From: <miles.chen@mediatek.com>
To: Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
<linux-mediatek@lists.infradead.org>, <wsd_upstream@mediatek.com>,
Miles Chen <miles.chen@mediatek.com>
Subject: [RFC PATCH] mm: slub: print kernel addresses when CONFIG_SLUB_DEBUG=y
Date: Thu, 8 Aug 2019 22:28:43 +0800 [thread overview]
Message-ID: <20190808142843.32151-1-miles.chen@mediatek.com> (raw)
From: Miles Chen <miles.chen@mediatek.com>
This RFC patch is sent to discuss the printing address with %p issue.
Since commit ad67b74d2469d9b8 ("printk: hash addresses printed with %p"),
%p gives obfuscated addresses now. When CONFIG_SLUB_DEBUG=y, it is still
useful to get real virtual addresses.
Possible approaches are:
1. stop printing kernel addresses
2. print kernel addresses with %pK,
3. print kernel addresses with %px.
4. do nothing
This patch takes %px approach and shows the output here.
(%px will causes checkpatch warnings, let us ignore the warning here to
have the discussion). Also, use DUMP_PREFIX_OFFSET instead of
DUMP_PREFIX_ADDRESS.
Before this patch:
INFO: Slab 0x(____ptrval____) objects=25 used=10 fp=0x(____ptrval____)
INFO: Object 0x(____ptrval____) @offset=1408 fp=0x(____ptrval____)
Redzone (____ptrval____): bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
Redzone (____ptrval____): bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
Redzone (____ptrval____): bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
Redzone (____ptrval____): bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
Redzone (____ptrval____): bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
Redzone (____ptrval____): bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
Redzone (____ptrval____): bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
Redzone (____ptrval____): bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
Object (____ptrval____): 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
Object (____ptrval____): 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
Object (____ptrval____): 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
Object (____ptrval____): 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
Object (____ptrval____): 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
Object (____ptrval____): 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
Object (____ptrval____): 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
Object (____ptrval____): 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5
Redzone (____ptrval____): bb bb bb bb bb bb bb bb
Padding (____ptrval____): 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a
Padding (____ptrval____): 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a
Padding (____ptrval____): 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a
Padding (____ptrval____): 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a
...
FIX kmalloc-128: Object at 0x(____ptrval____) not freed
After this patch:
INFO: Slab 0xffffffbf00f57000 objects=25 used=23 fp=0xffffffc03d5c3500
INFO: Object 0xffffffc03d5c3500 @offset=13568 fp=0xffffffc03d5c0800
Redzone 00000000: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
Redzone 00000010: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
Redzone 00000020: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
Redzone 00000030: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
Redzone 00000040: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
Redzone 00000050: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
Redzone 00000060: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
Redzone 00000070: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
Object 00000000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
Object 00000010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
Object 00000020: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
Object 00000030: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
Object 00000040: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
Object 00000050: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
Object 00000060: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
Object 00000070: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5
Redzone 00000000: bb bb bb bb bb bb bb bb
Padding 00000000: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a
Padding 00000010: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a
Padding 00000020: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a
Padding 00000030: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a
...
FIX kmalloc-128: Object at 0xffffffc03d5c3500 not freed
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
---
mm/slub.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c
index 8834563cdb4b..bc1fb8e81557 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -528,7 +528,7 @@ static void print_section(char *level, char *text, u8 *addr,
unsigned int length)
{
metadata_access_enable();
- print_hex_dump(level, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
+ print_hex_dump(level, text, DUMP_PREFIX_OFFSET, 16, 1, addr,
length, 1);
metadata_access_disable();
}
@@ -611,7 +611,7 @@ static void print_tracking(struct kmem_cache *s, void *object)
static void print_page_info(struct page *page)
{
- pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
+ pr_err("INFO: Slab 0x%px objects=%u used=%u fp=0x%px flags=0x%04lx\n",
page, page->objects, page->inuse, page->freelist, page->flags);
}
@@ -653,7 +653,7 @@ static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
print_page_info(page);
- pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
+ pr_err("INFO: Object 0x%px @offset=%tu fp=0x%px\n\n",
p, p - addr, get_freepointer(s, p));
if (s->flags & SLAB_RED_ZONE)
@@ -991,7 +991,7 @@ static void trace(struct kmem_cache *s, struct page *page, void *object,
int alloc)
{
if (s->flags & SLAB_TRACE) {
- pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
+ pr_info("TRACE %s %s 0x%px inuse=%d fp=0x%p\n",
s->name,
alloc ? "alloc" : "free",
object, page->inuse,
@@ -1212,7 +1212,7 @@ static noinline int free_debug_processing(
slab_unlock(page);
spin_unlock_irqrestore(&n->list_lock, flags);
if (!ret)
- slab_fix(s, "Object at 0x%p not freed", object);
+ slab_fix(s, "Object at 0x%px not freed", object);
return ret;
}
@@ -3693,7 +3693,7 @@ static void list_slab_objects(struct kmem_cache *s, struct page *page,
for_each_object(p, s, addr, page->objects) {
if (!test_bit(slab_index(p, s, addr), map)) {
- pr_err("INFO: Object 0x%p @offset=%tu\n", p, p - addr);
+ pr_err("INFO: Object 0x%px @offset=%tu\n", p, p - addr);
print_tracking(s, p);
}
}
--
2.18.0
reply other threads:[~2019-08-08 14:28 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190808142843.32151-1-miles.chen@mediatek.com \
--to=miles.chen@mediatek.com \
--cc=akpm@linux-foundation.org \
--cc=cl@linux.com \
--cc=iamjoonsoo.kim@lge.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mediatek@lists.infradead.org \
--cc=linux-mm@kvack.org \
--cc=penberg@kernel.org \
--cc=rientjes@google.com \
--cc=wsd_upstream@mediatek.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).