Messages in this thread | | | Date | Fri, 08 Mar 2013 18:25:00 -0500 | From | Douglas Gilbert <> | Subject | Re: [patch] [SCSI] scsi_transport_sas: check for allocation failure |
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On 13-03-08 05:50 PM, James Bottomley wrote: > On Fri, 2013-03-08 at 12:57 -0500, Douglas Gilbert wrote: >> On 13-03-08 07:02 AM, Dan Carpenter wrote: >>> Static checkers complain that this allocation isn't checked. We >>> should return zero if the allocation fails. >>> >>> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> >>> >>> diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c >>> index 1b68142..a022997 100644 >>> --- a/drivers/scsi/scsi_transport_sas.c >>> +++ b/drivers/scsi/scsi_transport_sas.c >>> @@ -379,9 +379,12 @@ sas_tlr_supported(struct scsi_device *sdev) >>> { >>> const int vpd_len = 32; >>> struct sas_end_device *rdev = sas_sdev_to_rdev(sdev); >>> - char *buffer = kzalloc(vpd_len, GFP_KERNEL); >>> + char *buffer; >>> int ret = 0; >>> >>> + buffer = kzalloc(vpd_len, GFP_KERNEL); >>> + if (!buffer) >>> + goto out; >>> if (scsi_get_vpd_page(sdev, 0x90, buffer, vpd_len)) >>> goto out; >>> >> >> For 32 bytes, why not use the stack? > > Because the buffer is a DMA target. You can't DMA to stack because of > padding and cacheline issues.
And I went to the definition of scsi_get_vpd_page() to see if that was called out in the header comments. Guess what ... and those same header comments talked about freeing a returned pointer. It needs to be cleaned up, IMO.
Doug Gilbert
/** * scsi_get_vpd_page - Get Vital Product Data from a SCSI device * @sdev: The device to ask * @page: Which Vital Product Data to return * @buf: where to store the VPD * @buf_len: number of bytes in the VPD buffer area * * SCSI devices may optionally supply Vital Product Data. Each 'page' * of VPD is defined in the appropriate SCSI document (eg SPC, SBC). * If the device supports this VPD page, this routine returns a pointer * to a buffer containing the data from that page. The caller is * responsible for calling kfree() on this pointer when it is no longer * needed. If we cannot retrieve the VPD page this routine returns %NULL. */ int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf, int buf_len)
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