Commit cd16edba1c6a for kernel

commit cd16edba1c6a24af138e1a5ded2711231fffa99f
Author: Arnd Bergmann <arnd@arndb.de>
Date:   Thu Dec 4 11:19:10 2025 +0100

    ext4: fix ext4_tune_sb_params padding

    The padding at the end of struct ext4_tune_sb_params is architecture
    specific and in particular is different between x86-32 and x86-64,
    since the __u64 member only enforces struct alignment on the latter.

    This shows up as a new warning when test-building the headers with
    -Wpadded:

    include/linux/ext4.h:144:1: error: padding struct size to alignment boundary with 4 bytes [-Werror=padded]

    All members inside the structure are naturally aligned, so the only
    difference here is the amount of padding at the end. Make the padding
    explicit, to have a consistent sizeof(struct ext4_tune_sb_params) of
    232 on all architectures and avoid adding compat ioctl handling for
    EXT4_IOC_GET_TUNE_SB_PARAM/EXT4_IOC_SET_TUNE_SB_PARAM.

    This is an ABI break on x86-32 but hopefully this can go into 6.18.y early
    enough as a fixup so no actual users will be affected.  Alternatively, the
    kernel could handle the ioctl commands for both sizes (232 and 228 bytes)
    on all architectures.

    Fixes: 04a91570ac67 ("ext4: implemet new ioctls to set and get superblock parameters")
    Signed-off-by: Arnd Bergmann <arnd@arndb.de>
    Reviewed-by: Jan Kara <jack@suse.cz>
    Link: https://patch.msgid.link/20251204101914.1037148-1-arnd@kernel.org
    Signed-off-by: Theodore Ts'o <tytso@mit.edu>
    Cc: stable@kernel.org

diff --git a/include/uapi/linux/ext4.h b/include/uapi/linux/ext4.h
index 411dcc1e4a35..9c683991c32f 100644
--- a/include/uapi/linux/ext4.h
+++ b/include/uapi/linux/ext4.h
@@ -139,7 +139,7 @@ struct ext4_tune_sb_params {
 	__u32 clear_feature_incompat_mask;
 	__u32 clear_feature_ro_compat_mask;
 	__u8  mount_opts[64];
-	__u8  pad[64];
+	__u8  pad[68];
 };

 #define EXT4_TUNE_FL_ERRORS_BEHAVIOR	0x00000001