Re: Patch "md: Fix overflow in is_mddev_idle" has been added to the 6.9-stable tree

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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@xxxxxxxxxxxxxxx> know about it.



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


commit 4a45a13010724614f33c9096cee4a1ee19955aa0
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 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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