From 963696a41bce441ee4defdb846c6e735b15625c2 Mon Sep 17 00:00:00 2001
From: Roland McGrath <roland@redhat.com>
Date: Wed, 30 Jan 2008 13:30:06 +0100
Subject: [PATCH] --- yaml --- r: 79711 b: refs/heads/master c:
 83bd01024b1fdfc41d9b758e5669e80fca72df66 h: refs/heads/master i:   79709:
 e7ab36bd2ec2f7923c21d1cb0b00e39beff5e296   79707:
 a861994ed5d4576d4b428a90b3e39c56c42ae612   79703:
 93ff2e0e5ef50664caf1b46dfb62b8db66012ead   79695:
 1506c9b6eea8502355e84584887e29e2e5f70f9d   79679:
 8cb61a47267e80ef335bde3698d08d2c057fa17c v: v3

---
 [refs]                            | 2 +-
 trunk/arch/x86/kernel/signal_32.c | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 5707709ba845..ae242e4e0705 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: f9fc58910ebc448b0b7d37af1bf57a896a78e9c4
+refs/heads/master: 83bd01024b1fdfc41d9b758e5669e80fca72df66
diff --git a/trunk/arch/x86/kernel/signal_32.c b/trunk/arch/x86/kernel/signal_32.c
index 20f29e4c1d33..5c6170c44b00 100644
--- a/trunk/arch/x86/kernel/signal_32.c
+++ b/trunk/arch/x86/kernel/signal_32.c
@@ -295,6 +295,13 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
 	/* Default to using normal stack */
 	esp = regs->esp;
 
+	/*
+	 * If we are on the alternate signal stack and would overflow it, don't.
+	 * Return an always-bogus address instead so we will die with SIGSEGV.
+	 */
+	if (on_sig_stack(esp) && !likely(on_sig_stack(esp - frame_size)))
+		return (void __user *) -1L;
+
 	/* This is the X/Open sanctioned signal stack switching.  */
 	if (ka->sa.sa_flags & SA_ONSTACK) {
 		if (sas_ss_flags(esp) == 0)