[PATCH 3.12 132/142] dma-debug: switch check from _text to _stext

From: Jiri Slaby
Date: Wed Feb 24 2016 - 05:13:09 EST

From: Laura Abbott <labbott@xxxxxxxxxxxxxxxxx>

3.12-stable review patch. If anyone has any objections, please let me know.


commit ea535e418c01837d07b6c94e817540f50bfdadb0 upstream.

In include/asm-generic/sections.h:

* Usage guidelines:
* _text, _data: architecture specific, don't use them in
* arch-independent code
* [_stext, _etext]: contains .text.* sections, may also contain
* .rodata.*
* and/or .init.* sections

_text is not guaranteed across architectures. Architectures such as ARM
may reuse parts which are not actually text and erroneously trigger a bug.
Switch to using _stext which is guaranteed to contain text sections.

Came out of https://lkml.kernel.org/g/<567B1176.4000106@xxxxxxxxxx>

Signed-off-by: Laura Abbott <labbott@xxxxxxxxxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
lib/dma-debug.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index d87a17a819d0..eb43517bf261 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -962,7 +962,7 @@ static inline bool overlap(void *addr, unsigned long len, void *start, void *end

static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
- if (overlap(addr, len, _text, _etext) ||
+ if (overlap(addr, len, _stext, _etext) ||
overlap(addr, len, __start_rodata, __end_rodata))
err_printk(dev, NULL, "DMA-API: device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);