From: "Aneesh Kumar K.V" aneesh.kumar@linux.vnet.ibm.com
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.
Signed-off-by: Aneesh Kumar K.V aneesh.kumar@linux.vnet.ibm.com Reviewed-by: Andrey Ryabinin ryabinin.a.a@gmail.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org (cherry picked from commit f2377d4eaab2aabe1938b3974b5b94f5ba4c7ead) Signed-off-by: Alex Shi alex.shi@linaro.org --- 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 9474364..2b30762 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))