From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757036AbbICSp5 (ORCPT ); Thu, 3 Sep 2015 14:45:57 -0400 Received: from relay2.sgi.com ([192.48.180.65]:46050 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756494AbbICSpz (ORCPT ); Thu, 3 Sep 2015 14:45:55 -0400 Date: Thu, 3 Sep 2015 13:45:54 -0500 From: Dimitri Sivanich To: Sudip Mukherjee Cc: Arnd Bergmann , Greg Kroah-Hartman , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 4/5] drivers/misc/sgi-gru: fix dereference of ERR_PTR Message-ID: <20150903184554.GA4759@sgi.com> References: <1441291851-29411-1-git-send-email-sudipm.mukherjee@gmail.com> <1441291851-29411-4-git-send-email-sudipm.mukherjee@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1441291851-29411-4-git-send-email-sudipm.mukherjee@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 03, 2015 at 08:20:50PM +0530, Sudip Mukherjee wrote: > gru_alloc_gts() can fail and it can return ERR_PTR(errvalue). We should > not dereference it if it has returned error. And incase it has returned > error then wait for some time and try again. > > Signed-off-by: Sudip Mukherjee > --- > > v2: on error retry after msleep(1). > v1: returned error. > > drivers/misc/sgi-gru/grukservices.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/misc/sgi-gru/grukservices.c b/drivers/misc/sgi-gru/grukservices.c > index 490b79a..d64f2a0 100644 > --- a/drivers/misc/sgi-gru/grukservices.c > +++ b/drivers/misc/sgi-gru/grukservices.c > @@ -160,7 +160,14 @@ static void gru_load_kernel_context(struct gru_blade_state *bs, int blade_id) > down_write(&bs->bs_kgts_sema); > > if (!bs->bs_kgts) { > - bs->bs_kgts = gru_alloc_gts(NULL, 0, 0, 0, 0, 0); > + do { > + bs->bs_kgts = gru_alloc_gts(NULL, 0, 0, 0, 0, 0); > + if (IS_ERR(bs->bs_kgts)) { > + msleep(1); > + continue; > + } > + break; > + } while (true); How about this way (for a little more compactness)? + do { + bs->bs_kgts = gru_alloc_gts(NULL, 0, 0, 0, 0, 0); + if (!IS_ERR(bs->bs_kgts)) + break; + msleep(1) + } while (true); > bs->bs_kgts->ts_user_blade_id = blade_id; > } > kgts = bs->bs_kgts; > -- > 1.9.1