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Date:   Thu, 9 Jun 2022 12:43:39 +0200
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Subject: Re: [PATCH V3 0/7] x86/entry: Convert error_entry() to C code
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From:   Vegard Nossum <vegard.nossum@oracle.com>
To:     Lai Jiangshan <jiangshanlai@gmail.com>,
        linux-kernel@vger.kernel.org
Cc:     Borislav Petkov <bp@alien8.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Andy Lutomirski <luto@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>, x86@kernel.org,
        Lai Jiangshan <jiangshan.ljs@antgroup.com>
References: <20220606144509.617611-1-jiangshanlai@gmail.com>
 <eccf100c-ee04-d42b-c3a6-b747cdad6b7c@oracle.com>
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On 6/9/22 11:11, Vegard Nossum wrote:
> On 6/6/22 16:45, Lai Jiangshan wrote:
>> From: Lai Jiangshan <jiangshan.ljs@antgroup.com>
>>
>> Add some C equivalent functions of the ASM macros and implement the whole
>> error_entry() as C code.
> 
> Hi,
> 
> I did some testing of your patches (on top of mainline commit
> 34f4335c16a5) and I see these two KASAN reports very occasionally during
> boot:
> 
> 1)
> 
> Mountpoint-cache hash table entries: 2048 (order: 2, 16384 bytes, linear)
> ==================================================================
> BUG: KASAN: wild-memory-access in rcu_nmi_enter+0x6e/0xf0

So this one I get without your patches as well. It's only about 1% of
boots, though. Let me try to bisect this and start a new thread.

> 2)
>
> BUG: KASAN: out-of-bounds in rcu_nmi_enter+0x6e/0xf0
> Read of size 4 at addr ff11000034e38b10 by task swapper/0/0

I haven't seen this without your patches, although it's the exact same
callsite so I assume it must be related to the first problem.


Vegard