Re: [libvirt] [PATCH] uml_conf.c: don't return an uninitialized pointer

Daniel P. Berrange wrote: > On Thu, Sep 03, 2009 at 12:07:14PM +0200, Jim Meyering wrote: >> Another "real" bug: >> >> >From 6697607bf0b023ffb692576b31d652d10719b08a Mon Sep 17 00:00:00 2001 >> From: Jim Meyering <meyering(a)redhat.com&gt; >> Date: Thu, 3 Sep 2009 12:05:52 +0200 >> Subject: [PATCH] uml_conf.c: don't return an uninitialized pointer >> >> * src/uml_conf.c (umlBuildCommandLineChr): Initialize "ret" also >> in the final switch cases. >> --- >> src/uml_conf.c | 1 + >> 1 files changed, 1 insertions(+), 0 deletions(-) >> >> diff --git a/src/uml_conf.c b/src/uml_conf.c >> index 838fedd..2e9c25c 100644 >> --- a/src/uml_conf.c >> +++ b/src/uml_conf.c >> @@ -331,6 +331,7 @@ umlBuildCommandLineChr(virConnectPtr conn, >> default: >> umlReportError(conn, NULL, NULL, VIR_ERR_INTERNAL_ERROR, >> _("unsupported chr device type %d"), def->type); >> + ret = NULL; >> break; >> } > > I think this would be better changing the initial declartion to be > initializing to NULL too. Actually I did that first, but then un-did it in favor of the change above. Why? because that initialization could mask a failure to initialize in a new case. With per-case initialization, we'd detect the bug at compile/static-analysis time. With the up-front unconditional initialization, we cannot, and would have to rely on testing to find it.