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

Pull first series of signal handling cleanups from Al Viro:
 "This is just the first part of the queue (about a half of it);
  assorted fixes all over the place in signal handling.

  This one ends with all sigsuspend() implementations switched to
  generic one (->saved_sigmask-based).

  With this, a bunch of assorted old buglets are fixed and most of the
  missing bits of NOTIFY_RESUME hookup are in place.  Two more fixes sit
  in arm and um trees respectively, and there's a couple of broken ones
  that need obvious fixes - parisc and avr32 check TIF_NOTIFY_RESUME
  only on one of two codepaths; fixes for that will happen in the next
  series"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (55 commits)
  unicore32: if there's no handler we need to restore sigmask, syscall or no syscall
  xtensa: add handling of TIF_NOTIFY_RESUME
  microblaze: drop 'oldset' argument of do_notify_resume()
  microblaze: handle TIF_NOTIFY_RESUME
  score: add handling of NOTIFY_RESUME to do_notify_resume()
  m68k: add TIF_NOTIFY_RESUME and handle it.
  sparc: kill ancient comment in sparc_sigaction()
  h8300: missing checks of __get_user()/__put_user() return values
  frv: missing checks of __get_user()/__put_user() return values
  cris: missing checks of __get_user()/__put_user() return values
  powerpc: missing checks of __get_user()/__put_user() return values
  sh: missing checks of __get_user()/__put_user() return values
  sparc: missing checks of __get_user()/__put_user() return values
  avr32: struct old_sigaction is never used
  m32r: struct old_sigaction is never used
  xtensa: xtensa_sigaction doesn't exist
  alpha: tidy signal delivery up
  score: don't open-code force_sigsegv()
  cris: don't open-code force_sigsegv()
  blackfin: don't open-code force_sigsegv()
  ...

Author: torvalds

arch/alpha/kernel/signal.c

@@ -34,9 +34,6 @@
 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
 
 asmlinkage void ret_from_sys_call(void);
-static void do_signal(struct pt_regs *, struct switch_stack *,
-		      unsigned long, unsigned long);
-
 
 /*
  * The OSF/1 sigprocmask calling sequence is different from the
@@ -121,17 +118,8 @@ SYSCALL_DEFINE5(rt_sigaction, int, sig, const struct sigaction __user *, act,
 SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
 {
 	sigset_t blocked;
-
-	current->saved_sigmask = current->blocked;
-
-	mask &= _BLOCKABLE;
 	siginitset(&blocked, mask);
-	set_current_blocked(&blocked);
-
-	current->state = TASK_INTERRUPTIBLE;
-	schedule();
-	set_thread_flag(TIF_RESTORE_SIGMASK);
-	return -ERESTARTNOHAND;
+	return sigsuspend(&blocked);
 }
 
 asmlinkage int
@@ -376,11 +364,11 @@ setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
 	oldsp = rdusp();
 	frame = get_sigframe(ka, oldsp, sizeof(*frame));
 	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
-		goto give_sigsegv;
+		return -EFAULT;
 
 	err |= setup_sigcontext(&frame->sc, regs, sw, set->sig[0], oldsp);
 	if (err)
-		goto give_sigsegv;
+		return -EFAULT;
 
 	/* Set up to return from userspace.  If provided, use a stub
 	   already in userspace.  */
@@ -396,7 +384,7 @@ setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
 
 	/* Check that everything was written properly.  */
 	if (err)
-		goto give_sigsegv;
+		return err;
 
 	/* "Return" to the handler */
 	regs->r26 = r26;
@@ -410,12 +398,7 @@ setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
 	printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
 		current->comm, current->pid, frame, regs->pc, regs->r26);
 #endif
-
 	return 0;
-
-give_sigsegv:
-	force_sigsegv(sig, current);
-	return -EFAULT;
 }
 
 static int
@@ -428,7 +411,7 @@ setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 	oldsp = rdusp();
 	frame = get_sigframe(ka, oldsp, sizeof(*frame));
 	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
-		goto give_sigsegv;
+		return -EFAULT;
 
 	err |= copy_siginfo_to_user(&frame->info, info);
 
@@ -443,7 +426,7 @@ setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 				set->sig[0], oldsp);
 	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 	if (err)
-		goto give_sigsegv;
+		return -EFAULT;
 
