Staging: rt2860sta: prevent a panic when disabling when associated

This fixes a panic which is triggered when the hardware "disappears" from
beneath the driver, i.e. when wireless is toggled off via Fn-F2 on various
EeePC models.

Ref. bug report http://bugzilla.kernel.org/show_bug.cgi?id=13390
          panic http://bugzilla.kernel.org/attachment.cgi?id=21928

Signed-off-by: Darren Salt <linux@youmustbejoking.demon.co.uk>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/staging/rt2860/common/cmm_data_2860.c b/drivers/staging/rt2860/common/cmm_data_2860.c
index fb1735533b74..857ff450b6c9 100644
--- a/drivers/staging/rt2860/common/cmm_data_2860.c
+++ b/drivers/staging/rt2860/common/cmm_data_2860.c
@@ -363,6 +363,8 @@ int RtmpPCIMgmtKickOut(
         ULONG                   SwIdx = pAd->MgmtRing.TxCpuIdx;
 
         pTxD  = (PTXD_STRUC) pAd->MgmtRing.Cell[SwIdx].AllocVa;
+        if (!pTxD)
+                return 0;
 
         pAd->MgmtRing.Cell[SwIdx].pNdisPacket = pPacket;
         pAd->MgmtRing.Cell[SwIdx].pNextNdisPacket = NULL;