staging:rts_pstor:Fix possible panic by NULL pointer dereference
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>
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@ -335,6 +335,7 @@ static int rtsx_transfer_sglist_adma_partial(struct rtsx_chip *chip, u8 card,
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int sg_cnt, i, resid;
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int err = 0;
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long timeleft;
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struct scatterlist *sg_ptr;
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u32 val = TRIG_DMA;
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if ((sg == NULL) || (num_sg <= 0) || !offset || !index)
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@ -371,7 +372,7 @@ static int rtsx_transfer_sglist_adma_partial(struct rtsx_chip *chip, u8 card,
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sg_cnt = dma_map_sg(&(rtsx->pci->dev), sg, num_sg, dma_dir);
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resid = size;
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sg_ptr = sg;
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chip->sgi = 0;
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/* Usually the next entry will be @sg@ + 1, but if this sg element
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* is part of a chained scatterlist, it could jump to the start of
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@ -379,14 +380,14 @@ static int rtsx_transfer_sglist_adma_partial(struct rtsx_chip *chip, u8 card,
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* the proper sg
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*/
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for (i = 0; i < *index; i++)
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sg = sg_next(sg);
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sg_ptr = sg_next(sg_ptr);
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for (i = *index; i < sg_cnt; i++) {
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dma_addr_t addr;
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unsigned int len;
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u8 option;
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addr = sg_dma_address(sg);
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len = sg_dma_len(sg);
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addr = sg_dma_address(sg_ptr);
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len = sg_dma_len(sg_ptr);
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RTSX_DEBUGP("DMA addr: 0x%x, Len: 0x%x\n",
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(unsigned int)addr, len);
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@ -415,7 +416,7 @@ static int rtsx_transfer_sglist_adma_partial(struct rtsx_chip *chip, u8 card,
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if (!resid)
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break;
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sg = sg_next(sg);
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sg_ptr = sg_next(sg_ptr);
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}
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RTSX_DEBUGP("SG table count = %d\n", chip->sgi);
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