From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Chandan Rajendra <chandan@linux.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Cc: Anton Blanchard <anton@au1.ibm.com>,
Nick Piggin <npiggin@au1.ibm.com>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Subject: Re: BUG: memcmp(): Accessing invalid memory location
Date: Fri, 25 Jan 2019 07:45:14 +0100 [thread overview]
Message-ID: <c6395c70-cac3-649e-c96b-4b109069265b@c-s.fr> (raw)
In-Reply-To: <3517bf7d54e9a2c6cdd054cefd75b5e073823042.camel@kernel.crashing.org>
Le 25/01/2019 à 01:55, Benjamin Herrenschmidt a écrit :
> On Thu, 2019-01-24 at 19:48 +0530, Chandan Rajendra wrote:
>> - Here we execute "LD rB,0,r4". In the case of this bug, r4 has an unaligned
>> value and hence ends up accessing the "next" double word. The "next" double
>> word happens to occur after the last page mapped into the kernel's address
>> space and hence this leads to the previously listed oops.
>>
>
> This is interesting ... should we mark the last page of any piece of
> mapped linear mapping as reserved to avoid that sort of issue ?
Or revert to a normal comparison once remaining length is < 8 and r4 in
unaligned ?
Christophe
>
> Nick ? Aneesh ?
>
> Cheers,
> Ben.
>
next prev parent reply other threads:[~2019-01-25 6:47 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-24 14:18 BUG: memcmp(): Accessing invalid memory location Chandan Rajendra
2019-01-25 0:55 ` Benjamin Herrenschmidt
2019-01-25 6:45 ` Christophe Leroy [this message]
2019-01-31 10:30 ` Michael Ellerman
2019-02-01 11:13 ` Michael Ellerman
2019-02-04 3:14 ` Chandan Rajendra
2019-02-06 11:50 ` Michael Ellerman
2019-02-06 12:42 ` Chandan Rajendra
2019-02-06 23:57 ` Michael Ellerman
2019-02-07 2:13 ` Chandan Rajendra
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