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From: Laura Abbott <labbott@fedoraproject.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Laura Abbott <labbott@fedoraproject.org>,
	Russell King <linux@arm.linux.org.uk>,
	Kees Cook <keescook@chromium.org>,
	linux-kernel@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>
Subject: [PATCH] dma-debug: Switch check from _text to _stext
Date: Mon,  4 Jan 2016 10:48:12 -0800	[thread overview]
Message-ID: <1451933292-1209-1-git-send-email-labbott@fedoraproject.org> (raw)

>From 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.

Signed-off-by: Laura Abbott <labbott@fedoraproject.org>
---
Came out of https://lkml.kernel.org/g/<567B1176.4000106@redhat.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 d34bd24..4a1515f 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);
 }
-- 
2.5.0


             reply	other threads:[~2016-01-04 18:48 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-04 18:48 Laura Abbott [this message]
2016-01-04 19:15 ` Kees Cook

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