6.16.0-rc3-syzkaller-g7b8346bd9fce #0 PREEMPT 
> Hardware name: linux,dummy-virt (DT)
> Call trace:
>  show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:466 (C)
>  __dump_stack+0x30/0x40 lib/dump_stack.c:94
>  dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
>  dump_stack+0x1c/0x28 lib/dump_stack.c:129
>  print_lock_invalid_wait_context kernel/locking/lockdep.c:4833 [inline]
>  check_wait_context kernel/locking/lockdep.c:4905 [inline]
>  __lock_acquire+0x978/0x299c kernel/locking/lockdep.c:5190
>  lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5871
>  __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
>  _raw_spin_lock_irqsave+0x5c/0x7c kernel/locking/spinlock.c:162
>  vgic_put_irq+0xb4/0x190 arch/arm64/kvm/vgic/vgic.c:137
>  vgic_flush_pending_lpis+0x24c/0x31c arch/arm64/kvm/vgic/vgic.c:158
>  __kvm_vgic_vcpu_destroy+0x44/0x500 arch/arm64/kvm/vgic/vgic-init.c:455
>  kvm_vgic_destroy+0x100/0x624 arch/arm64/kvm/vgic/vgic-init.c:505
>  kvm_arch_destroy_vm+0x80/0x138 arch/arm64/kvm/arm.c:244
>  kvm_destroy_vm virt/kvm/kvm_main.c:1308 [inline]
>  kvm_put_kvm+0x800/0xff8 virt/kvm/kvm_main.c:1344
>  kvm_vm_release+0x58/0x78 virt/kvm/kvm_main.c:1367
>  __fput+0x4ac/0x980 fs/file_table.c:465
>  ____fput+0x20/0x58 fs/file_table.c:493
>  task_work_run+0x1bc/0x254 kernel/task_work.c:227
>  resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
>  do_notify_resume+0x1b4/0x270 arch/arm64/kernel/entry-common.c:151
>  exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline]
>  exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline]
>  el0_svc+0xb4/0x160 arch/arm64/kernel/entry-common.c:768
>  el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786
>  el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
> 
> 
> ---
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#syz test git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git fixes