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Fri, 09 Aug 2019 09:08:37 +0800 Received: from mtkcas08.mediatek.inc (172.21.101.126) by mtkmbs06n1.mediatek.inc (172.21.101.129) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Fri, 9 Aug 2019 09:08:37 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkcas08.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1395.4 via Frontend Transport; Fri, 9 Aug 2019 09:08:37 +0800 From: To: Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton CC: , , , , Miles Chen , "Tobin C . Harding" , Kees Cook Subject: [RFC PATCH v2] mm: slub: print kernel addresses in slub debug messages Date: Fri, 9 Aug 2019 09:08:37 +0800 Message-ID: <20190809010837.24166-1-miles.chen@mediatek.com> X-Mailer: git-send-email 2.18.0 MIME-Version: 1.0 X-MTK: N X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: X-Virus-Scanned: ClamAV using ClamSMTP From: Miles Chen 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 with %pK, 3. print 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 Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Cc: Andrew Morton Cc: Tobin C. Harding Cc: Kees Cook Signed-off-by: Miles Chen --- 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); } }