From: Michael Brown <mcb30@ipxe.org>
Date: Fri, 13 Jun 2008 02:39:22 +0000 (+0100)
Subject: [process] Hold reference to process during call to step()
X-Git-Tag: v1.20.1~2645
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=068ef5f72d6acd7ebdd3ec4065c9e9aeb6ff9b1b;p=thirdparty%2Fipxe.git

[process] Hold reference to process during call to step()

It is conceivable that the process may terminate during the execution
of step().  If nothing else holds a reference to the containing
object, this would cause the object to be freed prior to returning
from step().

Add a ref_get()/ref_put() around the call to ->step() to prevent this
from happening.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
---

diff --git a/src/core/process.c b/src/core/process.c
index 940e3b878..d46737b04 100644
--- a/src/core/process.c
+++ b/src/core/process.c
@@ -82,9 +82,11 @@ void step ( void ) {
 	list_for_each_entry ( process, &run_queue, list ) {
 		list_del ( &process->list );
 		list_add_tail ( &process->list, &run_queue );
+		ref_get ( process->refcnt ); /* Inhibit destruction mid-step */
 		DBGC2 ( process, "PROCESS %p executing\n", process );
 		process->step ( process );
 		DBGC2 ( process, "PROCESS %p finished executing\n", process );
+		ref_put ( process->refcnt ); /* Allow destruction */
 		break;
 	}
 }