When kobject_init_and_add() fails, btrfs_sysfs_add_space_info_type()
calls kobject_put(&space_info->kobj).

The kobject release callback space_info_release() frees space_info,
but the current error path in create_space_info() then calls
kfree(space_info) again, causing a double free.

Keep the direct kfree(space_info) for the earlier failure path, but
after btrfs_sysfs_add_space_info_type() has called kobject_put(), let
the kobject release callback handle the cleanup.

Fixes: a11224a016d6d ("btrfs: fix memory leaks in create_space_info() error paths")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
---
 fs/btrfs/space-info.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
index 3f08e450f796..d7176eb2fcbf 100644
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -311,7 +311,7 @@ static int create_space_info(struct btrfs_fs_info *info, u64 flags)
 
 	ret = btrfs_sysfs_add_space_info_type(space_info);
 	if (ret)
-		goto out_free;
+		return ret;
 
 	list_add(&space_info->list, &info->space_info);
 	if (flags & BTRFS_BLOCK_GROUP_DATA)
-- 
2.43.0

在 2026/4/1 13:43, Guangshuo Li 写道:
> When kobject_init_and_add() fails, btrfs_sysfs_add_space_info_type()
> calls kobject_put(&space_info->kobj).
> 
> The kobject release callback space_info_release() frees space_info,
> but the current error path in create_space_info() then calls
> kfree(space_info) again, causing a double free.

Can you give an example call chain of where such space_info_release() is 
triggered?

> 
> Keep the direct kfree(space_info) for the earlier failure path, but
> after btrfs_sysfs_add_space_info_type() has called kobject_put(), let
> the kobject release callback handle the cleanup.
> 
> Fixes: a11224a016d6d ("btrfs: fix memory leaks in create_space_info() error paths")
> Cc: stable@vger.kernel.org
> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
> ---
>   fs/btrfs/space-info.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
> index 3f08e450f796..d7176eb2fcbf 100644
> --- a/fs/btrfs/space-info.c
> +++ b/fs/btrfs/space-info.c
> @@ -311,7 +311,7 @@ static int create_space_info(struct btrfs_fs_info *info, u64 flags)
>   
>   	ret = btrfs_sysfs_add_space_info_type(space_info);
>   	if (ret)
> -		goto out_free;
> +		return ret;
>   
>   	list_add(&space_info->list, &info->space_info);
>   	if (flags & BTRFS_BLOCK_GROUP_DATA)