在 2024/6/30 10:23, Sasha Levin 写道:

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 6.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: md-fix-overflow-in-is_mddev_idle.patch and it can be found in the queue-6.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

This patch is reverted by 504fbcffea649cad69111e7597081dd8adc3b395. It should not be added to the stable tree.

commit 4a45a13010724614f33c9096cee4a1ee19955aa0 Author: Li Nan linan122@huawei.com 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@huawei.com>
 Reviewed-by: Yu Kuai <yukuai3@huawei.com>
 Link: https://lore.kernel.org/r/20240117031946.2324519-2-linan666@huaweicloud.com
 Signed-off-by: Song Liu <song@kernel.org>
 Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/md/md.c b/drivers/md/md.c index e575e74aabf5e..c88b50a4be82f 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -8576,14 +8576,15 @@ 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 097d9dbd69b83..d0db98c0d33be 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -51,7 +51,7 @@ 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 @@ -621,7 +621,7 @@ 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 00e62b81a7363..a28cccd15f753 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -174,7 +174,7 @@ 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_ZONED .