linux-kernel - Re: [syzbot] [kvmarm?] WARNING in pend_sync

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Message-ID: <861pqiaojt.wl-maz@kernel.org>
Date: Mon, 14 Jul 2025 14:29:26 +0100
From: Marc Zyngier <maz@...nel.org>
To: syzbot <syzbot+4e09b1432de3774b86ae@...kaller.appspotmail.com>
Cc: catalin.marinas@....com,
	joey.gouly@....com,
	kvmarm@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	oliver.upton@...ux.dev,
	suzuki.poulose@....com,
	syzkaller-bugs@...glegroups.com,
	will@...nel.org,
	yuzenghui@...wei.com
Subject: Re: [syzbot] [kvmarm?] WARNING in pend_sync_exception

On Sun, 13 Jul 2025 02:45:31 +0100,
syzbot <syzbot+4e09b1432de3774b86ae@...kaller.appspotmail.com> wrote:
> 
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    15724a984643 Merge branch 'kvm-arm64/doublefault2' into kv..
> 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=13e26a8c580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=82bd3cd421993314
> dashboard link: https://syzkaller.appspot.com/bug?extid=4e09b1432de3774b86ae
> 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=17137582580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17e26a8c580000
> 
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/fa3fbcfdac58/non_bootable_disk-15724a98.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/ec0f03d375a1/vmlinux-15724a98.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/a36232f8c6dd/Image-15724a98.gz.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+4e09b1432de3774b86ae@...kaller.appspotmail.com
> 
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 3595 at arch/arm64/kvm/inject_fault.c:63 pend_sync_exception+0x198/0x5ac arch/arm64/kvm/inject_fault.c:63
> Modules linked in:
> CPU: 0 UID: 0 PID: 3595 Comm: syz.2.16 Not tainted 6.16.0-rc3-syzkaller-g15724a984643 #0 PREEMPT 
> Hardware name: linux,dummy-virt (DT)
> pstate: 81402009 (Nzcv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
> pc : pend_sync_exception+0x198/0x5ac arch/arm64/kvm/inject_fault.c:63
> lr : pend_sync_exception+0x198/0x5ac arch/arm64/kvm/inject_fault.c:63
> sp : ffff80008e7378c0
> x29: ffff80008e7378c0 x28: 0000000000000063 x27: 63f000001d7702a8
> x26: 0000000000000063 x25: 0000000000000000 x24: 0000000000000000
> x23: 0000000000000000 x22: 0000000000000063 x21: 63f000001d770e81
> x20: 0000000000000007 x19: efff800000000000 x18: 0000000000000000
> x17: 0000000000000041 x16: ffff800080011d9c x15: 00000000200000c0
> x14: ffffffffffffffff x13: 0000000000000028 x12: 00000000000000cc
> x11: ccf000001d756de4 x10: 0000000000ff0100 x9 : 0000000000000000
> x8 : ccf000001d755880 x7 : ffff800080b08704 x6 : ffff80008e737a88
> x5 : ffff80008e737a88 x4 : 0000000000000001 x3 : ffff8000801a2e80
> x2 : 0000000000000000 x1 : 0000000000000002 x0 : 0000000000000000
> Call trace:
>  pend_sync_exception+0x198/0x5ac arch/arm64/kvm/inject_fault.c:63 (P)
>  inject_abt64 arch/arm64/kvm/inject_fault.c:115 [inline]
>  __kvm_inject_sea+0x268/0x96c arch/arm64/kvm/inject_fault.c:207
>  kvm_inject_sea+0x98/0x72c arch/arm64/kvm/inject_fault.c:229
>  kvm_inject_sea_dabt arch/arm64/include/asm/kvm_emulate.h:54 [inline]
>  __kvm_arm_vcpu_set_events+0x134/0x238 arch/arm64/kvm/guest.c:847
>  kvm_arm_vcpu_set_events arch/arm64/kvm/arm.c:1698 [inline]
>  kvm_arch_vcpu_ioctl+0xed8/0x16b0 arch/arm64/kvm/arm.c:1810
>  kvm_vcpu_ioctl+0x5c4/0xc2c virt/kvm/kvm_main.c:4632
>  vfs_ioctl fs/ioctl.c:51 [inline]
>  __do_sys_ioctl fs/ioctl.c:907 [inline]
>  __se_sys_ioctl fs/ioctl.c:893 [inline]
>  __arm64_sys_ioctl+0x18c/0x244 fs/ioctl.c:893
>  __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
>  invoke_syscall+0x90/0x2b4 arch/arm64/kernel/syscall.c:49
>  el0_svc_common+0x180/0x2f4 arch/arm64/kernel/syscall.c:132
>  do_el0_svc+0x58/0x74 arch/arm64/kernel/syscall.c:151
>  el0_svc+0x58/0x160 arch/arm64/kernel/entry-common.c:767
>  el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786
>  el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
> irq event stamp: 2626
> hardirqs last  enabled at (2625): [<ffff80008653cb88>] __raw_read_unlock_irqrestore include/linux/rwlock_api_smp.h:241 [inline]
> hardirqs last  enabled at (2625): [<ffff80008653cb88>] _raw_read_unlock_irqrestore+0x44/0xbc kernel/locking/spinlock.c:268
> hardirqs last disabled at (2626): [<ffff800086517e08>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:511
> softirqs last  enabled at (2576): [<ffff8000800c988c>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
> softirqs last disabled at (2574): [<ffff8000800c9858>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
> ---[ end trace 0000000000000000 ]---

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git kvm-arm64/df-2-fixes

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