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Commit aa2efd5e authored by Daniel Thompson's avatar Daniel Thompson Committed by Linus Torvalds
Browse files

mm/slub.c: trace free objects at KERN_INFO 

Currently when trace is enabled (e.g.  slub_debug=T,kmalloc-128 ) the
trace messages are mostly output at KERN_INFO.  However the trace code
also calls print_section() to hexdump the head of a free object.  This
is hard coded to use KERN_ERR, meaning the console is deluged with trace
messages even if we've asked for quiet.

Fix this the obvious way but adding a level parameter to
print_section(), allowing calls from the trace code to use the same
trace level as other trace messages.

Link: http://lkml.kernel.org/r/20170113154850.518-1-daniel.thompson@linaro.org


Signed-off-by: default avatarDaniel Thompson <daniel.thompson@linaro.org>
Acked-by: default avatarChristoph Lameter <cl@linux.com>
Acked-by: default avatarDavid Rientjes <rientjes@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 15a77c6f

mm/slub.c

+13 −10
Original line number Diff line number Diff line
@@ -496,10 +496,11 @@ static inline int check_valid_pointer(struct kmem_cache *s, 
	return 1;

}



static void print_section(char *text, u8 *addr, unsigned int length)

static void print_section(char *level, char *text, u8 *addr,

			  unsigned int length)

{

	metadata_access_enable();

	print_hex_dump(KERN_ERR, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,

	print_hex_dump(level, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,

			length, 1);

	metadata_access_disable();

}
@@ -636,14 +637,15 @@ static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p) 
	       p, p - addr, get_freepointer(s, p));



	if (s->flags & SLAB_RED_ZONE)

		print_section("Redzone ", p - s->red_left_pad, s->red_left_pad);

		print_section(KERN_ERR, "Redzone ", p - s->red_left_pad,

			      s->red_left_pad);

	else if (p > addr + 16)

		print_section("Bytes b4 ", p - 16, 16);

		print_section(KERN_ERR, "Bytes b4 ", p - 16, 16);



	print_section("Object ", p, min_t(unsigned long, s->object_size,

				PAGE_SIZE));

	print_section(KERN_ERR, "Object ", p,

		      min_t(unsigned long, s->object_size, PAGE_SIZE));

	if (s->flags & SLAB_RED_ZONE)

		print_section("Redzone ", p + s->object_size,

		print_section(KERN_ERR, "Redzone ", p + s->object_size,

			s->inuse - s->object_size);



	if (s->offset)
@@ -658,7 +660,8 @@ static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p) 


	if (off != size_from_object(s))

		/* Beginning of the filler is the free pointer */

		print_section("Padding ", p + off, size_from_object(s) - off);

		print_section(KERN_ERR, "Padding ", p + off,

			      size_from_object(s) - off);



	dump_stack();

}
@@ -820,7 +823,7 @@ static int slab_pad_check(struct kmem_cache *s, struct page *page) 
		end--;



	slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);

	print_section("Padding ", end - remainder, remainder);

	print_section(KERN_ERR, "Padding ", end - remainder, remainder);



	restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);

	return 0;
@@ -973,7 +976,7 @@ static void trace(struct kmem_cache *s, struct page *page, void *object, 
			page->freelist);



		if (!alloc)

			print_section("Object ", (void *)object,

			print_section(KERN_INFO, "Object ", (void *)object,

					s->object_size);



		dump_stack();