@@ -181,7 +181,7 @@ SLUB Debug output
Here is a sample of slub debug output::
====================================================================
- BUG kmalloc-8: Redzone overwritten
+ BUG kmalloc-8: Right Redzone overwritten
--------------------------------------------------------------------
INFO: 0xc90f6d28-0xc90f6d2b. First byte 0x00 instead of 0xcc
@@ -189,10 +189,10 @@ Here is a sample of slub debug output::
INFO: Object 0xc90f6d20 @offset=3360 fp=0xc90f6d58
INFO: Allocated in get_modalias+0x61/0xf5 age=53 cpu=1 pid=554
- Bytes b4 0xc90f6d10: 00 00 00 00 00 00 00 00 5a 5a 5a 5a 5a 5a 5a 5a ........ZZZZZZZZ
- Object 0xc90f6d20: 31 30 31 39 2e 30 30 35 1019.005
- Redzone 0xc90f6d28: 00 cc cc cc .
- Padding 0xc90f6d50: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ
+ Bytes b4 (0xc90f6d10): 00 00 00 00 00 00 00 00 5a 5a 5a 5a 5a 5a 5a 5a ........ZZZZZZZZ
+ Object (0xc90f6d20): 31 30 31 39 2e 30 30 35 1019.005
+ Redzone (0xc90f6d28): 00 cc cc cc .
+ Padding (0xc90f6d50): 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ
[<c010523d>] dump_trace+0x63/0x1eb
[<c01053df>] show_trace_log_lvl+0x1a/0x2f
@@ -712,15 +712,15 @@ static void print_trailer(struct kmem_ca
p, p - addr, get_freepointer(s, p));
if (s->flags & SLAB_RED_ZONE)
- print_section(KERN_ERR, "Redzone ", p - 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(KERN_ERR, "Bytes b4 ", p - 16, 16);
- print_section(KERN_ERR, "Object ", p,
+ print_section(KERN_ERR, "Object ", p,
min_t(unsigned int, s->object_size, PAGE_SIZE));
if (s->flags & SLAB_RED_ZONE)
- print_section(KERN_ERR, "Redzone ", p + s->object_size,
+ print_section(KERN_ERR, "Redzone ", p + s->object_size,
s->inuse - s->object_size);
off = get_info_end(s);
@@ -732,7 +732,7 @@ static void print_trailer(struct kmem_ca
if (off != size_from_object(s))
/* Beginning of the filler is the free pointer */
- print_section(KERN_ERR, "Padding ", p + off,
+ print_section(KERN_ERR, "Padding ", p + off,
size_from_object(s) - off);
dump_stack();
@@ -909,11 +909,11 @@ static int check_object(struct kmem_cach
u8 *endobject = object + s->object_size;
if (s->flags & SLAB_RED_ZONE) {
- if (!check_bytes_and_report(s, page, object, "Redzone",
+ if (!check_bytes_and_report(s, page, object, "Left Redzone",
object - s->red_left_pad, val, s->red_left_pad))
return 0;
- if (!check_bytes_and_report(s, page, object, "Redzone",
+ if (!check_bytes_and_report(s, page, object, "Right Redzone",
endobject, val, s->inuse - s->object_size))
return 0;
} else {
@@ -928,7 +928,7 @@ static int check_object(struct kmem_cach
if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
(!check_bytes_and_report(s, page, p, "Poison", p,
POISON_FREE, s->object_size - 1) ||
- !check_bytes_and_report(s, page, p, "Poison",
+ !check_bytes_and_report(s, page, p, "End Poison",
p + s->object_size - 1, POISON_END, 1)))
return 0;
/*
The patch titled Subject: mm/slub: clarify verification reporting has been removed from the -mm tree. Its filename was mm-slub-clarify-verification-reporting.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Kees Cook <keescook@chromium.org> Subject: mm/slub: clarify verification reporting Patch series "Actually fix freelist pointer vs redzoning", v4. This fixes redzoning vs the freelist pointer (both for middle-position and very small caches). Both are "theoretical" fixes, in that I see no evidence of such small-sized caches actually be used in the kernel, but that's no reason to let the bugs continue to exist, especially since people doing local development keep tripping over it. :) This patch (of 3): Instead of repeating "Redzone" and "Poison", clarify which sides of those zones got tripped. Additionally fix column alignment in the trailer. Before: BUG test (Tainted: G B ): Redzone overwritten ... Redzone (____ptrval____): bb bb bb bb bb bb bb bb ........ Object (____ptrval____): f6 f4 a5 40 1d e8 ...@.. Redzone (____ptrval____): 1a aa .. Padding (____ptrval____): 00 00 00 00 00 00 00 00 ........ After: BUG test (Tainted: G B ): Right Redzone overwritten ... Redzone (____ptrval____): bb bb bb bb bb bb bb bb ........ Object (____ptrval____): f6 f4 a5 40 1d e8 ...@.. Redzone (____ptrval____): 1a aa .. Padding (____ptrval____): 00 00 00 00 00 00 00 00 ........ The earlier commits that slowly resulted in the "Before" reporting were: d86bd1bece6f ("mm/slub: support left redzone") ffc79d288000 ("slub: use print_hex_dump") 2492268472e7 ("SLUB: change error reporting format to follow lockdep loosely") Link: https://lkml.kernel.org/r/20210608183955.280836-1-keescook@chromium.org Link: https://lkml.kernel.org/r/20210608183955.280836-2-keescook@chromium.org Link: https://lore.kernel.org/lkml/cfdb11d7-fb8e-e578-c939-f7f5fb69a6bd@suse.cz/ Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Marco Elver <elver@google.com> Cc: "Lin, Zhenpeng" <zplin@psu.edu> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Roman Gushchin <guro@fb.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> --- Documentation/vm/slub.rst | 10 +++++----- mm/slub.c | 14 +++++++------- 2 files changed, 12 insertions(+), 12 deletions(-)