linux-kernel - [PATCH 5/6] x86: signal: handle_signal() should use sigprocmask()

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Message-ID: <20110411172201.GF32469@redhat.com>
Date:	Mon, 11 Apr 2011 19:22:01 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Tejun Heo <tj@...nel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Cc:	"Nikita V. Youshchenko" <nyoushchenko@...sta.com>,
	Matt Fleming <matt@...sole-pimps.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-kernel@...r.kernel.org
Subject: [PATCH 5/6] x86: signal: handle_signal() should use sigprocmask()

This is ugly, but if sigprocmask() needs retarget_shared_pending() then
handle signal should follow this logic. In theory it is newer correct to
add the new signals to current->blocked, the signal handler can sleep/etc
so we should notify other threads in case we block the pending signal and
nobody else has TIF_SIGPENDING.

Of course, this change doesn't make signals faster :/

Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---

 arch/x86/kernel/signal.c |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

--- sigprocmask/arch/x86/kernel/signal.c~5_handle_signal	2011-04-06 21:33:43.000000000 +0200
+++ sigprocmask/arch/x86/kernel/signal.c	2011-04-11 18:33:17.000000000 +0200
@@ -682,6 +682,7 @@ static int
 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 	      sigset_t *oldset, struct pt_regs *regs)
 {
+	sigset_t blocked;
 	int ret;
 
 	/* Are we from a system call? */
@@ -741,12 +742,10 @@ handle_signal(unsigned long sig, siginfo
 	 */
 	regs->flags &= ~X86_EFLAGS_TF;
 
-	spin_lock_irq(&current->sighand->siglock);
-	sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
+	blocked = ka->sa.sa_mask;
 	if (!(ka->sa.sa_flags & SA_NODEFER))
-		sigaddset(&current->blocked, sig);
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+		sigaddset(&blocked, sig);
+	sigprocmask(SIG_BLOCK, &blocked, NULL);
 
 	tracehook_signal_handler(sig, info, ka, regs,
 				 test_thread_flag(TIF_SINGLESTEP));

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