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staging:rts_pstor:Fix possible panic by NULL pointer dereference

Browse source 
rtsx_transport.c (rtsx_transfer_sglist_adma_partial):
pointer struct scatterlist *sg, which is mapped in dma_map_sg,
is used as an iterator in later transfer operation. It is corrupted and
passed to dma_unmap_sg, thus causing fatal unmap of some erroneous address.
Fix it by duplicating *sg_ptr for iterating.

Signed-off-by: wwang <wei_wang@realsil.com.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
wwang 2012-03-27 16:43:11 +08:00 committed by Greg Kroah-Hartman
parent 4ca5218e39
commit 0d05568ac7
1 changed files with 6 additions and 5 deletions
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11
drivers/staging/rts_pstor/rtsx_transport.c
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@ -335,6 +335,7 @@ static int rtsx_transfer_sglist_adma_partial(struct rtsx_chip *chip, u8 card,
int sg_cnt, i, resid;
int err = 0;
long timeleft;
struct scatterlist *sg_ptr;
u32 val = TRIG_DMA;
if ((sg == NULL) || (num_sg <= 0) || !offset || !index)
@ -371,7 +372,7 @@ static int rtsx_transfer_sglist_adma_partial(struct rtsx_chip *chip, u8 card,
sg_cnt = dma_map_sg(&(rtsx->pci->dev), sg, num_sg, dma_dir);
resid = size;
sg_ptr = sg;
chip->sgi = 0;
/* Usually the next entry will be @sg@ + 1, but if this sg element
* is part of a chained scatterlist, it could jump to the start of
@ -379,14 +380,14 @@ static int rtsx_transfer_sglist_adma_partial(struct rtsx_chip *chip, u8 card,
* the proper sg
*/
for (i = 0; i < *index; i++)
sg = sg_next(sg);
sg_ptr = sg_next(sg_ptr);
for (i = *index; i < sg_cnt; i++) {
dma_addr_t addr;
unsigned int len;
u8 option;
addr = sg_dma_address(sg);
len = sg_dma_len(sg);
addr = sg_dma_address(sg_ptr);
len = sg_dma_len(sg_ptr);
RTSX_DEBUGP("DMA addr: 0x%x, Len: 0x%x\n",
(unsigned int)addr, len);
@ -415,7 +416,7 @@ static int rtsx_transfer_sglist_adma_partial(struct rtsx_chip *chip, u8 card,
if (!resid)
break;
sg = sg_next(sg);
sg_ptr = sg_next(sg_ptr);
}
RTSX_DEBUGP("SG table count = %d\n", chip->sgi);