 	/* Set up to return from userspace.  If provided, use a stub
 	   already in userspace.  */
@@ -459,7 +442,7 @@ setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 	}
 
 	if (err)
-		goto give_sigsegv;
+		return -EFAULT;
 
 	/* "Return" to the handler */
 	regs->r26 = r26;
@@ -475,31 +458,37 @@ setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 #endif
 
 	return 0;
-
-give_sigsegv:
-	force_sigsegv(sig, current);
-	return -EFAULT;
 }
 
 
 /*
  * OK, we're invoking a handler.
  */
-static inline int
+static inline void
 handle_signal(int sig, struct k_sigaction *ka, siginfo_t *info,
-	      sigset_t *oldset, struct pt_regs * regs, struct switch_stack *sw)
+	      struct pt_regs * regs, struct switch_stack *sw)
 {
+	sigset_t *oldset = &current->blocked;
 	int ret;
 
+	if (test_thread_flag(TIF_RESTORE_SIGMASK))
+		oldset = &current->saved_sigmask;
+
 	if (ka->sa.sa_flags & SA_SIGINFO)
 		ret = setup_rt_frame(sig, ka, info, oldset, regs, sw);
 	else
 		ret = setup_frame(sig, ka, oldset, regs, sw);
 
-	if (ret == 0)
-		block_sigmask(ka, sig);
-
-	return ret;
+	if (ret) {
+		force_sigsegv(sig, current);
+		return;
+	}
+	block_sigmask(ka, sig);
+	/* A signal was successfully delivered, and the
+	   saved sigmask was stored on the signal frame,
+	   and will be restored by sigreturn.  So we can
+	   simply clear the restore sigmask flag.  */
+	clear_thread_flag(TIF_RESTORE_SIGMASK);
 }
 
 static inline void
@@ -547,12 +536,6 @@ do_signal(struct pt_regs * regs, struct switch_stack * sw,
 	int signr;
 	unsigned long single_stepping = ptrace_cancel_bpt(current);
 	struct k_sigaction ka;
-	sigset_t *oldset;
-
-	if (test_thread_flag(TIF_RESTORE_SIGMASK))
-		oldset = &current->saved_sigmask;
-	else
-		oldset = &current->blocked;
 
 	/* This lets the debugger run, ... */
 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
@@ -564,14 +547,7 @@ do_signal(struct pt_regs * regs, struct switch_stack * sw,
 		/* Whee!  Actually deliver the signal.  */
 		if (r0)
 			syscall_restart(r0, r19, regs, &ka);
-		if (handle_signal(signr, &ka, &info, oldset, regs, sw) == 0) {
-			/* A signal was successfully delivered, and the
-			   saved sigmask was stored on the signal frame,
-			   and will be restored by sigreturn.  So we can
-			   simply clear the restore sigmask flag.  */
-			if (test_thread_flag(TIF_RESTORE_SIGMASK))
-				clear_thread_flag(TIF_RESTORE_SIGMASK);
-		}
+		handle_signal(signr, &ka, &info, regs, sw);
 		if (single_stepping) 
 			ptrace_set_bpt(current); /* re-set bpt */
 		return;
@@ -596,10 +572,8 @@ do_signal(struct pt_regs * regs, struct switch_stack * sw,
 	}
 
 	/* If there's no signal to deliver, we just restore the saved mask.  */
-	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
-		clear_thread_flag(TIF_RESTORE_SIGMASK);
-		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
-	}
+	if (test_and_clear_thread_flag(TIF_RESTORE_SIGMASK))
+		set_current_blocked(&current->saved_sigmask);
 
 	if (single_stepping)
 		ptrace_set_bpt(current);	/* re-set breakpoint */
@@ -610,7 +584,7 @@ do_notify_resume(struct pt_regs *regs, struct switch_stack *sw,
 		 unsigned long thread_info_flags,
 		 unsigned long r0, unsigned long r19)
 {
-	if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
+	if (thread_info_flags & _TIF_SIGPENDING)
 		do_signal(regs, sw, r0, r19);
 
 	if (thread_info_flags & _TIF_NOTIFY_RESUME) {

arch/arm/kernel/signal.c

@@ -67,17 +67,8 @@ const unsigned long syscall_restart_code[2] = {
 asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask)
 {
 	sigset_t blocked;
-
-	current->saved_sigmask = current->blocked;
-
-	mask &= _BLOCKABLE;
 	siginitset(&blocked, mask);
-	set_current_blocked(&blocked);
-
-	current->state = TASK_INTERRUPTIBLE;
-	schedule();
-	set_restore_sigmask();
-	return -ERESTARTNOHAND;
+	return sigsuspend(&blocked);
 }
 
 asmlinkage int 

arch/avr32/include/asm/signal.h

@@ -115,13 +115,6 @@ typedef unsigned long sigset_t;
 #include <asm-generic/signal-defs.h>
 
