From: Paolo Bonzini <pbonzini@redhat.com>
To: Sasha Levin <sashal@kernel.org>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Wanpeng Li <wanpengli@tencent.com>, kvm@vger.kernel.org
Subject: Re: [PATCH AUTOSEL 5.4 02/11] KVM: Fix lockdep false negative during host resume
Date: Tue, 1 Mar 2022 21:22:18 +0100 [thread overview]
Message-ID: <3fee5315-e55d-278c-e522-d0e6fb2cadd0@redhat.com> (raw)
In-Reply-To: <20220301201951.19066-2-sashal@kernel.org>
On 3/1/22 21:19, Sasha Levin wrote:
> From: Wanpeng Li <wanpengli@tencent.com>
>
> [ Upstream commit 4cb9a998b1ce25fad74a82f5a5c45a4ef40de337 ]
>
> I saw the below splatting after the host suspended and resumed.
>
> WARNING: CPU: 0 PID: 2943 at kvm/arch/x86/kvm/../../../virt/kvm/kvm_main.c:5531 kvm_resume+0x2c/0x30 [kvm]
> CPU: 0 PID: 2943 Comm: step_after_susp Tainted: G W IOE 5.17.0-rc3+ #4
> RIP: 0010:kvm_resume+0x2c/0x30 [kvm]
> Call Trace:
> <TASK>
> syscore_resume+0x90/0x340
> suspend_devices_and_enter+0xaee/0xe90
> pm_suspend.cold+0x36b/0x3c2
> state_store+0x82/0xf0
> kernfs_fop_write_iter+0x1b6/0x260
> new_sync_write+0x258/0x370
> vfs_write+0x33f/0x510
> ksys_write+0xc9/0x160
> do_syscall_64+0x3b/0xc0
> entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> lockdep_is_held() can return -1 when lockdep is disabled which triggers
> this warning. Let's use lockdep_assert_not_held() which can detect
> incorrect calls while holding a lock and it also avoids false negatives
> when lockdep is disabled.
>
> Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
> Message-Id: <1644920142-81249-1-git-send-email-wanpengli@tencent.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
> virt/kvm/kvm_main.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index f31976010622f..adda0c6672b56 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -4427,9 +4427,7 @@ static int kvm_suspend(void)
> static void kvm_resume(void)
> {
> if (kvm_usage_count) {
> -#ifdef CONFIG_LOCKDEP
> - WARN_ON(lockdep_is_held(&kvm_count_lock));
> -#endif
> + lockdep_assert_not_held(&kvm_count_lock);
> hardware_enable_nolock(NULL);
> }
> }
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
next prev parent reply other threads:[~2022-03-01 20:24 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-01 20:19 [PATCH AUTOSEL 5.4 01/11] selftests/bpf: Add test for bpf_timer overwriting crash Sasha Levin
2022-03-01 20:19 ` [PATCH AUTOSEL 5.4 02/11] KVM: Fix lockdep false negative during host resume Sasha Levin
2022-03-01 20:22 ` Paolo Bonzini [this message]
2022-03-01 20:19 ` [PATCH AUTOSEL 5.4 03/11] net-sysfs: add check for netdevice being present to speed_show Sasha Levin
2022-03-01 20:19 ` [PATCH AUTOSEL 5.4 04/11] sr9700: sanity check for packet length Sasha Levin
2022-03-01 20:19 ` [PATCH AUTOSEL 5.4 05/11] gpio: Return EPROBE_DEFER if gc->to_irq is NULL Sasha Levin
2022-03-01 20:19 ` [PATCH AUTOSEL 5.4 06/11] Revert "xen-netback: remove 'hotplug-status' once it has served its purpose" Sasha Levin
2022-03-01 20:19 ` [PATCH AUTOSEL 5.4 07/11] Revert "xen-netback: Check for hotplug-status existence before watching" Sasha Levin
2022-03-01 20:19 ` [PATCH AUTOSEL 5.4 08/11] ipv6: prevent a possible race condition with lifetimes Sasha Levin
2022-03-01 20:19 ` [PATCH AUTOSEL 5.4 09/11] tracing: Ensure trace buffer is at least 4096 bytes large Sasha Levin
2022-03-01 20:19 ` [PATCH AUTOSEL 5.4 10/11] selftest/vm: fix map_fixed_noreplace test failure Sasha Levin
2022-03-01 20:19 ` [PATCH AUTOSEL 5.4 11/11] selftests/memfd: clean up mapping in mfd_fail_write Sasha Levin
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