From: Adrian Bunk <bunk@stusta.de>
Date: Sun, 9 Oct 2011 13:47:26 +0000 (+0300)
Subject: x86, vsyscall: Use better error message on bad pointers
X-Git-Tag: next-20111011~22^2^2
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=ef4f84e9187dcd017ea0ab3976af4d3ba806ed95;p=karo-tx-linux.git

x86, vsyscall: Use better error message on bad pointers

At least some UML versions run into this and need
vsyscall=native for now.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: Andrew Lutomirski <luto@mit.edu>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Arjan van de Ven <arjan@infradead.org>
Link: http://lkml.kernel.org/r/20111009134725.GD4586@localhost.pp.htv.fi
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
index 18ae83dd1cd7..4ab7e322e0e6 100644
--- a/arch/x86/kernel/vsyscall_64.c
+++ b/arch/x86/kernel/vsyscall_64.c
@@ -206,7 +206,7 @@ bool emulate_vsyscall(struct pt_regs *regs, unsigned long address)
 		 * vsyscalls harder, generate SIGSEGV here as well.
 		 */
 		warn_bad_vsyscall(KERN_INFO, regs,
-				  "vsyscall fault (exploit attempt?)");
+				  "vsyscall fault (exploit attempt?) - if this is a legitimate program boot with vsyscall=native (read kernel-parameters.txt for the security implications)");
 		goto sigsegv;
 	}