On Fri, Jun 27, 2025 at 12:51:02PM +0100, Andrew Goodbody wrote: > The local variable ranges may be used uninitialised if the function > fdt_get_dma_range is called with node < 0. Ensure this does not > happen by initialising ranges when declared.
It doesn't harm. When node < 0, parent is less than zero as well, and the first while loop is skipped. The control flow just fails into the error path where parent < 0 stays true. Furthermore, it doesn't seem valid to call fdt_get_dma_range() with a negative node parameter, does it? > /** > * fdt_get_dma_range() - get DMA ranges to perform bus/cpu translations > * > * @blob: pointer to device tree blob > * @node_offset: node DT offset > * @cpu: pointer to variable storing the range's cpu address > * @bus: pointer to variable storing the range's bus address > * @size: pointer to variable storing the range's size > * > * Get DMA ranges for a specifc node, this is useful to perform bus->cpu and > * cpu->bus address translations > * > * Return: translated DMA address or OF_BAD_ADDR on error > */ > int fdt_get_dma_range(const void *blob, int node_offset, phys_addr_t *cpu, > dma_addr_t *bus, u64 *size); Regards, Yao Zi > This issue was found with Smatch. > > Signed-off-by: Andrew Goodbody <[email protected]> > --- > boot/fdt_support.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/boot/fdt_support.c b/boot/fdt_support.c > index 92f2f534ee0..4f63ce9a763 100644 > --- a/boot/fdt_support.c > +++ b/boot/fdt_support.c > @@ -1547,7 +1547,7 @@ int fdt_get_dma_range(const void *blob, int node, > phys_addr_t *cpu, > { > bool found_dma_ranges = false; > struct of_bus *bus_node; > - const fdt32_t *ranges; > + const fdt32_t *ranges = NULL; > int na, ns, pna, pns; > int parent = node; > int ret = 0; > > --- > base-commit: 359e3012921f2fc2d43f3c4e320a752173f82b82 > change-id: 20250627-boot_fdt_fix-e4e56d956c8a > > Best regards, > -- > Andrew Goodbody <[email protected]> >
