From: Sean Christopherson <seanjc@google.com>
To: xingwei lee <xrivendell7@gmail.com>
Cc: linux-kernel@vger.kernel.org, dave.hansen@linux.intel.com,
bp@alien8.de, hpa@zytor.com, kvm@vger.kernel.org,
mingo@redhat.com, pbonzini@redhat.com,
Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org
Subject: Re: KMSAN: uninit-value in em_ret_far
Date: Tue, 2 Jan 2024 15:09:22 -0800 [thread overview]
Message-ID: <ZZSXotY3NRbki_hW@google.com> (raw)
In-Reply-To: <CABOYnLwfWmOUfP-uW9ALCxEXbzaSGVZn6GeEyfvPr-R-XdmrSQ@mail.gmail.com>
On Mon, Dec 25, 2023, xingwei lee wrote:
> Hello I found a bug in latest upstream 6.7-rc7 titled "KMSAN:
> uninit-value in em_ret_far” and maybe is realted with kvm.
>
> If you fix this issue, please add the following tag to the commit:
> Reported-by: xingwei lee <xrivendell7@gmail.com>
>
> kernel: mainline 861deac3b092f37b2c5e6871732f3e11486f7082
> kernel config: https://syzkaller.appspot.com/text?tag=KernelConfig&x=4a65fa9f077ead01
> with KMSAN enabled
> compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> run the repro.c for about 3minus and it crashed!
>
> TITLE: KMSAN: uninit-value in em_ret_far
> =====================================================
> BUG: KMSAN: uninit-value in emulator_recalc_and_set_mode
> arch/x86/kvm/emulate.c:797 [inline]
> BUG: KMSAN: uninit-value in assign_eip_far arch/x86/kvm/emulate.c:833 [inline]
> BUG: KMSAN: uninit-value in em_ret_far+0x348/0x350 arch/x86/kvm/emulate.c:2258
> emulator_recalc_and_set_mode arch/x86/kvm/emulate.c:797 [inline]
> assign_eip_far arch/x86/kvm/emulate.c:833 [inline]
This is a known issue[1]. It's effectively a false positive, even though there
is technically uninitialized data in scope. The proposed fix[2] from Julian
should resolve this (the patch is on my radar for 6.9).
[1] https://lore.kernel.org/all/9362077ac7f24ec684d338543e269e83aee7c897.camel@cyberus-technology.de
[2] https://lore.kernel.org/all/20231009092054.556935-1-julian.stecklina@cyberus-technology.de
prev parent reply other threads:[~2024-01-02 23:09 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-25 11:23 KMSAN: uninit-value in em_ret_far xingwei lee
2024-01-02 23:09 ` Sean Christopherson [this message]
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