Re: [PATCH v3 sl-b 1/6] mm: Add mem_dump_obj() to print source of memory block

[Paul E. McKenney]

On Thu, Dec 10, 2020 at 07:33:59PM -0800, Paul E. McKenney wrote:
> On Fri, Dec 11, 2020 at 11:22:10AM +0900, Joonsoo Kim wrote:
> > On Thu, Dec 10, 2020 at 05:19:58PM -0800, paul...@kernel.org wrote:
> > > From: "Paul E. McKenney" <paul...@kernel.org>

[ . . . ]

> > We can get some infos even if CONFIG_SLUB_DEBUG isn't defined.
> > Please move them out.
> 
> I guess since I worry about CONFIG_MMU=n it only makes sense to also
> worry about CONFIG_SLUB_DEBUG=n.  Fix update.

Like this?  (Patch on top of the series, to be folded into the first one.)

                                                        Thanx, Paul

------------------------------------------------------------------------

diff --git a/mm/slub.c b/mm/slub.c
index 0459d2a..abf43f0 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3920,21 +3920,24 @@ int __kmem_cache_shutdown(struct kmem_cache *s)
 
 void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page)
 {
-#ifdef CONFIG_SLUB_DEBUG
        void *base;
-       int i;
+       int __maybe_unused i;
        unsigned int objnr;
        void *objp;
        void *objp0;
        struct kmem_cache *s = page->slab_cache;
-       struct track *trackp;
+       struct track __maybe_unused *trackp;
 
        kpp->kp_ptr = object;
        kpp->kp_page = page;
        kpp->kp_slab_cache = s;
        base = page_address(page);
        objp0 = kasan_reset_tag(object);
+#ifdef CONFIG_SLUB_DEBUG
        objp = restore_red_left(s, objp0);
+#else
+       objp = objp0;
+#endif
        objnr = obj_to_index(s, page, objp);
        kpp->kp_data_offset = (unsigned long)((char *)objp0 - (char *)objp);
        objp = base + s->size * objnr;
@@ -3942,6 +3945,7 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void 
*object, struct page *page)
        if (WARN_ON_ONCE(objp < base || objp >= base + page->objects * s->size 
|| (objp - base) % s->size) ||
            !(s->flags & SLAB_STORE_USER))
                return;
+#ifdef CONFIG_SLUB_DEBUG
        trackp = get_track(s, objp, TRACK_ALLOC);
        kpp->kp_ret = (void *)trackp->addr;
 #ifdef CONFIG_STACKTRACE