From: Ben Hutchings <ben@decadent.org.uk>
Date: Sun, 12 Feb 2012 06:00:41 +0000 (+0000)
Subject: cdc-wdm: Fix more races on the read path
X-Git-Tag: v3.4-rc1~184^2~22^2~108
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=711c68b3c0f7a924ffbee4aa962d8f62b85188ff;p=pandora-kernel.git

cdc-wdm: Fix more races on the read path

We must not allow the input buffer length to change while we're
shuffling the buffer contents.  We also mustn't clear the WDM_READ
flag after more data might have arrived.  Therefore move both of these
into the spinlocked region at the bottom of wdm_read().

When reading desc->length without holding the iuspin lock, use
ACCESS_ONCE() to ensure the compiler doesn't re-read it with
inconsistent results.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Tested-by: Bjørn Mork <bjorn@mork.no>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

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