 #ifdef __KERNEL__
-struct old_sigaction {
-	__sighandler_t sa_handler;
-	old_sigset_t sa_mask;
-	unsigned long sa_flags;
-	__sigrestore_t sa_restorer;
-};
-
 struct sigaction {
 	__sighandler_t sa_handler;
 	unsigned long sa_flags;

arch/avr32/kernel/signal.c

@@ -77,6 +77,9 @@ asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
 	struct rt_sigframe __user *frame;
 	sigset_t set;
 
+	/* Always make any pending restarted system calls return -EINTR */
+	current_thread_info()->restart_block.fn = do_no_restart_syscall;
+
 	frame = (struct rt_sigframe __user *)regs->sp;
 	pr_debug("SIG return: frame = %p\n", frame);
 
@@ -87,10 +90,7 @@ asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
 		goto badframe;
 
 	sigdelsetmask(&set, ~_BLOCKABLE);
-	spin_lock_irq(&current->sighand->siglock);
-	current->blocked = set;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+	set_current_blocked(&set);
 
 	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
 		goto badframe;
@@ -238,22 +238,16 @@ handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
 	 */
 	ret |= !valid_user_regs(regs);
 
-	/*
-	 * Block the signal if we were unsuccessful.
-	 */
-	if (ret != 0 || !(ka->sa.sa_flags & SA_NODEFER)) {
-		spin_lock_irq(&current->sighand->siglock);
-		sigorsets(&current->blocked, &current->blocked,
-			  &ka->sa.sa_mask);
-		sigaddset(&current->blocked, sig);
-		recalc_sigpending();
-		spin_unlock_irq(&current->sighand->siglock);
-	}
-
-	if (ret == 0)
+	if (ret != 0) {
+		force_sigsegv(sig, current);
 		return;
+	}
 
-	force_sigsegv(sig, current);
+	/*
+	 * Block the signal if we were successful.
+	 */
+	block_sigmask(ka, sig);
+	clear_thread_flag(TIF_RESTORE_SIGMASK);
 }
 
 /*

arch/blackfin/kernel/signal.c

@@ -99,10 +99,7 @@ asmlinkage int do_rt_sigreturn(unsigned long __unused)
 		goto badframe;
 
 	sigdelsetmask(&set, ~_BLOCKABLE);
-	spin_lock_irq(&current->sighand->siglock);
-	current->blocked = set;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+	set_current_blocked(&set);
 
 	if (rt_restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
 		goto badframe;
@@ -213,9 +210,7 @@ setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t * info,
 	return 0;
 
  give_sigsegv:
-	if (sig == SIGSEGV)
-		ka->sa.sa_handler = SIG_DFL;
-	force_sig(SIGSEGV, current);
+	force_sigsegv(sig, current);
 	return -EFAULT;
 }
 
@@ -266,15 +261,9 @@ handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka,
 	/* set up the stack frame */
 	ret = setup_rt_frame(sig, ka, info, oldset, regs);
 
-	if (ret == 0) {
-		spin_lock_irq(&current->sighand->siglock);
-		sigorsets(&current->blocked, &current->blocked,
-			  &ka->sa.sa_mask);
-		if (!(ka->sa.sa_flags & SA_NODEFER))
-			sigaddset(&current->blocked, sig);
-		recalc_sigpending();
-		spin_unlock_irq(&current->sighand->siglock);
-	}
+	if (ret == 0)
+		block_sigmask(ka, sig);
+
 	return ret;
 }
 

arch/c6x/kernel/signal.c

@@ -69,6 +69,9 @@ asmlinkage int do_rt_sigreturn(struct pt_regs *regs)
 	struct rt_sigframe __user *frame;
 	sigset_t set;
 
+	/* Always make any pending restarted system calls return -EINTR */
+	current_thread_info()->restart_block.fn = do_no_restart_syscall;
+
 	/*
 	 * Since we stacked the signal on a dword boundary,
 	 * 'sp' should be dword aligned here.  If it's