On Sat, Sep 07, 2024 at 03:12:13PM +0100, Catalin Marinas wrote:
> On Fri, Sep 06, 2024 at 04:38:56PM +0100, Vincent Donnefort wrote:
> > commit ac3b43283923 ("module: replace module_layout with module_memory")
> > introduced a set of memory regions for the module layout sharing the
> > same attributes but didn't update the kmemleak scanned areas which
> > intended to limit kmemleak scan to sections containing writable data.
> > This means sections such as .text and .rodata are scanned by kmemleak.
> >
> > Refine the scanned areas for modules by limiting it to MOD_TEXT and
> > MOD_INIT_TEXT mod_mem regions.
> >
> > CC: Song Liu <song@xxxxxxxxxx>
> > CC: Catalin Marinas <catalin.marinas@xxxxxxx>
> > Signed-off-by: Vincent Donnefort <vdonnefort@xxxxxxxxxx>
> >
> > diff --git a/kernel/module/debug_kmemleak.c b/kernel/module/debug_kmemleak.c
> > index 12a569d361e8..b4cc03842d70 100644
> > --- a/kernel/module/debug_kmemleak.c
> > +++ b/kernel/module/debug_kmemleak.c
> > @@ -12,19 +12,9 @@
> > void kmemleak_load_module(const struct module *mod,
> > const struct load_info *info)
> > {
> > - unsigned int i;
> > -
> > - /* only scan the sections containing data */
> > - kmemleak_scan_area(mod, sizeof(struct module), GFP_KERNEL);
> > -
> > - for (i = 1; i < info->hdr->e_shnum; i++) {
> > - /* Scan all writable sections that's not executable */
> > - if (!(info->sechdrs[i].sh_flags & SHF_ALLOC) ||
> > - !(info->sechdrs[i].sh_flags & SHF_WRITE) ||
> > - (info->sechdrs[i].sh_flags & SHF_EXECINSTR))
> > - continue;
> > -
> > - kmemleak_scan_area((void *)info->sechdrs[i].sh_addr,
> > - info->sechdrs[i].sh_size, GFP_KERNEL);
> > + /* only scan writable, non-executable sections */
> > + for_each_mod_mem_type(type) {
> > + if (type != MOD_DATA && type != MOD_INIT_DATA)
> > + kmemleak_no_scan(mod->mem[type].base);
> > }
> > }
>
> I lost track of how module memory allocation works. Is struct module
> still scanned after this change?
That section being RW, it will be part of the MOD_DATA vmalloc and scanned.
--
Vincent
>
> --
> Catalin
