[PATCH] scsi: pmcraid: Fix memory allocation in 'pmcraid_alloc_sglist()'

From: Christophe JAILLET
Date: Sun Sep 20 2020 - 03:57:39 EST

When the scatter list is allocated in 'pmcraid_alloc_sglist()', the
corresponding pointer should be stored in 'scatterlist' within the
'pmcraid_sglist' structure. Otherwise, 'scatterlist' is NULL.

This leads to a potential memory leak and NULL pointer dereference.

Fixes: ed4414cef2ad ("scsi: pmcraid: Use sgl_alloc_order() and sgl_free_order()")
Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
This patch is completely speculative and untested.

Should it be correct, I think that their should be some trouble somewhere.
Either NULL pointer dereference or incorrect behavior.
The patch that introduced this potential bug is 2 years 1/2 old. This
should have been spotted earlier.

So unless this driver is mostly unused, this looks odd to me.
Feedback appreciated.
drivers/scsi/pmcraid.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/pmcraid.c b/drivers/scsi/pmcraid.c
index d99568fdf4af..00e155c88f03 100644
--- a/drivers/scsi/pmcraid.c
+++ b/drivers/scsi/pmcraid.c
@@ -3230,8 +3230,9 @@ static struct pmcraid_sglist *pmcraid_alloc_sglist(int buflen)
return NULL;

sglist->order = order;
- sgl_alloc_order(buflen, order, false,
- GFP_KERNEL | GFP_DMA | __GFP_ZERO, &sglist->num_sg);
+ sglist->scatterlist = sgl_alloc_order(buflen, order, false,
+ &sglist->num_sg);

return sglist;