Re: [PATCH 3/3] slub: Actually use 'message' in restore_bytes()

From: Stephen Boyd
Date: Tue May 25 2021 - 22:33:10 EST


Quoting Joe Perches (2021-05-25 00:37:45)
> On Sun, 2021-05-23 at 22:12 -0700, David Rientjes wrote:
> > On Wed, 19 May 2021, Stephen Boyd wrote:
> >
> > > The message argument isn't used here. Let's pass the string to the
> > > printk message so that the developer can figure out what's happening,
> > > instead of guessing that a redzone is being restored, etc.
> > >
> > > Signed-off-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
> >
> > Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
>
> Ideally, the slab_fix function would be marked with __printf and the
> format here would not use \n as that's emitted by the slab_fix.

Thanks. I can make this into a proper patch and author it from you. Can
you provide a signed-off-by? The restore_bytes() hunk is slightly
different but I can fix that up.

> ---
> mm/slub.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/mm/slub.c b/mm/slub.c
> index ee51857d8e9bc..46f9b043089b6 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -702,6 +702,7 @@ static void slab_bug(struct kmem_cache *s, char *fmt, ...)
> va_end(args);
> }
>
> +__printf(2, 3)
> static void slab_fix(struct kmem_cache *s, char *fmt, ...)
> {
> struct va_format vaf;
> @@ -816,7 +817,8 @@ static void init_object(struct kmem_cache *s, void *object, u8 val)
> static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
> void *from, void *to)
> {
> - slab_fix(s, "Restoring %s 0x%px-0x%px=0x%x\n", message, from, to - 1, data);
> + slab_fix(s, "Restoring %s 0x%px-0x%px=0x%x",
> + message, from, to - 1, data);
> memset(from, data, to - from);
> }
>
> @@ -1069,13 +1071,13 @@ static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
> slab_err(s, page, "Wrong number of objects. Found %d but should be %d",
> page->objects, max_objects);
> page->objects = max_objects;
> - slab_fix(s, "Number of objects adjusted.");
> + slab_fix(s, "Number of objects adjusted");
> }
> if (page->inuse != page->objects - nr) {
> slab_err(s, page, "Wrong object count. Counter is %d but counted were %d",
> page->inuse, page->objects - nr);
> page->inuse = page->objects - nr;
> - slab_fix(s, "Object count adjusted.");
> + slab_fix(s, "Object count adjusted");
> }
> return search == NULL;
> }
>
>