linux-kernel - Re: [PATCH 3/3] slub: Actually use 'message' in restore

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Message-ID: <858b8d14673a200c3c2162fb7a9bf891ecd2a2d9.camel@perches.com>
Date:   Tue, 25 May 2021 00:37:45 -0700
From:   Joe Perches <joe@...ches.com>
To:     David Rientjes <rientjes@...gle.com>,
        Stephen Boyd <swboyd@...omium.org>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        linux-kernel@...r.kernel.org, Christoph Lameter <cl@...ux.com>,
        Pekka Enberg <penberg@...nel.org>,
        Joonsoo Kim <iamjoonsoo.kim@....com>,
        Vlastimil Babka <vbabka@...e.cz>, linux-mm@...ck.org
Subject: Re: [PATCH 3/3] slub: Actually use 'message' in restore_bytes()

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@...omium.org>
> 
> Acked-by: David Rientjes <rientjes@...gle.com>

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.
---
 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;
 }