Re: [Bugme-new] [Bug 11792] New: Oops when reading /proc/megaraid/hba0/diskdrives-ch*

[Boaz Harrosh <bharrosh@panasas.com>]

Yang, Bo wrote:
> Thanks TOMM.  If this is the case, it may affect some of other drivers like our 
> MPT and SAS driver.  Is there a way kernel can fix it?
> 
> Thanks,
> 
> Bo Yang
> 

Hi Bo Yang

What are the source files for the MPT and SAS drivers from LSI?
I have made a system wide search for such problems as below and could not
find any more. But I might have missed them. If you tell me the file names
I will inspect more closly.

Thanks
Boaz

> -----Original Message-----
> From: FUJITA Tomonori [mailto:fujita.tomonori@lab.ntt.co.jp]
> Sent: Wednesday, October 22, 2008 9:39 AM
> To: Yang, Bo
> Cc: fujita.tomonori@lab.ntt.co.jp; bharrosh@panasas.com; pterjan@gmail.com; matthew@wil.cx; akpm@linux-foundation.org; linux-scsi@vger.kernel.org; Patro, Sumant; bugme-daemon@bugzilla.kernel.org; Austria, Winston
> Subject: RE: [Bugme-new] [Bug 11792] New: Oops when reading /proc/megaraid/hba0/diskdrives-ch*
> 
> On Wed, 22 Oct 2008 07:03:03 -0600
> "Yang, Bo" <Bo.Yang@lsi.com> wrote:
> 
>> I saw the latest working kernel: 2.6.24 and first failing kernel
>> version: 2.6.27-rc8.  I understand there are lots of changes between
>> those two kernels.  Can you take a look the changes from kernels to
>> find out the root cause?
> 
> Sorry, I didn't explain the possible root cause.
> 
> struct scsi_cmnd in 2.6.25:
> 
> unsigned char cmnd[MAX_COMMAND_SIZE];
> 
> 
> struct scsi_cmnd in 2.6.26:
> 
> unsigned char *cmnd;
> 
> 
> In short, struct scsi_cmnd doesn't have static array for cdb. You need
> to allocate memory for it (the scsi midlayer does for common usage).
> 
> So
> 
> static int
> mega_internal_command(adapter_t *adapter, megacmd_t *mc, mega_passthru *pthru)
> {
> ...
>         scb = &adapter->int_scb;
>         memset(scb, 0, sizeof(scb_t));
> 
>         scmd = &adapter->int_scmd;
>         memset(scmd, 0, sizeof(Scsi_Cmnd));
> 
>         sdev = kzalloc(sizeof(struct scsi_device), GFP_KERNEL);
>         scmd->device = sdev;
> 
>         scmd->device->host = adapter->host;
>         scmd->host_scribble = (void *)scb;
>         scmd->cmnd[0] = MEGA_INTERNAL_CMD;
> 
> I suspect that the driver crashes here. My patch adds array to
> adapter_t and use it here.
> 
> After 2.6.25, sense_buffer also is converted from static array to
> pointer. In general, using scsi_allocate_command/scsi_free_command is
> the recommended way to use struct scsi_cmnd.
> 
> So my latest patch removes struct scsi_cmnd in adapter_t and uses the
> API in mega_internal_command().
> 
> 
>> Also if you believe this is the driver issue and need LSI to help,
>> can you report this issue to LSI?
> 
> Yeah, I think that we need to update this driver because of the
> changes to SCSI mid-layer.
> 
> It would be appreciated if you can test my latest path:
> 
> http://marc.info/?l=linux-scsi&m=122467887502481&w=2
> 
> 
> Can you think of this thread as a bug report to LSI?
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