From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: [md PATCH 13/18] md/raid5: add rcu protection to rdev accesses in handle_failed_sync. Date: Thu, 02 Jun 2016 16:19:52 +1000 Message-ID: <20160602061952.2939.26791.stgit@noble> References: <20160602061319.2939.72280.stgit@noble> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160602061319.2939.72280.stgit@noble> Sender: linux-raid-owner@vger.kernel.org To: Shaohua Li Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids The rdev could be freed while handle_failed_sync is running, so rcu protection is needed. Signed-off-by: NeilBrown --- drivers/md/raid5.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 8959e6dd31dd..e9ad22d64bd7 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -3210,15 +3210,16 @@ handle_failed_sync(struct r5conf *conf, struct stripe_head *sh, /* During recovery devices cannot be removed, so * locking and refcounting of rdevs is not needed */ + rcu_read_lock(); for (i = 0; i < conf->raid_disks; i++) { - struct md_rdev *rdev = conf->disks[i].rdev; + struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev); if (rdev && !test_bit(Faulty, &rdev->flags) && !test_bit(In_sync, &rdev->flags) && !rdev_set_badblocks(rdev, sh->sector, STRIPE_SECTORS, 0)) abort = 1; - rdev = conf->disks[i].replacement; + rdev = rcu_dereference(conf->disks[i].replacement); if (rdev && !test_bit(Faulty, &rdev->flags) && !test_bit(In_sync, &rdev->flags) @@ -3226,6 +3227,7 @@ handle_failed_sync(struct r5conf *conf, struct stripe_head *sh, STRIPE_SECTORS, 0)) abort = 1; } + rcu_read_unlock(); if (abort) conf->recovery_disabled = conf->mddev->recovery_disabled;