From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [PATCH for-next V5 1/5] IB/uverbs: Fix reference counting usage of event files Date: Wed, 24 Jun 2015 11:57:38 -0600 Message-ID: <20150624175738.GC21033@obsidianresearch.com> References: <1434984438-21733-1-git-send-email-yishaih@mellanox.com> <1434984438-21733-2-git-send-email-yishaih@mellanox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1434984438-21733-2-git-send-email-yishaih-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Yishai Hadas Cc: dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, raindel-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org, jackm-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org List-Id: linux-rdma@vger.kernel.org On Mon, Jun 22, 2015 at 05:47:14PM +0300, Yishai Hadas wrote: > fd_install(resp.async_fd, filp); > @@ -386,6 +376,7 @@ ssize_t ib_uverbs_get_context(struct ib_uverbs_file *file, > return in_len; > > err_file: > + ib_uverbs_free_async_event_file(file); > fput(filp); This looks really weird. > +void ib_uverbs_free_async_event_file(struct ib_uverbs_file *file) > +{ > + kref_put(&file->async_file->ref, ib_uverbs_release_event_file); > + file->async_file = NULL; > +} So that put is supposed to pair with this get? > + uverbs_file->async_file = ev_file; > + kref_get(&uverbs_file->async_file->ref); [..] > + fput(filp); > + uverbs_file->async_file = NULL; But isn't it null? Again again, WTF? async_file is a kref'd thing, if you copy or assign to it you need to manipulate the kref, so the null assign should be dropping the ref. Whis looks good enough to remove ib_uverbs_free_async_event_file, if the flip is created OK then the uverbs_file->async file can remain set until the uverbs file is closed. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html