From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:52566 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753217AbbIZR0h (ORCPT ); Sat, 26 Sep 2015 13:26:37 -0400 Subject: Patch "md/raid5: don't let shrink_slab shrink too far." has been added to the 4.1-stable tree To: neilb@suse.com, gregkh@linuxfoundation.org, tomas.papan@gmail.com Cc: , From: Date: Sat, 26 Sep 2015 10:26:35 -0700 Message-ID: <1443288395149250@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 md/raid5: don't let shrink_slab shrink too far. to the 4.1-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: md-raid5-don-t-let-shrink_slab-shrink-too-far.patch and it can be found in the queue-4.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 49895bcc7e566ba455eb2996607d6fbd3447ce16 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Mon, 3 Aug 2015 17:09:57 +1000 Subject: md/raid5: don't let shrink_slab shrink too far. From: NeilBrown commit 49895bcc7e566ba455eb2996607d6fbd3447ce16 upstream. I have a report of drop_one_stripe() called from raid5_cache_scan() apparently finding ->max_nr_stripes == 0. This should not be allowed. So add a test to keep max_nr_stripes above min_nr_stripes. Also use a 'mask' rather than a 'mod' in drop_one_stripe to ensure 'hash' is valid even if max_nr_stripes does reach zero. Fixes: edbe83ab4c27 ("md/raid5: allow the stripe_cache to grow and shrink.") Reported-by: Tomas Papan Signed-off-by: NeilBrown Signed-off-by: Greg Kroah-Hartman --- drivers/md/raid5.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -2245,7 +2245,7 @@ static int resize_stripes(struct r5conf static int drop_one_stripe(struct r5conf *conf) { struct stripe_head *sh; - int hash = (conf->max_nr_stripes - 1) % NR_STRIPE_HASH_LOCKS; + int hash = (conf->max_nr_stripes - 1) & STRIPE_HASH_LOCKS_MASK; spin_lock_irq(conf->hash_locks + hash); sh = get_free_stripe(conf, hash); @@ -6375,7 +6375,8 @@ static unsigned long raid5_cache_scan(st if (mutex_trylock(&conf->cache_size_mutex)) { ret= 0; - while (ret < sc->nr_to_scan) { + while (ret < sc->nr_to_scan && + conf->max_nr_stripes > conf->min_nr_stripes) { if (drop_one_stripe(conf) == 0) { ret = SHRINK_STOP; break; Patches currently in stable-queue which might be from neilb@suse.com are queue-4.1/md-raid5-avoid-races-when-changing-cache-size.patch queue-4.1/md-flush-event_work-before-stopping-array.patch queue-4.1/md-raid5-don-t-let-shrink_slab-shrink-too-far.patch queue-4.1/nfsv4-don-t-set-setattr-for-o_rdonly-o_excl.patch queue-4.1/md-raid10-always-set-reshape_safe-when-initializing-reshape_position.patch