re: [SCSI] mpt2sas: Fixed Big Indian Issues on 32 bit PPC

re: [SCSI] mpt2sas: Fixed Big Indian Issues on 32 bit PPC

[Dan Carpenter]

Hello Kashyap, Desai,

The patch c97951ec46d4: "[SCSI] mpt2sas: Fixed Big Indian Issues on 
32 bit PPC" from Jun 14, 2011, leads to the following static checker
warning:

drivers/scsi/mpt2sas/mpt2sas_base.c:3352 _base_get_port_facts()
	 warn: are we memsetting too much? 6 vs 28

We changed the size of certain data structures.

-       Mpi2IOCFactsReply_t facts;
-       Mpi2PortFactsReply_t *pfacts;
+       struct mpt2sas_facts facts;
+       struct mpt2sas_port_facts *pfacts;

But it's not done consistently.  We still memset it as if it were the
original size.

	memset(facts, 0, sizeof(Mpi2IOCFactsReply_t));

And we still allocate the original size data structure:

  4270          ioc->pfacts = kcalloc(ioc->facts.NumberOfPorts,
  4271              sizeof(Mpi2PortFactsReply_t), GFP_KERNEL);

There are a couple other warnings as well.
drivers/scsi/mpt2sas/mpt2sas_base.c:3394 _base_get_ioc_facts(24)
	warn: are we memsetting too much? 60 vs 64
drivers/scsi/mpt2sas/mpt2sas_base.c:4270 mpt2sas_base_attach(56)
	warn: double check that we're allocating correct size: 6 vs 28

Obviously the concern with a too big memset is that we're corrupting
the next element in the array or we're corrupting past the end of the
array.

regards,
dan carpenter

RE: [SCSI] mpt2sas: Fixed Big Indian Issues on 32 bit PPC

[Moore, Eric]

Dan - I fixed the issue about a couple weeks ago in the in-house drivers.  From _base_get_ioc_facts, we should be memset'ing the "struct mpt2sas_facts" instead of "Mpi2IOCFactsReply_t ", because the its four bytes larger, the ioc->pfacts is getting set to NULL.   Nagalaksmi will pick it up this fix and post upstream in a future patch.

Thankyou,
Eric

________________________________________
From: linux-scsi-owner@vger.kernel.org [linux-scsi-owner@vger.kernel.org] On Behalf Of Dan Carpenter [dan.carpenter@oracle.com]
Sent: Monday, February 20, 2012 7:05 AM
To: Desai, Kashyap
Cc: linux-scsi@vger.kernel.org
Subject: re: [SCSI] mpt2sas: Fixed Big Indian Issues on 32 bit PPC

Hello Kashyap, Desai,

The patch c97951ec46d4: "[SCSI] mpt2sas: Fixed Big Indian Issues on
32 bit PPC" from Jun 14, 2011, leads to the following static checker
warning:

drivers/scsi/mpt2sas/mpt2sas_base.c:3352 _base_get_port_facts()
         warn: are we memsetting too much? 6 vs 28

We changed the size of certain data structures.

-       Mpi2IOCFactsReply_t facts;
-       Mpi2PortFactsReply_t *pfacts;
+       struct mpt2sas_facts facts;
+       struct mpt2sas_port_facts *pfacts;

But it's not done consistently.  We still memset it as if it were the
original size.

        memset(facts, 0, sizeof(Mpi2IOCFactsReply_t));

And we still allocate the original size data structure:

  4270          ioc->pfacts = kcalloc(ioc->facts.NumberOfPorts,
  4271              sizeof(Mpi2PortFactsReply_t), GFP_KERNEL);

There are a couple other warnings as well.
drivers/scsi/mpt2sas/mpt2sas_base.c:3394 _base_get_ioc_facts(24)
        warn: are we memsetting too much? 60 vs 64
drivers/scsi/mpt2sas/mpt2sas_base.c:4270 mpt2sas_base_attach(56)
        warn: double check that we're allocating correct size: 6 vs 28

Obviously the concern with a too big memset is that we're corrupting
the next element in the array or we're corrupting past the end of the
array.

regards,
dan carpenter

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