From e7dcf8339a0f3290944a301d22063d96c9aa4f70 Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Tue, 22 Aug 2023 20:50:59 +0300 Subject: [PATCH] ovl: fix incorrect fdput() on aio completion commit 724768a39374d35b70eaeae8dd87048a2ec7ae8e upstream. ovl_{read,write}_iter() always call fdput(real) to put one or zero refcounts of the real file, but for aio, whether it was submitted or not, ovl_aio_put() also calls fdput(), which is not balanced. This is only a problem in the less common case when FDPUT_FPUT flag is set. To fix the problem use get_file() to take file refcount and use fput() instead of fdput() in ovl_aio_put(). Fixes: 2406a307ac7d ("ovl: implement async IO routines") Cc: # v5.6 Reviewed-by: Miklos Szeredi Signed-off-by: Amir Goldstein Signed-off-by: Greg Kroah-Hartman --- fs/overlayfs/file.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index 6011f95..cc0c077 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -19,7 +19,6 @@ struct ovl_aio_req { struct kiocb iocb; refcount_t ref; struct kiocb *orig_iocb; - struct fd fd; }; static struct kmem_cache *ovl_aio_request_cachep; @@ -260,7 +259,7 @@ static rwf_t ovl_iocb_to_rwf(int ifl) static inline void ovl_aio_put(struct ovl_aio_req *aio_req) { if (refcount_dec_and_test(&aio_req->ref)) { - fdput(aio_req->fd); + fput(aio_req->iocb.ki_filp); kmem_cache_free(ovl_aio_request_cachep, aio_req); } } @@ -325,10 +324,9 @@ static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter) if (!aio_req) goto out; - aio_req->fd = real; real.flags = 0; aio_req->orig_iocb = iocb; - kiocb_clone(&aio_req->iocb, iocb, real.file); + kiocb_clone(&aio_req->iocb, iocb, get_file(real.file)); aio_req->iocb.ki_complete = ovl_aio_rw_complete; refcount_set(&aio_req->ref, 2); ret = vfs_iocb_iter_read(real.file, &aio_req->iocb, iter); @@ -396,10 +394,9 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter) /* Pacify lockdep, same trick as done in aio_write() */ __sb_writers_release(file_inode(real.file)->i_sb, SB_FREEZE_WRITE); - aio_req->fd = real; real.flags = 0; aio_req->orig_iocb = iocb; - kiocb_clone(&aio_req->iocb, iocb, real.file); + kiocb_clone(&aio_req->iocb, iocb, get_file(real.file)); aio_req->iocb.ki_flags = ifl; aio_req->iocb.ki_complete = ovl_aio_rw_complete; refcount_set(&aio_req->ref, 2); -- 2.7.4