On Thu, 2019-06-20 at 14:26 +0800, Ming Lei wrote:
> The local variable 'sg' should be initialized in the failure path of
> mvumi_make_sgl(), otherwise the following build warning is triggered:
>
> In file included from include/linux/pci-dma-compat.h:8,
> from include/linux/pci.h:2408,
> from drivers/scsi/mvumi.c:13:
> drivers/scsi/mvumi.c: In function 'mvumi_queue_command':
> include/linux/dma-mapping.h:608:34: warning: 'sg' may be used
> uninitialized in this function
> +[-Wmaybe-uninitialized]
> #define dma_unmap_sg(d, s, n, r) dma_unmap_sg_attrs(d, s, n,
> r, 0)
> ^~~~~~~~~~~~~~~~~~
> drivers/scsi/mvumi.c:192:22: note: 'sg' was declared here
> struct scatterlist *sg;
> ^~
> Fixed it by removing the local variable reference in failure path.
>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Bart Van Assche <bvanassche@xxxxxxx>
> Cc: Ewan D. Milne <emilne@xxxxxxxxxx>
> Fixes: 350d66a72adc ("scsi: mvumi: use sg helper to iterate over
> scatterlist")
> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
> ---
> drivers/scsi/mvumi.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/mvumi.c b/drivers/scsi/mvumi.c
> index 0022cd31500a..53f3563aca22 100644
> --- a/drivers/scsi/mvumi.c
> +++ b/drivers/scsi/mvumi.c
> @@ -217,7 +217,7 @@ static int mvumi_make_sgl(struct mvumi_hba *mhba,
> struct scsi_cmnd *scmd,
> dev_err(&mhba->pdev->dev,
> "sg count[0x%x] is bigger than max
> sg[0x%x].\n",
> *sg_count, mhba->max_sge);
> - dma_unmap_sg(&mhba->pdev->dev, sg, sgnum,
> + dma_unmap_sg(&mhba->pdev->dev, scsi_sglist(scmd),
> sgnum,
> scmd->sc_data_direction);
> return -1;
> }
I think this is a serious enough problem for mvumi that it needs
folding with comment into the original path. I believe it will cause
an oops when this code path is hit otherwise, right?
James
