This is a note to let you know that I've just added the patch titled
md: Fix overflow in is_mddev_idle
to the 6.1-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-fix-overflow-in-is_mddev_idle.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 6338df4eea90a285832af592547f2b04b667d019
Author: Li Nan <linan122@xxxxxxxxxx>
Date: Wed Jan 17 11:19:45 2024 +0800
md: Fix overflow in is_mddev_idle
[ Upstream commit 3f9f231236ce7e48780d8a4f1f8cb9fae2df1e4e ]
UBSAN reports this problem:
UBSAN: Undefined behaviour in drivers/md/md.c:8175:15
signed integer overflow:
-2147483291 - 2072033152 cannot be represented in type 'int'
Call trace:
dump_backtrace+0x0/0x310
show_stack+0x28/0x38
dump_stack+0xec/0x15c
ubsan_epilogue+0x18/0x84
handle_overflow+0x14c/0x19c
__ubsan_handle_sub_overflow+0x34/0x44
is_mddev_idle+0x338/0x3d8
md_do_sync+0x1bb8/0x1cf8
md_thread+0x220/0x288
kthread+0x1d8/0x1e0
ret_from_fork+0x10/0x18
'curr_events' will overflow when stat accum or 'sync_io' is greater than
INT_MAX.
Fix it by changing sync_io, last_events and curr_events to 64bit.
Signed-off-by: Li Nan <linan122@xxxxxxxxxx>
Reviewed-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240117031946.2324519-2-linan666@xxxxxxxxxxxxxxx
Signed-off-by: Song Liu <song@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 506c998c0ca59..3d2befb0baf46 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8542,14 +8542,15 @@ static int is_mddev_idle(struct mddev *mddev, int init)
{
struct md_rdev *rdev;
int idle;
- int curr_events;
+ long long curr_events;
idle = 1;
rcu_read_lock();
rdev_for_each_rcu(rdev, mddev) {
struct gendisk *disk = rdev->bdev->bd_disk;
- curr_events = (int)part_stat_read_accum(disk->part0, sectors) -
- atomic_read(&disk->sync_io);
+ curr_events =
+ (long long)part_stat_read_accum(disk->part0, sectors) -
+ atomic64_read(&disk->sync_io);
/* sync IO will cause sync_io to increase before the disk_stats
* as sync_io is counted when a request starts, and
* disk_stats is counted when it completes.
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 4f0b480974552..5910527514db2 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -50,7 +50,7 @@ struct md_rdev {
sector_t sectors; /* Device size (in 512bytes sectors) */
struct mddev *mddev; /* RAID array if running */
- int last_events; /* IO event timestamp */
+ long long last_events; /* IO event timestamp */
/*
* If meta_bdev is non-NULL, it means that a separate device is
@@ -576,7 +576,7 @@ extern void mddev_unlock(struct mddev *mddev);
static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
{
- atomic_add(nr_sectors, &bdev->bd_disk->sync_io);
+ atomic64_add(nr_sectors, &bdev->bd_disk->sync_io);
}
static inline void md_sync_acct_bio(struct bio *bio, unsigned long nr_sectors)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index e255674a9ee72..02e55676e0283 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -161,7 +161,7 @@ struct gendisk {
struct list_head slave_bdevs;
#endif
struct timer_rand_state *random;
- atomic_t sync_io; /* RAID */
+ atomic64_t sync_io; /* RAID */
struct disk_events *ev;
#ifdef CONFIG_BLK_DEV_INTEGRITY
struct kobject integrity_kobj;
