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From: Baokun Li <libaokun1@huawei.com>
To: <linux-ext4@vger.kernel.org>
CC: <tytso@mit.edu>, <adilger.kernel@dilger.ca>, <jack@suse.cz>,
	<ritesh.list@gmail.com>, <ojaswin@linux.ibm.com>, <adobriyan@gmail.com>,
	<linux-kernel@vger.kernel.org>, <yi.zhang@huawei.com>,
	<yangerkun@huawei.com>, <libaokun1@huawei.com>, <stable@kernel.org>
Subject: [PATCH v4 7/9] ext4: set type of ac_groups_linear_remaining to __u32 to avoid overflow
Date: Tue, 19 Mar 2024 19:33:23 +0800
Message-ID: <20240319113325.3110393-8-libaokun1@huawei.com>
In-Reply-To: <20240319113325.3110393-1-libaokun1@huawei.com>
References: <20240319113325.3110393-1-libaokun1@huawei.com>
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Now ac_groups_linear_remaining is of type __u16 and s_mb_max_linear_groups
is of type unsigned int, so an overflow occurs when setting a value above
65535 through the mb_max_linear_groups sysfs interface. Therefore, the
type of ac_groups_linear_remaining is set to __u32 to avoid overflow.

Fixes: 196e402adf2e ("ext4: improve cr 0 / cr 1 group scanning")
CC: stable@kernel.org
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/mballoc.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h
index 56938532b4ce..7bfc5fb5a128 100644
--- a/fs/ext4/mballoc.h
+++ b/fs/ext4/mballoc.h
@@ -193,8 +193,8 @@ struct ext4_allocation_context {
 	ext4_grpblk_t	ac_orig_goal_len;
 
 	__u32 ac_flags;		/* allocation hints */
+	__u32 ac_groups_linear_remaining;
 	__u16 ac_groups_scanned;
-	__u16 ac_groups_linear_remaining;
 	__u16 ac_found;
 	__u16 ac_cX_found[EXT4_MB_NUM_CRS];
 	__u16 ac_tail;
-- 
2.31.1