[PATCH 3.16.y-ckt 108/180] dma-debug: switch check from _text to _stext

[Luis Henriques]

3.16.7-ckt24 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Laura Abbott <labbott@xxxxxxxxxxxxxxxxx>

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: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
 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 1c741f900028..1cbfc16d0b37 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -1165,7 +1165,7 @@ 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);
 }