linux-kernel - [PATCH] x86: text_poke, check if text

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Message-Id: <1462777621-10206-1-git-send-email-jslaby@suse.cz>
Date:	Mon,  9 May 2016 09:07:01 +0200
From:	Jiri Slaby <jslaby@...e.cz>
To:	mingo@...hat.com
Cc:	linux-kernel@...r.kernel.org, Jiri Slaby <jslaby@...e.cz>,
	Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org
Subject: [PATCH] x86: text_poke, check if text_mutex is held

This is required by the function, so use lockdep (if available) to
check the dependency.

Signed-off-by: Jiri Slaby <jslaby@...e.cz>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: x86@...nel.org
---
 arch/x86/kernel/alternative.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 5cb272a7a5a3..233b718be213 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -694,6 +694,8 @@ void *text_poke(void *addr, const void *opcode, size_t len)
 	struct page *pages[2];
 	int i;
 
+	lockdep_assert_held(&text_mutex);
+
 	if (!core_kernel_text((unsigned long)addr)) {
 		pages[0] = vmalloc_to_page(addr);
 		pages[1] = vmalloc_to_page(addr + PAGE_SIZE);
-- 
2.8.2