[3.19.y-ckt stable] Patch "dma-debug: switch check from _text to _stext" has been added to the 3.19.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    dma-debug: switch check from _text to _stext

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt14.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

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

>From 085a27e5f56e22c7484a78e86a2dc19042765e81 Mon Sep 17 00:00:00 2001
From: Laura Abbott <labbott at fedoraproject.org>
Date: Thu, 14 Jan 2016 15:16:50 -0800
Subject: dma-debug: switch check from _text to _stext

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@redhat.com>

Signed-off-by: Laura Abbott <labbott at fedoraproject.org>
Reviewed-by: Kees Cook <keescook at chromium.org>
Cc: Russell King <linux at arm.linux.org.uk>
Cc: Arnd Bergmann <arnd at arndb.de>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 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 340776a..57f452f 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -1181,7 +1181,7 @@ 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);
 }
--
1.9.1