[PATCH 6.12 013/112] exfat: check return value of sb_min_blocksize in exfat_read_boot_sector

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Yongpeng Yang <yangyongpeng@xiaomi.com>

commit f2c1f631630e01821fe4c3fdf6077bc7a8284f82 upstream.

sb_min_blocksize() may return 0. Check its return value to avoid
accessing the filesystem super block when sb->s_blocksize is 0.

Cc: stable@vger.kernel.org # v6.15
Fixes: 719c1e1829166d ("exfat: add super block operations")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Yongpeng Yang <yangyongpeng@xiaomi.com>
Link: https://patch.msgid.link/20251104125009.2111925-3-yangyongpeng.storage@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/exfat/super.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/fs/exfat/super.c
+++ b/fs/exfat/super.c
@@ -452,7 +452,10 @@ static int exfat_read_boot_sector(struct
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
 
 	/* set block size to read super block */
-	sb_min_blocksize(sb, 512);
+	if (!sb_min_blocksize(sb, 512)) {
+		exfat_err(sb, "unable to set blocksize");
+		return -EINVAL;
+	}
 
 	/* read boot sector */
 	sbi->boot_bh = sb_bread(sb, 0);