Hi Slawomir, On 4/4/22 16:02, Frank Rowand wrote: > On 4/4/22 15:38, Rob Herring wrote: >> On Thu, Mar 31, 2022 at 11:56:33AM +0200, Slawomir Stepien wrote: >>> From: Slawomir Stepien <slawomir.stepien@xxxxxxxxx> >>> >>> Before this change, the memory pointed by fields 'overlay_tree' and >>> 'fdt' will be double freed by a call to free_overlay_changeset() from >>> of_overlay_apply(), when the init_overlay_changeset() fails. >>> >>> The first free will happen under 'err_free_tree' label and for the >>> second time under 'err_free_overlay_changeset' label, where we call >>> free_overlay_changeset(). >>> >>> This could happen for example, when you are applying an overlay to a >>> target path that does not exists. >>> >>> By setting the pointers only when we are sure that >>> init_overlay_changeset() will not fail, will prevent this double free. >> >> It looks to me like the free should just be moved from >> init_overlay_changeset() to of_overlay_fdt_apply() where the allocation >> is done. Frank? > > This patch is next on my list to look over. Thanks for finding this problem. While investigating what you reported I found that there are additional related issues. I am in the process of testing a patch to fix all of the issues. -Frank > > -Frank > >> >> Also, I believe there's a bug that of_overlay_apply() should be passed >> new_fdt_align rather than new_fdt. It's only a bug if we expect >> overlay_changeset.fdt to point to a valid fdt rather than the memory >> allocation. >> >> Rob >
