On 30/11/2023 18:54, Miklos Szeredi wrote:
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()?
I think setting fc->dax to NULL keeps the memory allocation and release functions together in fuse_fill_super_common more readable. What do you think?
Thanks, Hangyu
Thanks, Miklos} } -- 2.34.1
