[PATCH v2 7/9] ext4: set type of ac_groups_linear_remaining to __u32 to avoid overflow

Baokun Li
2024-02-27T09:10:12Z

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