* Re: Patch "md: Fix overflow in is_mddev_idle" has been added to the 6.9-stable tree
[not found] <20240630022346.2608108-1-sashal@kernel.org>
@ 2024-07-01 1:22 ` Li Nan
2024-07-02 8:40 ` Greg KH
0 siblings, 1 reply; 2+ messages in thread
From: Li Nan @ 2024-07-01 1:22 UTC (permalink / raw)
To: stable, stable-commits
Cc: Song Liu, Yu Kuai, Jens Axboe, yangerkun@huawei.com
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;a=summary
>
> The filename of the patch is:
> md-fix-overflow-in-is_mddev_idle.patch
> and it can be found in the queue-6.9 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
> .
--
Thanks,
Nan
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