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Message-ID: <20211210120631.2578505-3-lijinlin3@huawei.com>
Date: Fri, 10 Dec 2021 20:06:30 +0800
From: Li Jinlin <lijinlin3@...wei.com>
To: <song@...nel.org>, <philipp.reisner@...bit.com>,
<lars.ellenberg@...bit.com>, <axboe@...nel.dk>, <hare@...e.de>,
<jack@...e.cz>, <ming.lei@...hat.com>, <tj@...nel.org>,
<mcgrof@...nel.org>
CC: <linux-raid@...r.kernel.org>, <linux-block@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <linfeilong@...wei.com>
Subject: [PATCH v3 2/3] drbd: Fix undefined behaviour in drbd_rs_c_min_rate_throttle
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 value of rs_last_events would be set
close to INT_MAX. '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/rs_last_events.
Signed-off-by: Li Jinlin <lijinlin3@...wei.com>
---
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
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