From: Wei Liu <wei.liu@kernel.org>
To: Sasha Levin <sashal@kernel.org>
Cc: kys@microsoft.com, haiyangz@microsoft.com,
sthemmin@microsoft.com, wei.liu@kernel.org, tglx@linutronix.de,
mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com,
vkuznets@redhat.com, mikelley@microsoft.com,
linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@kernel.org
Subject: Re: [PATCH v2 1/2] x86/hyper-v: guard against cpu mask changes in hyperv_flush_tlb_others()
Date: Tue, 13 Oct 2020 09:25:25 +0000 [thread overview]
Message-ID: <20201013092525.4po4glgjn2vodytf@liuwe-devbox-debian-v2> (raw)
In-Reply-To: <20201005233739.2560641-1-sashal@kernel.org>
On Mon, Oct 05, 2020 at 07:37:38PM -0400, Sasha Levin wrote:
> cpumask can change underneath us, which is generally safe except when we
> call into hv_cpu_number_to_vp_number(): if cpumask ends up empty we pass
> num_cpu_possible() into hv_cpu_number_to_vp_number(), causing it to read
> garbage. As reported by KASAN:
>
> [ 83.504763] BUG: KASAN: slab-out-of-bounds in hyperv_flush_tlb_others (include/asm-generic/mshyperv.h:128 arch/x86/hyperv/mmu.c:112)
> [ 83.908636] Read of size 4 at addr ffff888267c01370 by task kworker/u8:2/106
> [ 84.196669] CPU: 0 PID: 106 Comm: kworker/u8:2 Tainted: G W 5.4.60 #1
> [ 84.196669] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS 090008 12/07/2018
> [ 84.196669] Workqueue: writeback wb_workfn (flush-8:0)
> [ 84.196669] Call Trace:
> [ 84.196669] dump_stack (lib/dump_stack.c:120)
> [ 84.196669] print_address_description.constprop.0 (mm/kasan/report.c:375)
> [ 84.196669] __kasan_report.cold (mm/kasan/report.c:507)
> [ 84.196669] kasan_report (arch/x86/include/asm/smap.h:71 mm/kasan/common.c:635)
> [ 84.196669] hyperv_flush_tlb_others (include/asm-generic/mshyperv.h:128 arch/x86/hyperv/mmu.c:112)
> [ 84.196669] flush_tlb_mm_range (arch/x86/include/asm/paravirt.h:68 arch/x86/mm/tlb.c:798)
> [ 84.196669] ptep_clear_flush (arch/x86/include/asm/tlbflush.h:586 mm/pgtable-generic.c:88)
>
What is the easiest way to reproduce this? Just enable KASAN in the
guest and run it normally? I want to have a chance to verify my earlier
reply.
Thanks,
Wei.
prev parent reply other threads:[~2020-10-13 9:25 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-05 23:37 [PATCH v2 1/2] x86/hyper-v: guard against cpu mask changes in hyperv_flush_tlb_others() Sasha Levin
2020-10-05 23:37 ` [PATCH v2 2/2] x86/hyperv: add a bounds check to hv_cpu_number_to_vp_number() Sasha Levin
2020-10-13 9:25 ` Wei Liu [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201013092525.4po4glgjn2vodytf@liuwe-devbox-debian-v2 \
--to=wei.liu@kernel.org \
--cc=bp@alien8.de \
--cc=haiyangz@microsoft.com \
--cc=hpa@zytor.com \
--cc=kys@microsoft.com \
--cc=linux-hyperv@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mikelley@microsoft.com \
--cc=mingo@redhat.com \
--cc=sashal@kernel.org \
--cc=stable@kernel.org \
--cc=sthemmin@microsoft.com \
--cc=tglx@linutronix.de \
--cc=vkuznets@redhat.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).