From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: Re: [PATCH resend] drivers: dma-buf: Change %p to %pK in debug messages Date: Wed, 6 Jun 2018 11:07:53 +0200 Message-ID: <20180606090753.GA27744@kroah.com> References: <20180605234041.246060-1-drosen@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20180605234041.246060-1-drosen@google.com> Sender: stable-owner@vger.kernel.org To: Daniel Rosenberg Cc: Sumit Semwal , linux-kernel@vger.kernel.org, Gustavo Padovan , linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, dri-devel@lists.freedesktop.org, kernel-team@android.com, Divya Ponnusamy , stable List-Id: dri-devel@lists.freedesktop.org On Tue, Jun 05, 2018 at 04:40:41PM -0700, Daniel Rosenberg wrote: > The format specifier %p can leak kernel addresses > while not valuing the kptr_restrict system settings. > Use %pK instead of %p, which also evaluates whether > kptr_restrict is set. > > Signed-off-by: Divya Ponnusamy > Signed-off-by: Daniel Rosenberg > Cc: stable > --- > drivers/dma-buf/sync_debug.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/dma-buf/sync_debug.c b/drivers/dma-buf/sync_debug.c > index c4c8ecb24aa9..d8d340542a79 100644 > --- a/drivers/dma-buf/sync_debug.c > +++ b/drivers/dma-buf/sync_debug.c > @@ -133,7 +133,7 @@ static void sync_print_sync_file(struct seq_file *s, > char buf[128]; > int i; > > - seq_printf(s, "[%p] %s: %s\n", sync_file, > + seq_printf(s, "[%pK] %s: %s\n", sync_file, This is a root-only file, right? So it's not that bad of a problem. Also, by default, all %p pointers are now hashed so what really is leaking here? And finally, why even print out a pointer at all? Why not just stick with the name and not worry about the pointer? thanks, greg k-h