Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal

Pull assorted signal-related fixes from Al Viro:
 "uml regression fix (braino in sys_execve() patch) + a bunch of fucked
  sigaltstack-on-rt_sigreturn uses, similar to sparc64 fix that went in
  through davem's tree.  m32r horrors not included - that one's waiting
  for maintainer."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
  microblaze: rt_sigreturn is too trigger-happy about sigaltstack errors
  score: do_sigaltstack() expects a userland pointer...
  sh64: fix altstack switching on sigreturn
  openrisk: fix altstack switching on sigreturn
  um: get_safe_registers() should be done in flush_thread(), not start_thread()

5 files changed, 9 insertions, 15 deletions

diff --git a/arch/microblaze/kernel/signal.c b/arch/microblaze/kernel/signal.c
index 3847e5b9c60..3903e3d11f5 100644
--- a/arch/microblaze/kernel/signal.c
+++ b/arch/microblaze/kernel/signal.c
@@ -111,7 +111,7 @@ asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
 
 	/* It is more difficult to avoid calling this function than to
 	 call it and ignore errors. */
-	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->r1))
+	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->r1) == -EFAULT)
 		goto badframe;
 
 	return rval;
diff --git a/arch/openrisc/kernel/signal.c b/arch/openrisc/kernel/signal.c
index 30110297f4f..ddedc8a7786 100644
--- a/arch/openrisc/kernel/signal.c
+++ b/arch/openrisc/kernel/signal.c
@@ -84,7 +84,6 @@ asmlinkage long _sys_rt_sigreturn(struct pt_regs *regs)
 {
 	struct rt_sigframe *frame = (struct rt_sigframe __user *)regs->sp;
 	sigset_t set;
-	stack_t st;
 
 	/*
 	 * Since we stacked the signal on a dword boundary,
@@ -104,11 +103,10 @@ asmlinkage long _sys_rt_sigreturn(struct pt_regs *regs)
 	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
 		goto badframe;
 
-	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, regs->sp);
+	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
+		goto badframe;
 
 	return regs->gpr[11];
 
diff --git a/arch/score/kernel/signal.c b/arch/score/kernel/signal.c
index c268bbf8b41..02353bde92d 100644
--- a/arch/score/kernel/signal.c
+++ b/arch/score/kernel/signal.c
@@ -148,7 +148,6 @@ score_rt_sigreturn(struct pt_regs *regs)
 {
 	struct rt_sigframe __user *frame;
 	sigset_t set;
-	stack_t st;
 	int sig;
 
 	/* Always make any pending restarted system calls return -EINTR */
@@ -168,12 +167,10 @@ score_rt_sigreturn(struct pt_regs *regs)
 	else if (sig)
 		force_sig(sig, current);
 
-	if (__copy_from_user(&st, &frame->rs_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((stack_t __user *)&st, NULL, regs->regs[0]);
+	if (do_sigaltstack(&frame->rs_uc.uc_stack, NULL, regs->regs[0]) == -EFAULT)
+		goto badframe;
 	regs->is_syscall = 0;
 
 	__asm__ __volatile__(
diff --git a/arch/sh/kernel/signal_64.c b/arch/sh/kernel/signal_64.c
index 23853814bd1..d867cd95a62 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;
 
diff --git a/arch/um/kernel/exec.c b/arch/um/kernel/exec.c
index 3a8ece7d09c..0d7103c9eff 100644
--- a/arch/um/kernel/exec.c
+++ b/arch/um/kernel/exec.c
@@ -32,13 +32,14 @@ void flush_thread(void)
 		       "err = %d\n", ret);
 		force_sig(SIGKILL, current);
 	}
+	get_safe_registers(current_pt_regs()->regs.gp,
+			   current_pt_regs()->regs.fp);
 
 	__switch_mm(&current->mm->context.id);
 }
 
 void start_thread(struct pt_regs *regs, unsigned long eip, unsigned long esp)
 {
-	get_safe_registers(regs->regs.gp, regs->regs.fp);
 	PT_REGS_IP(regs) = eip;
 	PT_REGS_SP(regs) = esp;
 	current->ptrace &= ~PT_DTRACE;