Re: [PATCH 2/2] bnx2fc: fix memory leak and potential NULL pointer dereference.

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Hi Eddie,

On Fri, Mar 07, 2014 at 11:21:45AM -0800, Eddie Wai wrote:
> Hello Maurizio,
> 
> Thanks for looking into this.  The patch looks good, but I would like to
> extend it with the following allocation failure portion to completely
> remove the memory leak.  Please incorporate this into your next
> submission.

Thanks for the patch you sent,

maybe it is even better if I modify bnx2fc_allocate_hash_table() in such a way
that, in case of error, it frees all the memory it has allocated.

Note that your patch does not free the table if
"hba->hash_tbl_pbl = dma_alloc_coherent(...)" fails (line 2058).

It just requires a very little change to your patch, I'll send it tomorrow.

Regards,
Maurizio Lombardi

> 
> Thanks,
> Eddie
> 
> @@ -2020,7 +2026,7 @@ static int bnx2fc_allocate_hash_table(struct
> bnx2fc_hba *hba)
>         dma_segment_array = kzalloc(dma_segment_array_size, GFP_KERNEL);
>         if (!dma_segment_array) {
>                 printk(KERN_ERR PFX "hash table pointers (dma) alloc
> failed\n");
> -               return -ENOMEM;
> +               goto free_hash_tbl_seg;
>         }
> 
>         for (i = 0; i < segment_count; ++i) {
> @@ -2039,7 +2045,7 @@ static int bnx2fc_allocate_hash_table(struct
> bnx2fc_hba *hba)
>                                 hba->hash_tbl_segments[i] = NULL;
>                         }
>                         kfree(dma_segment_array);
> -                       return -ENOMEM;
> +                       goto free_hash_tbl_seg;
>                 }
>                 memset(hba->hash_tbl_segments[i], 0,
>                        BNX2FC_HASH_TBL_CHUNK_SIZE);
> @@ -2077,6 +2083,11 @@ static int bnx2fc_allocate_hash_table(struct
> bnx2fc_hba *hba)
>         }
>         kfree(dma_segment_array);
>         return 0;
> +
> +free_hash_tbl_seg:
> +       kfree(hba->hash_tbl_segments);
> +       hba->hash_tbl_segments = NULL;
> +       return -ENOMEM;
>  }
> 
> 
> On Fri, 2014-03-07 at 15:37 +0100, Maurizio Lombardi wrote:
> > If bnx2fc_allocate_hash_table() for some reasons fails, it is possible that the
> > hash_tbl_segments or the hash_tbl_pbl pointers are NULL.
> > In this case bnx2fc_free_hash_table() will panic the system.
> > 
> > this patch also fixes a memory leak, the hash_tbl_segments pointer was never
> > freed.
> > 
> > Signed-off-by: Maurizio Lombardi <mlombard@xxxxxxxxxx>
> > ---
> >  drivers/scsi/bnx2fc/bnx2fc_hwi.c | 34 ++++++++++++++++++++--------------
> >  1 file changed, 20 insertions(+), 14 deletions(-)
> > 
> > diff --git a/drivers/scsi/bnx2fc/bnx2fc_hwi.c b/drivers/scsi/bnx2fc/bnx2fc_hwi.c
> > index 261af2a..f83bae4 100644
> > --- a/drivers/scsi/bnx2fc/bnx2fc_hwi.c
> > +++ b/drivers/scsi/bnx2fc/bnx2fc_hwi.c
> > @@ -1968,21 +1968,27 @@ static void bnx2fc_free_hash_table(struct bnx2fc_hba *hba)
> >  	int segment_count;
> >  	u32 *pbl;
> >  
> > -	segment_count = hba->hash_tbl_segment_count;
> > -
> > -	pbl = hba->hash_tbl_pbl;
> > -	for (i = 0; i < segment_count; ++i) {
> > -		dma_addr_t dma_address;
> > -
> > -		dma_address = le32_to_cpu(*pbl);
> > -		++pbl;
> > -		dma_address += ((u64)le32_to_cpu(*pbl)) << 32;
> > -		++pbl;
> > -		dma_free_coherent(&hba->pcidev->dev,
> > -				  BNX2FC_HASH_TBL_CHUNK_SIZE,
> > -				  hba->hash_tbl_segments[i],
> > -				  dma_address);
> > +	if (hba->hash_tbl_segments) {
> > +
> > +		pbl = hba->hash_tbl_pbl;
> > +		if (pbl) {
> > +			segment_count = hba->hash_tbl_segment_count;
> > +			for (i = 0; i < segment_count; ++i) {
> > +				dma_addr_t dma_address;
> > +
> > +				dma_address = le32_to_cpu(*pbl);
> > +				++pbl;
> > +				dma_address += ((u64)le32_to_cpu(*pbl)) << 32;
> > +				++pbl;
> > +				dma_free_coherent(&hba->pcidev->dev,
> > +						  BNX2FC_HASH_TBL_CHUNK_SIZE,
> > +						  hba->hash_tbl_segments[i],
> > +						  dma_address);
> > +			}
> > +		}
> >  
> > +		kfree(hba->hash_tbl_segments);
> > +		hba->hash_tbl_segments = NULL;
> >  	}
> >  
> >  	if (hba->hash_tbl_pbl) {
> 
> 
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