From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:39954 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752715AbdGHInG (ORCPT ); Sat, 8 Jul 2017 04:43:06 -0400 Subject: Patch "gfs2: Fix glock rhashtable rcu bug" has been added to the 4.12-stable tree To: agruenba@redhat.com, gregkh@linuxfoundation.org, rpeterso@redhat.com Cc: , From: Date: Sat, 08 Jul 2017 10:43:03 +0200 Message-ID: <14995033831431@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled gfs2: Fix glock rhashtable rcu bug to the 4.12-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: gfs2-fix-glock-rhashtable-rcu-bug.patch and it can be found in the queue-4.12 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 961ae1d83d055a4b9ebbfb4cc8ca62ec1a7a3b74 Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Fri, 7 Jul 2017 13:22:05 -0500 Subject: gfs2: Fix glock rhashtable rcu bug From: Andreas Gruenbacher commit 961ae1d83d055a4b9ebbfb4cc8ca62ec1a7a3b74 upstream. Before commit 88ffbf3e03 "GFS2: Use resizable hash table for glocks", glocks were freed via call_rcu to allow reading the glock hashtable locklessly using rcu. This was then changed to free glocks immediately, which made reading the glock hashtable unsafe. Bring back the original code for freeing glocks via call_rcu. Signed-off-by: Andreas Gruenbacher Signed-off-by: Bob Peterson Signed-off-by: Greg Kroah-Hartman --- fs/gfs2/glock.c | 11 +++++++++-- fs/gfs2/incore.h | 1 + 2 files changed, 10 insertions(+), 2 deletions(-) --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -80,9 +80,9 @@ static struct rhashtable_params ht_parms static struct rhashtable gl_hash_table; -void gfs2_glock_free(struct gfs2_glock *gl) +static void gfs2_glock_dealloc(struct rcu_head *rcu) { - struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; + struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu); if (gl->gl_ops->go_flags & GLOF_ASPACE) { kmem_cache_free(gfs2_glock_aspace_cachep, gl); @@ -90,6 +90,13 @@ void gfs2_glock_free(struct gfs2_glock * kfree(gl->gl_lksb.sb_lvbptr); kmem_cache_free(gfs2_glock_cachep, gl); } +} + +void gfs2_glock_free(struct gfs2_glock *gl) +{ + struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; + + call_rcu(&gl->gl_rcu, gfs2_glock_dealloc); if (atomic_dec_and_test(&sdp->sd_glock_disposal)) wake_up(&sdp->sd_glock_wait); } --- a/fs/gfs2/incore.h +++ b/fs/gfs2/incore.h @@ -374,6 +374,7 @@ struct gfs2_glock { loff_t end; } gl_vm; }; + struct rcu_head gl_rcu; struct rhash_head gl_node; }; Patches currently in stable-queue which might be from agruenba@redhat.com are queue-4.12/gfs2-fix-glock-rhashtable-rcu-bug.patch