Re: [PATCH 8/8] scsi: ufs: Check for completion from the timeout handler

[Bart Van Assche <bvanassche@xxxxxxx>]

On 6/25/24 8:54 PM, Peter Wang (王信友) wrote:
> And why ufshcd_queuecommand got null pointer? which pointer is null?

I'm not sure. faddr2line reports that the crash happens in the source
code line with the following assignment: "sg_dma_len(sg) = sg->length".
That seems weird to me. If the sg pointer would be invalid then an
earlier dereference of the 'sg' pointer should already have triggered a
crash. The entire function is as follows:

int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int 
nents,
		enum dma_data_direction dir, unsigned long attrs)
{
	int i;
	struct scatterlist *sg;

	for_each_sg(sgl, sg, nents, i) {
		sg->dma_address = dma_direct_map_page(dev, sg_page(sg),
				sg->offset, sg->length, dir, attrs);
		if (sg->dma_address == DMA_MAPPING_ERROR)
			goto out_unmap;
		sg_dma_len(sg) = sg->length;
	}

	return nents;

out_unmap:
	dma_direct_unmap_sg(dev, sgl, i, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC);
	return -EIO;
}

Bart.