lkml.org 
[lkml]   [2015]   [Sep]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH V2 3/4] mm/kasan: Don't use kasan shadow pointer in generic functions
Date
We can't use generic functions like print_hex_dump to access kasan
shadow region. This require us to setup another kasan shadow region
for the address passed (kasan shadow address). Some architectures won't
be able to do that. Hence make a copy of the shadow region row and
pass that to generic functions.

Reviewed-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
mm/kasan/report.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index d269f2087faf..c5367089703c 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -164,14 +164,20 @@ static void print_shadow_for_address(const void *addr)
for (i = -SHADOW_ROWS_AROUND_ADDR; i <= SHADOW_ROWS_AROUND_ADDR; i++) {
const void *kaddr = kasan_shadow_to_mem(shadow_row);
char buffer[4 + (BITS_PER_LONG/8)*2];
+ char shadow_buf[SHADOW_BYTES_PER_ROW];

snprintf(buffer, sizeof(buffer),
(i == 0) ? ">%p: " : " %p: ", kaddr);
-
+ /*
+ * We should not pass a shadow pointer to generic
+ * function, because generic functions may try to
+ * access kasan mapping for the passed address.
+ */
kasan_disable_current();
+ memcpy(shadow_buf, shadow_row, SHADOW_BYTES_PER_ROW);
print_hex_dump(KERN_ERR, buffer,
DUMP_PREFIX_NONE, SHADOW_BYTES_PER_ROW, 1,
- shadow_row, SHADOW_BYTES_PER_ROW, 0);
+ shadow_buf, SHADOW_BYTES_PER_ROW, 0);
kasan_enable_current();

if (row_is_guilty(shadow_row, shadow))
--
2.5.0


\
 
 \ /
  Last update: 2015-09-07 10:41    [W:0.044 / U:0.568 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site