[tip:x86/asm] x86/ia32-compat: Fix CLONE_SETTLS bitness of copy_thread()

[tip-bot for Andy Lutomirski <tipbot@zytor.com>]

Commit-ID:  72c6fb4f74b6b3797f5b1abd6944d7a1d2adbf04
Gitweb:     http://git.kernel.org/tip/72c6fb4f74b6b3797f5b1abd6944d7a1d2adbf04
Author:     Andy Lutomirski <luto@amacapital.net>
AuthorDate: Tue, 24 Feb 2015 16:01:39 -0800
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 25 Feb 2015 08:27:50 +0100

x86/ia32-compat: Fix CLONE_SETTLS bitness of copy_thread()

CLONE_SETTLS is expected to write a TLS entry in the GDT for
32-bit callers and to set FSBASE for 64-bit callers.

The correct check is is_ia32_task(), which returns true in the
context of a 32-bit syscall.  TIF_IA32 is set if the task itself
has a 32-bit personality, which is not the same thing.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Link: http://lkml.kernel.org/r/45e2d0d695393d76406a0c7225b82c76223e0cc5.1424822291.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/process_64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 5a2c029..936d434 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -207,7 +207,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
 	 */
 	if (clone_flags & CLONE_SETTLS) {
 #ifdef CONFIG_IA32_EMULATION
-		if (test_thread_flag(TIF_IA32))
+		if (is_ia32_task())
 			err = do_set_thread_area(p, -1,
 				(struct user_desc __user *)childregs->si, 0);
 		else