From: Alexandre Raymond <cerbere@gmail.com>
Date: Wed, 15 Jun 2011 05:20:31 +0000 (-0400)
Subject: Fix signal handling of SIG_IPI when io-thread is enabled
X-Git-Tag: v2.7.1~6575^2~35
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=89b9ba661bd2d6155308f895ec075d813f0e129b;p=mirror_qemu.git

Fix signal handling of SIG_IPI when io-thread is enabled

Both the signal thread (via sigwait()) and the cpu thread (via
a normal signal handler) were attempting to catch SIG_IPI.

This resulted in random freezes under Darwin.

This patch separates SIG_IPI from the rest of the signals handled
by the signal thread, because it is independently caught by the cpu
thread.

Signed-off-by: Alexandre Raymond <cerbere@gmail.com>
Acked-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
---

diff --git a/cpus.c b/cpus.c
index e02576cb66..3035314486 100644
--- a/cpus.c
+++ b/cpus.c
@@ -396,10 +396,18 @@ static int qemu_signal_init(void)
     sigaddset(&set, SIGUSR2);
     pthread_sigmask(SIG_UNBLOCK, &set, NULL);
 
+    /*
+     * SIG_IPI must be blocked in the main thread and must not be caught
+     * by sigwait() in the signal thread. Otherwise, the cpu thread will
+     * not catch it reliably.
+     */
+    sigemptyset(&set);
+    sigaddset(&set, SIG_IPI);
+    pthread_sigmask(SIG_BLOCK, &set, NULL);
+
     sigemptyset(&set);
     sigaddset(&set, SIGIO);
     sigaddset(&set, SIGALRM);
-    sigaddset(&set, SIG_IPI);
     sigaddset(&set, SIGBUS);
 #else
     sigemptyset(&set);