On Thu, 16 Nov 2023 at 08:57, Hangyu Hua <hbh25y@xxxxxxxxx> wrote:
>
> fuse_dax_conn_free() will be called when fuse_fill_super_common() fails
> after fuse_dax_conn_alloc(). Then deactivate_locked_super() in
> virtio_fs_get_tree() will call virtio_kill_sb() to release the discarded
> superblock. This will call fuse_dax_conn_free() again in fuse_conn_put(),
> resulting in a possible double free.
>
> Fixes: 1dd539577c42 ("virtiofs: add a mount option to enable dax")
> Signed-off-by: Hangyu Hua <hbh25y@xxxxxxxxx>
> ---
> fs/fuse/dax.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/fs/fuse/dax.c b/fs/fuse/dax.c
> index 23904a6a9a96..12ef91d170bb 100644
> --- a/fs/fuse/dax.c
> +++ b/fs/fuse/dax.c
> @@ -1222,6 +1222,7 @@ void fuse_dax_conn_free(struct fuse_conn *fc)
> if (fc->dax) {
> fuse_free_dax_mem_ranges(&fc->dax->free_ranges);
> kfree(fc->dax);
> + fc->dax = NULL;
Is there a reason not to simply remove the fuse_dax_conn_free() call
from the cleanup path in fuse_fill_super_common()?
Thanks,
Miklos
> }
> }
>
> --
> 2.34.1
>
