On Thu, 4 Apr 2013, kbuild test robot wrote:
> Date: Thu, 04 Apr 2013 12:28:29 +0800
> From: kbuild test robot <fengguang.wu@xxxxxxxxx>
> To: Lukas Czerner <lczerner@xxxxxxxxxx>
> Cc: Theodore Ts'o <tytso@xxxxxxx>, kbuild-all@xxxxxx
> Subject: [ext4:dev 16/18] fs/ext4/extents.c:3299:21: warning: 'abut_ex' may be
> used uninitialized in this function
>
> tree: git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git dev
> head: f78ee70db40040e6f38a5134527d4760254d6683
> commit: bc2d9db48c95ec6c9c5ecc97ddc61343d751f219 [16/18] ext4: Transfer initialized block to right neighbor if possible
> config: i386-randconfig-x005-0404 (attached as .config)
>
> Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
This one is false warning, because we only have allocated set if
abut_ex is initialized as well. But I wonder if it's worth to
silence the warning just by initializing abut_ex to NULL ?
Thanks!
-Lukas
>
> All warnings:
>
> fs/ext4/extents.c: In function 'ext4_ext_map_blocks':
> >> fs/ext4/extents.c:3299:21: warning: 'abut_ex' may be used uninitialized in this function [-Wmaybe-uninitialized]
> fs/ext4/extents.c:3156:27: note: 'abut_ex' was declared here
>
> vim +/abut_ex +3299 fs/ext4/extents.c
>
> 3283 ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
> 3284 ex->ee_len = cpu_to_le16(ee_len - map_len);
> 3285 ext4_ext_mark_uninitialized(ex); /* Restore the flag */
> 3286
> 3287 /* Extend abut_ex by 'map_len' blocks */
> 3288 abut_ex->ee_len = cpu_to_le16(next_len + map_len);
> 3289
> 3290 /* Result: number of initialized blocks past m_lblk */
> 3291 allocated = map_len;
> 3292 }
> 3293 }
> 3294 if (allocated) {
> 3295 /* Mark the block containing both extents as dirty */
> 3296 ext4_ext_dirty(handle, inode, path + depth);
> 3297
> 3298 /* Update path to point to the right extent */
> > 3299 path[depth].p_ext = abut_ex;
> 3300 goto out;
> 3301 } else
> 3302 allocated = ee_len - (map->m_lblk - ee_block);
> 3303
> 3304 WARN_ON(map->m_lblk < ee_block);
> 3305 /*
> 3306 * It is safe to convert extent to initialized via explicit
> 3307 * zeroout only if extent is fully insde i_size or new_size.
>
> ---
> 0-DAY kernel build testing backend Open Source Technology Center
> http://lists.01.org/mailman/listinfo/kbuild Intel Corporation
>
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
