* Andrey Konovalov <andreyknvl@xxxxxxxxxx> wrote: > The krealloc function checks where the same buffer was reused or a new one > allocated by comparing kernel pointers. KHWASAN changes memory tag on the > krealloc'ed chunk of memory and therefore also changes the pointer tag of > the returned pointer. Therefore we need to perform comparison on untagged > (with tags reset) pointers to check whether it's the same memory region or > not. > > Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> > --- > mm/slab_common.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/slab_common.c b/mm/slab_common.c > index a33e61315ca6..5911f2194cf7 100644 > --- a/mm/slab_common.c > +++ b/mm/slab_common.c > @@ -1494,7 +1494,7 @@ void *krealloc(const void *p, size_t new_size, gfp_t flags) > } > > ret = __do_krealloc(p, new_size, flags); > - if (ret && p != ret) > + if (ret && khwasan_reset_tag(p) != khwasan_reset_tag(ret)) > kfree(p); Small nit: If 'reset' here means an all zeroes tag (upper byte) then khwasan_clear_tag() might be a slightly easier to read primitive? Thanks, Ingo
