commit f259fcc00a04e633a7a64f894a719f78f3644867
Author: Willy Tarreau <w@1wt.eu>
Date:   Mon Aug 26 10:37:39 2019 +0200

    BUG/MINOR: mworker: disable SIGPROF on re-exec
    
    If haproxy is built with profiling enabled with -pg, it is possible to
    see the master quit during a reload while it's re-executing itself with
    error code 155 (signal 27) saying "Profile timer expired)". This happens
    if the SIGPROF signal is delivered during the execve() call while the
    handler was already unregistered. The issue itself is not directly inside
    haproxy but it's easy to address. This patch disables this signal before
    calling execvp() during a master reload. A simple test for this consists
    in running this little script with haproxy started in master-worker mode :
    
         $ while usleep 50000; do killall -USR2 haproxy; done
    
    This fix should be backported to all versions using the master-worker
    model.
    
    (cherry picked from commit e0d86e2c1caaaa2141118e3309d479de5f67e855)
    Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/src/haproxy.c b/src/haproxy.c
index f6f00fc1..c93b0d13 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -695,6 +695,7 @@ void mworker_reload()
 	}
 
 	ha_warning("Reexecuting Master process\n");
+	signal(SIGPROF, SIG_IGN);
 	execvp(next_argv[0], next_argv);
 
 	ha_warning("Failed to reexecute the master process [%d]: %s\n", pid, strerror(errno));