linux-kernel - [PATCH] x32: make sure TS_COMPAT is cleared for x32 tasks

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Message-Id: <1330230338-25077-1-git-send-email-bobbypowers@gmail.com>
Date:	Sat, 25 Feb 2012 23:25:38 -0500
From:	Bobby Powers <bobbypowers@...il.com>
To:	linux-kernel@...r.kernel.org
Cc:	hpa@...or.com, mingo@...hat.com, tglx@...utronix.de,
	x86@...nel.org, hjl.tools@...il.com,
	Bobby Powers <bobbypowers@...il.com>
Subject: [PATCH] x32: make sure TS_COMPAT is cleared for x32 tasks

If a process has a non-x32 ia32 personality and changes to x32, the
process would keep its TS_COMPAT flag. x32 uses the presence of the
x32 flag on a syscall to determine compat status, so make sure
TS_COMPAT is cleared.

Signed-off-by: Bobby Powers <bobbypowers@...il.com>
---
 arch/x86/kernel/process_64.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index e9ec8f1..a465973 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -539,6 +539,9 @@ void set_personality_ia32(bool x32)
 		clear_thread_flag(TIF_IA32);
 		set_thread_flag(TIF_X32);
 		current->personality &= ~READ_IMPLIES_EXEC;
+		/* is_compat_task() uses the presence of the x32
+		   syscall bit flag to determine compat status */
+		current_thread_info()->status &= ~TS_COMPAT;
 	} else {
 		set_thread_flag(TIF_IA32);
 		clear_thread_flag(TIF_X32);
-- 
1.7.7.6

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