On Tue, Dec 18, 2018 at 09:33:58AM -0800, Joe Perches wrote:
> On Tue, 2018-12-18 at 17:27 +0100, Nicholas Mc Guire wrote:
> > kzalloc can return NULL so a check is needed. While there is a
> > check for ret_buf there is no check for the allocation of
> > ret_buf->crfid.fid - this check is thus added. Both call-sites
> > of tconInfoAlloc() check for NULL return of tconInfoAlloc()
> > so returning NULL on failure of kzalloc() here seems appropriate.
> > As the kzalloc() is the only thing here that can fail it is
> > moved to the beginning so as not to initialize other resources
> > on failure of kzalloc.
> >
> > Signed-off-by: Nicholas Mc Guire <hofrat@xxxxxxxxx>
> > Fixes: 3d4ef9a15343 ("smb3: fix redundant opens on root")
> > ---
> >
> > Problem located with an experimental coccinelle script
> >
> > While at it make checkpatch happy by using *ret_buf->crfid.fid
> > rather than struct cifs_fid.
> >
> > Patch was compile tested with: x86_64_defconfig + CIFS=m
> > (with some unrelated smatch warnings and some pending cocci fixes)
> >
> > Patch is against v4.20-rc7 (localversion-next is next-20181218)
> []
> > diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
> []
> > @@ -113,6 +113,13 @@ tconInfoAlloc(void)
> > struct cifs_tcon *ret_buf;
> > ret_buf = kzalloc(sizeof(struct cifs_tcon), GFP_KERNEL);
> > if (ret_buf) {
> > + ret_buf->crfid.fid = kzalloc(sizeof(*ret_buf->crfid.fid),
> > + GFP_KERNEL);
> > + if (!ret_buf->crfid.fid) {
> > + kfree(ret_buf);
> > + return NULL;
> > + }
> > +
> > atomic_inc(&tconInfoAllocCount);
> > ret_buf->tidStatus = CifsNew;
> > ++ret_buf->tc_count;
> > @@ -120,8 +127,6 @@ tconInfoAlloc(void)
> > INIT_LIST_HEAD(&ret_buf->tcon_list);
> > spin_lock_init(&ret_buf->open_file_lock);
> > mutex_init(&ret_buf->crfid.fid_mutex);
> > - ret_buf->crfid.fid = kzalloc(sizeof(struct cifs_fid),
> > - GFP_KERNEL);
> > spin_lock_init(&ret_buf->stat_lock);
> > atomic_set(&ret_buf->num_local_opens, 0);
> > atomic_set(&ret_buf->num_remote_opens, 0);
>
> Perhaps use a more common style by returning early on the
> first possible failure too so the block can be unindented.
>
yup the restructured cleanup would be the better way to go
rather than making this two patches I guess it would be the
best to just skip the intermediate kzalloc only cleanup -
atleast I see little value in that intermediat step - so
could you take care of the kzalloc() in your refactoring
please ?
thx!
hofrat
> Maybe as a separate cleanup patch.
> ---
> fs/cifs/misc.c | 34 ++++++++++++++++++++--------------
> 1 file changed, 20 insertions(+), 14 deletions(-)
>
> diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
> index 113980dba4d8..bee203055b30 100644
> --- a/fs/cifs/misc.c
> +++ b/fs/cifs/misc.c
> @@ -111,21 +111,27 @@ struct cifs_tcon *
> tconInfoAlloc(void)
> {
> struct cifs_tcon *ret_buf;
> - ret_buf = kzalloc(sizeof(struct cifs_tcon), GFP_KERNEL);
> - if (ret_buf) {
> - atomic_inc(&tconInfoAllocCount);
> - ret_buf->tidStatus = CifsNew;
> - ++ret_buf->tc_count;
> - INIT_LIST_HEAD(&ret_buf->openFileList);
> - INIT_LIST_HEAD(&ret_buf->tcon_list);
> - spin_lock_init(&ret_buf->open_file_lock);
> - mutex_init(&ret_buf->crfid.fid_mutex);
> - ret_buf->crfid.fid = kzalloc(sizeof(struct cifs_fid),
> - GFP_KERNEL);
> - spin_lock_init(&ret_buf->stat_lock);
> - atomic_set(&ret_buf->num_local_opens, 0);
> - atomic_set(&ret_buf->num_remote_opens, 0);
> +
> + ret_buf = kzalloc(sizeof(*ret_buf), GFP_KERNEL);
> + if (!ret_buf)
> + return NULL;
> + ret_buf->crfid.fid = kzalloc(sizeof(*ret_buf->crfid.fid), GFP_KERNEL);
> + if (!ret_buf->crfid.fid) {
> + kfree(ret_buf);
> + return NULL;
> }
> +
> + atomic_inc(&tconInfoAllocCount);
> + ret_buf->tidStatus = CifsNew;
> + ++ret_buf->tc_count;
> + INIT_LIST_HEAD(&ret_buf->openFileList);
> + INIT_LIST_HEAD(&ret_buf->tcon_list);
> + spin_lock_init(&ret_buf->open_file_lock);
> + mutex_init(&ret_buf->crfid.fid_mutex);
> + spin_lock_init(&ret_buf->stat_lock);
> + atomic_set(&ret_buf->num_local_opens, 0);
> + atomic_set(&ret_buf->num_remote_opens, 0);
> +
> return ret_buf;
> }
>
>
