From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bob Peterson Date: Wed, 14 Dec 2016 08:41:57 -0500 (EST) Subject: [Cluster-devel] [bug report] GFS2: Use resizable hash table for glocks In-Reply-To: <20161214085844.GA10659@elgon.mountain> References: <20161214085844.GA10659@elgon.mountain> Message-ID: <13637261.11653508.1481722917038.JavaMail.zimbra@redhat.com> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Hi Dan, ----- Original Message ----- | Hello Bob Peterson, | | The patch 88ffbf3e037e: "GFS2: Use resizable hash table for glocks" | from Mar 16, 2015, leads to the following static checker warning: | | fs/gfs2/glock.c:1813 gfs2_glock_iter_next() | error: 'gi->gl' dereferencing possible ERR_PTR() | | fs/gfs2/glock.c | 1803 static void gfs2_glock_iter_next(struct gfs2_glock_iter *gi) | 1804 { | 1805 do { | 1806 gi->gl = rhashtable_walk_next(&gi->hti); | 1807 if (IS_ERR(gi->gl)) { | 1808 if (PTR_ERR(gi->gl) == -EAGAIN) | 1809 continue; | | This continue was probably intended to go to the top of the loop, but | it's a do while loop so it actually drops down | | 1810 gi->gl = NULL; | 1811 } | 1812 /* Skip entries for other sb and dead entries */ | 1813 } while ((gi->gl) && ((gi->sdp != gi->gl->gl_name.ln_sbd) || | ^^^^^^^^ | to here where we dereference gi->gl. It's weird that Smatch is only | complaining about this now though... | | 1814 | __lockref_is_dead(&gi->gl->gl_lockref))); | 1815 } | | regards, | dan carpenter Yes, that looks like a bug. Do you have a patch or should I patch it? It is weird that it's never been flagged before. Thank goodness the circumstances that fail are unlikely: the table would have to be in the middle of a resize to return -EAGAIN, and I think that's only called when someone is dumping the glocks. Still, it's a bug, so we need to fix it. Regards, Bob Peterson Red Hat File Systems