6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Amir Goldstein <amir73il@xxxxxxxxx>
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: <stable@xxxxxxxxxxxxxxx> # v5.6
Reviewed-by: Miklos Szeredi <miklos@xxxxxxxxxx>
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/overlayfs/file.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
--- 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;
@@ -277,7 +276,7 @@ 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);
}
}
@@ -342,10 +341,9 @@ static ssize_t ovl_read_iter(struct kioc
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);
@@ -413,10 +411,9 @@ static ssize_t ovl_write_iter(struct kio
/* 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);
