Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B354C433F5 for ; Fri, 10 Dec 2021 04:46:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236665AbhLJEtu (ORCPT ); Thu, 9 Dec 2021 23:49:50 -0500 Received: from szxga01-in.huawei.com ([45.249.212.187]:15717 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233120AbhLJEtq (ORCPT ); Thu, 9 Dec 2021 23:49:46 -0500 Received: from canpemm500008.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4J9JF12DkNzZfgs; Fri, 10 Dec 2021 12:43:17 +0800 (CST) Received: from localhost.huawei.com (10.175.124.27) by canpemm500008.china.huawei.com (7.192.105.151) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Fri, 10 Dec 2021 12:46:09 +0800 From: Li Jinlin To: , , , , , , , , , CC: , , , , Subject: [PATCH 2/3] drdb: Fix undefined behaviour in drbd_rs_c_min_rate_throttle Date: Fri, 10 Dec 2021 13:17:06 +0800 Message-ID: <20211210051707.2202646-3-lijinlin3@huawei.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211210051707.2202646-1-lijinlin3@huawei.com> References: <20211210051707.2202646-1-lijinlin3@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To canpemm500008.china.huawei.com (7.192.105.151) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When the stat aacum of the disk is greater than INT_MAX, its value becomes negative after casting to 'int', which may lead to overflow after subtracting a positive number. In the same way, when the value of rs_sect_ev is greater than INT_MAX, overflow may also occur. These situations will lead to undefined behavior. Otherwise, if the stat accum of the disk is close to INT_MAX when creating md, the initial value of rs_last_events would be set close to INT_MAX when mddev initializes IO event counters. 'curr_events - device->rs_last_events > 64' will always false during synchronization, which may cause resync is not throttled even if the lower device is busy. Fix by using atomic64_t type for rs_sect_ev, and using s64 type for curr_events/last_events. Signed-off-by: Li Jinlin --- drivers/block/drbd/drbd_bitmap.c | 2 +- drivers/block/drbd/drbd_int.h | 4 ++-- drivers/block/drbd/drbd_main.c | 2 +- drivers/block/drbd/drbd_receiver.c | 12 ++++++------ drivers/block/drbd/drbd_worker.c | 4 ++-- 5 files changed, 12 insertions(+), 12 deletions(-) diff --git a/drivers/block/drbd/drbd_bitmap.c b/drivers/block/drbd/drbd_bitmap.c index c1f816f896a8..d580f4071622 100644 --- a/drivers/block/drbd/drbd_bitmap.c +++ b/drivers/block/drbd/drbd_bitmap.c @@ -1021,7 +1021,7 @@ static void bm_page_io_async(struct drbd_bm_aio_ctx *ctx, int page_nr) __must_ho submit_bio(bio); /* this should not count as user activity and cause the * resync to throttle -- see drbd_rs_should_slow_down(). */ - atomic_add(len >> 9, &device->rs_sect_ev); + atomic64_add(len >> 9, &device->rs_sect_ev); } } diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h index f27d5b0f9a0b..1b71adc07e83 100644 --- a/drivers/block/drbd/drbd_int.h +++ b/drivers/block/drbd/drbd_int.h @@ -954,9 +954,9 @@ struct drbd_device { struct mutex *state_mutex; /* either own_state_mutex or first_peer_device(device)->connection->cstate_mutex */ char congestion_reason; /* Why we where congested... */ atomic_t rs_sect_in; /* for incoming resync data rate, SyncTarget */ - atomic_t rs_sect_ev; /* for submitted resync data rate, both */ + atomic64_t rs_sect_ev; /* for submitted resync data rate, both */ int rs_last_sect_ev; /* counter to compare with */ - int rs_last_events; /* counter of read or write "events" (unit sectors) + s64 rs_last_events; /* counter of read or write "events" (unit sectors) * on the lower level device when