debugging sigpfe in qemu/rbd

gistfile1.txt

From eac2fbddb0f39f4780ac42e009ce60d56c78cb76 Mon Sep 17 00:00:00 2001
From: Josh Durgin <josh.durgin@inktank.com>
Date: Wed, 12 Sep 2012 17:39:57 -0700
Subject: [PATCH] print debug info for SIGPFE

---
 main-loop.c |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/main-loop.c b/main-loop.c
index eb3b6e6..c624172 100644
--- a/main-loop.c
+++ b/main-loop.c
@@ -130,10 +130,18 @@ static void sigfd_handler(void *opaque)
     }
 }
 
+static void debug_sigfpe(int signo, siginfo_t *info, void *opaque)
+{
+    printf("got SIGFPE! si_code = %d address = %p\n", info->si_code,
+           info->si_addr);
+    abort();
+}
+
 static int qemu_signal_init(void)
 {
     int sigfd;
     sigset_t set;
+    struct sigaction action;
 
     /*
      * SIG_IPI must be blocked in the main thread and must not be caught
@@ -147,7 +155,11 @@ static int qemu_signal_init(void)
     sigaddset(&set, SIGBUS);
     pthread_sigmask(SIG_BLOCK, &set, NULL);
 
+    action.sa_flags = SA_SIGINFO;
+    action.sa_sigaction = debug_sigfpe;
+    sigaction(SIGFPE, &action, NULL);
     sigdelset(&set, SIG_IPI);
+    sigaddset(&set, SIGFPE);
     sigfd = qemu_signalfd(&set);
     if (sigfd == -1) {
         fprintf(stderr, "failed to create signalfd\n");
-- 
1.7.2.5