From: Michael Ellerman <mpe@ellerman.id.au>
To: Daniel Axtens <dja@axtens.net>, linuxppc-dev@ozlabs.org
Cc: mikey@neuling.org, Daniel Axtens <dja@axtens.net>, imunsie@au.ibm.com
Subject: Re: cxl: Check if afu is not null in cxl_slbia
Date: Fri, 10 Jul 2015 16:55:06 +1000 (AEST) [thread overview]
Message-ID: <20150710065506.72FE41402D6@ozlabs.org> (raw)
In-Reply-To: <1436483065-9202-1-git-send-email-dja@axtens.net>
On Thu, 2015-09-07 at 23:04:25 UTC, Daniel Axtens wrote:
> The pointer to an AFU in the adapter's list of AFUs can be null
> if we're in the process of removing AFUs. The afu_list_lock
> doesn't guard against this.
>
> Say we have 2 slices, and we're in the process of removing cxl.
> - We remove the AFUs in order (see cxl_remove). In cxl_remove_afu
> for AFU 0, we take the lock, set adapter->afu[0] = NULL, and
> release the lock.
> - Then we get an slbia. In cxl_slbia we take the lock, and set
> afu = adapter->afu[0], which is NULL.
> - Therefore our attempt to check afu->enabled will blow up.
>
> Therefore, check if afu is a null pointer before dereferencing it.
>
Cc: stable@vger.kernel.org
> Signed-off-by: Daniel Axtens <dja@axtens.net>
> Acked-by: Michael Neuling <mikey@neuling.org>
> Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Applied to powerpc fixes, thanks.
https://git.kernel.org/powerpc/c/2c069a118fe1d80c47dc
cheers
prev parent reply other threads:[~2015-07-10 6:55 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-09 23:04 [PATCH] cxl: Check if afu is not null in cxl_slbia Daniel Axtens
2015-07-09 23:50 ` Michael Neuling
2015-07-10 0:09 ` Ian Munsie
2015-07-10 6:55 ` Michael Ellerman [this message]
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