The patch titled
Subject: kasan: improve double-free report format
has been added to the -mm tree. Its filename is
kasan-improve-double-free-report-format.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kasan-improve-double-free-report-format.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kasan-improve-double-free-report-format.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: kasan: improve double-free report format
Changes double-free report header from:
BUG: Double free or freeing an invalid pointer
Unexpected shadow byte: 0xFB
to:
BUG: KASAN: double-free or invalid-free in kmalloc_oob_left+0xe5/0xef
This makes a bug uniquely identifiable by the first report line.
To account for removing of the unexpected shadow value, print shadow
bytes at the end of the report as in reports for other kinds of bugs.
Link: http://lkml.kernel.org/r/20170302134851.101218-9-andreyknvl@xxxxxxxxxx
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Acked-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/kasan/kasan.c | 3 ++-
mm/kasan/kasan.h | 2 +-
mm/kasan/report.c | 30 ++++++++++++++----------------
3 files changed, 17 insertions(+), 18 deletions(-)
diff -puN mm/kasan/kasan.c~kasan-improve-double-free-report-format mm/kasan/kasan.c
--- a/mm/kasan/kasan.c~kasan-improve-double-free-report-format
+++ a/mm/kasan/kasan.c
@@ -577,7 +577,8 @@ bool kasan_slab_free(struct kmem_cache *
shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(object));
if (shadow_byte < 0 || shadow_byte >= KASAN_SHADOW_SCALE_SIZE) {
- kasan_report_double_free(cache, object, shadow_byte);
+ kasan_report_double_free(cache, object,
+ __builtin_return_address(1));
return true;
}
diff -puN mm/kasan/kasan.h~kasan-improve-double-free-report-format mm/kasan/kasan.h
--- a/mm/kasan/kasan.h~kasan-improve-double-free-report-format
+++ a/mm/kasan/kasan.h
@@ -104,7 +104,7 @@ static inline bool kasan_report_enabled(
void kasan_report(unsigned long addr, size_t size,
bool is_write, unsigned long ip);
void kasan_report_double_free(struct kmem_cache *cache, void *object,
- s8 shadow);
+ void *ip);
#if defined(CONFIG_SLAB) || defined(CONFIG_SLUB)
void quarantine_put(struct kasan_free_meta *info, struct kmem_cache *cache);
diff -puN mm/kasan/report.c~kasan-improve-double-free-report-format mm/kasan/report.c
--- a/mm/kasan/report.c~kasan-improve-double-free-report-format
+++ a/mm/kasan/report.c
@@ -241,22 +241,8 @@ static void describe_object(struct kmem_
describe_object_addr(cache, object, addr);
}
-void kasan_report_double_free(struct kmem_cache *cache, void *object,
- s8 shadow)
-{
- unsigned long flags;
-
- kasan_start_report(&flags);
- pr_err("BUG: Double free or freeing an invalid pointer\n");
- pr_err("Unexpected shadow byte: 0x%hhX\n", shadow);
- dump_stack();
- describe_object(cache, object, NULL);
- kasan_end_report(&flags);
-}
-
-static void print_address_description(struct kasan_access_info *info)
+static void print_address_description(void *addr)
{
- void *addr = (void *)info->access_addr;
struct page *page = addr_to_page(addr);
dump_stack();
@@ -331,6 +317,18 @@ static void print_shadow_for_address(con
}
}
+void kasan_report_double_free(struct kmem_cache *cache, void *object,
+ void *ip)
+{
+ unsigned long flags;
+
+ kasan_start_report(&flags);
+ pr_err("BUG: KASAN: double-free or invalid-free in %pS\n", ip);
+ print_address_description(object);
+ print_shadow_for_address(object);
+ kasan_end_report(&flags);
+}
+
static void kasan_report_error(struct kasan_access_info *info)
{
unsigned long flags;
@@ -342,7 +340,7 @@ static void kasan_report_error(struct ka
if (!addr_has_shadow(info)) {
dump_stack();
} else {
- print_address_description(info);
+ print_address_description((void *)info->access_addr);
print_shadow_for_address(info->first_bad_addr);
}
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
kasan-introduce-helper-functions-for-determining-bug-type.patch
kasan-unify-report-headers.patch
kasan-change-allocation-and-freeing-stack-traces-headers.patch
kasan-simplify-address-description-logic.patch
kasan-change-report-header.patch
kasan-improve-slab-object-description.patch
kasan-print-page-description-after-stacks.patch
kasan-improve-double-free-report-format.patch
kasan-separate-report-parts-by-empty-lines.patch
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