From 9dc87c7b5b0a2db407e086f45cf08ca78208cc16 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Thu, 20 Sep 2012 16:38:34 -0400
Subject: sh64: fix altstack switching on sigreturn

incidentally, declaring a local variable as __user (!) to make
sparse STFU is really sick.  Especially since sparse had been
100% right - it *is* a bug.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/sh/kernel/signal_64.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

(limited to 'arch/sh')

diff --git a/arch/sh/kernel/signal_64.c b/arch/sh/kernel/signal_64.c
index 23853814bd17..d867cd95a622 100644
--- a/arch/sh/kernel/signal_64.c
+++ b/arch/sh/kernel/signal_64.c
@@ -347,7 +347,6 @@ asmlinkage int sys_rt_sigreturn(unsigned long r2, unsigned long r3,
 {
 	struct rt_sigframe __user *frame = (struct rt_sigframe __user *) (long) REF_REG_SP;
 	sigset_t set;
-	stack_t __user st;
 	long long ret;
 
 	/* Always make any pending restarted system calls return -EINTR */
@@ -365,11 +364,10 @@ asmlinkage int sys_rt_sigreturn(unsigned long r2, unsigned long r3,
 		goto badframe;
 	regs->pc -= 4;
 
-	if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st)))
-		goto badframe;
 	/* It is more difficult to avoid calling this function than to
 	   call it and ignore errors.  */
-	do_sigaltstack(&st, NULL, REF_REG_SP);
+	if (do_sigaltstack(&frame->uc.uc_stack, NULL, REF_REG_SP) == -EFAULT)
+		goto badframe;
 
 	return (int) ret;
 
-- 
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