we last looked. */ int c_sync_rate; /* current resync rate after syncer throttle magic */ struct fifo_buffer *rs_plan_s; /* correction values of resync planer (RCU, connection->conn_update) */ diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c index 53ba2dddba6e..ea057bd60541 100644 --- a/drivers/block/drbd/drbd_main.c +++ b/drivers/block/drbd/drbd_main.c @@ -1974,7 +1974,7 @@ void drbd_init_set_defaults(struct drbd_device *device) atomic_set(&device->local_cnt, 0); atomic_set(&device->pp_in_use_by_net, 0); atomic_set(&device->rs_sect_in, 0); - atomic_set(&device->rs_sect_ev, 0); + atomic64_set(&device->rs_sect_ev, 0); atomic_set(&device->ap_in_flight, 0); atomic_set(&device->md_io.in_use, 0); diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c index 1f740e42e457..4b75ad3dd0cd 100644 --- a/drivers/block/drbd/drbd_receiver.c +++ b/drivers/block/drbd/drbd_receiver.c @@ -2106,7 +2106,7 @@ static int recv_resync_read(struct drbd_peer_device *peer_device, sector_t secto list_add_tail(&peer_req->w.list, &device->sync_ee); spin_unlock_irq(&device->resource->req_lock); - atomic_add(pi->size >> 9, &device->rs_sect_ev); + atomic64_add(pi->size >> 9, &device->rs_sect_ev); if (drbd_submit_peer_request(device, peer_req, REQ_OP_WRITE, 0, DRBD_FAULT_RS_WR) == 0) return 0; @@ -2792,7 +2792,7 @@ bool drbd_rs_c_min_rate_throttle(struct drbd_device *device) struct gendisk *disk = device->ldev->backing_bdev->bd_disk; unsigned long db, dt, dbdt; unsigned int c_min_rate; - int curr_events; + s64 curr_events; rcu_read_lock(); c_min_rate = rcu_dereference(device->ldev->disk_conf)->c_min_rate; @@ -2802,8 +2802,8 @@ bool drbd_rs_c_min_rate_throttle(struct drbd_device *device) if (c_min_rate == 0) return false; - curr_events = (int)part_stat_read_accum(disk->part0, sectors) - - atomic_read(&device->rs_sect_ev); + curr_events = (s64)part_stat_read_accum(disk->part0, sectors) - + atomic64_read(&device->rs_sect_ev); if (atomic_read(&device->ap_actlog_cnt) || curr_events - device->rs_last_events > 64) { @@ -3023,7 +3023,7 @@ static int receive_DataRequest(struct drbd_connection *connection, struct packet goto out_free_e; submit_for_resync: - atomic_add(size >> 9, &device->rs_sect_ev); + atomic64_add(size >> 9, &device->rs_sect_ev); submit: update_receiver_timing_details(connection, drbd_submit_peer_request); @@ -5019,7 +5019,7 @@ static int receive_rs_deallocated(struct drbd_connection *connection, struct pac list_add_tail(&peer_req->w.list, &device->sync_ee); spin_unlock_irq(&device->resource->req_lock); - atomic_add(pi->size >> 9, &device->rs_sect_ev); + atomic64_add(pi->size >> 9, &device->rs_sect_ev); err = drbd_submit_peer_request(device, peer_req, op, 0, DRBD_FAULT_RS_WR); if (err) { diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c index 64563bfdf0da..a4edd0a9c875 100644 --- a/drivers/block/drbd/drbd_worker.c +++ b/drivers/block/drbd/drbd_worker.c @@ -409,7 +409,7 @@ static int read_for_csum(struct drbd_peer_device *peer_device, sector_t sector, list_add_tail(&peer_req->w.list, &device->read_ee); spin_unlock_irq(&device->resource->req_lock); - atomic_add(size >> 9, &device->rs_sect_ev); + atomic64_add(size >> 9, &device->rs_sect_ev); if (drbd_submit_peer_request(device, peer_req, REQ_OP_READ, 0, DRBD_FAULT_RS_RD) == 0) return 0; @@ -1679,7 +1679,7 @@ void drbd_rs_controller_reset(struct drbd_device *device) struct fifo_buffer *plan; atomic_set(&device->rs_sect_in, 0); - atomic_set(&device->rs_sect_ev, 0); + atomic64_set(&device->rs_sect_ev, 0); device->rs_in_flight = 0; device->rs_last_events = (int)part_stat_read_accum(disk->part0, sectors); -- 2.27.0