Re: [PATCH] ARM: Fix incorrect FDT initrd parameter override

Ben,

On Tue, Jan 14, 2014 at 07:08:30AM +1000, Ben Peddell wrote:

Patch submitted with requested changes.

On Mon, 13 Jan 2014 at 10:28:51 AM -0500, Jason Cooper wrote:

quoted

quoted

+	initrd_start = initrd_end = 0;

This line shouldn't be necessary.  Both are reset in the following hunk
below your change:

if (phys_initrd_size &&
    !memblock_is_region_memory(phys_initrd_start, phys_initrd_size)) {
	pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region - disabling initrd\n",
	       (u64)phys_initrd_start, phys_initrd_size);
	phys_initrd_start = phys_initrd_size = 0;
}
if (phys_initrd_size &&
    memblock_is_region_reserved(phys_initrd_start, phys_initrd_size)) {
	pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region - disabling initrd\n",
	       (u64)phys_initrd_start, phys_initrd_size);
	phys_initrd_start = phys_initrd_size = 0;
}

quoted

if (phys_initrd_size) {
	memblock_reserve(phys_initrd_start, phys_initrd_size);

	/* Now convert initrd to virtual addresses */
	initrd_start = __phys_to_virt(phys_initrd_start);
	initrd_end = initrd_start + phys_initrd_size;
}

Please note that above this a check is made to ensure that
phys_initrd_start and phys_initrd_size are valid, and they are zeroed
if they are not valid.  Therefore if phys_initrd_start or 
phys_initrd_size are invalid, then initrd_start and initrd_end are not
reset.

This means that if the initrd= address is not present or is invalid
then the FDT address will be used anyway as initrd_start and 
initrd_end will not have been zeroed, and if that is invalid the
kernel will OOPS in unpack_to_rootfs():

Ahhh, ok.  Thanks for the clarification.  You kept that line in the
version you submitted to Russell's patch tracker?

thx,

Jason.
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