From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3v3hyZ3jtJzDqGr for ; Thu, 19 Jan 2017 09:50:46 +1100 (AEDT) Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v0IMiDp4086063 for ; Wed, 18 Jan 2017 17:50:44 -0500 Received: from e23smtp01.au.ibm.com (e23smtp01.au.ibm.com [202.81.31.143]) by mx0a-001b2d01.pphosted.com with ESMTP id 282br7pgw9-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 18 Jan 2017 17:50:43 -0500 Received: from localhost by e23smtp01.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 19 Jan 2017 08:50:41 +1000 Received: from d23relay07.au.ibm.com (d23relay07.au.ibm.com [9.190.26.37]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id 177D22BB0045 for ; Thu, 19 Jan 2017 09:50:39 +1100 (EST) Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by d23relay07.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v0IModBu19136570 for ; Thu, 19 Jan 2017 09:50:39 +1100 Received: from d23av04.au.ibm.com (localhost [127.0.0.1]) by d23av04.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id v0IMocnf015562 for ; Thu, 19 Jan 2017 09:50:38 +1100 Date: Thu, 19 Jan 2017 09:50:38 +1100 From: Gavin Shan To: Michael Ellerman Cc: Gavin Shan , linuxppc-dev@lists.ozlabs.org, ruscur@russell.cc Subject: Re: [PATCH] powerpc/eeh: Fix wrong flag passed to eeh_unfreeze_pe() Reply-To: Gavin Shan References: <1484104609-22129-1-git-send-email-gwshan@linux.vnet.ibm.com> <87wpdsapdl.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <87wpdsapdl.fsf@concordia.ellerman.id.au> Message-Id: <20170118225038.GA5397@gwshan> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, Jan 18, 2017 at 04:49:58PM +1100, Michael Ellerman wrote: >Gavin Shan writes: > >> In __eeh_clear_pe_frozen_state(), we should pass the flag's value >> instead of its address to eeh_unfreeze_pe(). This doesn't introduce >> any problems, but the code is just wrong. > >It means any caller that passes false, will be getting the wrong >behaviour. eg. I see at least one call in eeh_reset_device() which >passes false to eeh_clear_pe_frozen_state(), which is then passed to >__eeh_clear_pe_frozen_state(). > Yes, when __eeh_clear_pe_frozen_state() succeeds on all child PEs, the isolated flag is cleared. No failure from __eeh_clear_pe_frozen_state() was observed previously. >But I guess you're saying that caller doesn't actually see a bug because >of this? > Yes, I'll update the changelog accordingly, to give more details as above. >> This fixes the code by passing flag's value to eeh_unfreeze_pe(). >> >> Cc: stable@vger.kernel.org #3.18+ >> Fixes: 5cfb20b96f6 ("powerpc/eeh: Emulate EEH recovery for VFIO devices") >> Signed-off-by: Gavin Shan >> >> diff --git a/arch/powerpc/kernel/eeh_driver.c b/arch/powerpc/kernel/eeh_driver.c >> index d88573b..fa15fa6 100644 >> --- a/arch/powerpc/kernel/eeh_driver.c >> +++ b/arch/powerpc/kernel/eeh_driver.c >> @@ -549,7 +549,7 @@ static void *__eeh_clear_pe_frozen_state(void *data, void *flag) > > bool *clear_sw_state = flag; > >> int i, rc = 1; >> >> for (i = 0; rc && i < 3; i++) >> - rc = eeh_unfreeze_pe(pe, clear_sw_state); >> + rc = eeh_unfreeze_pe(pe, *clear_sw_state); > > >I think it would be better to just do the dereference once: > > bool clear_sw_state = *(bool *)flag; > int i, rc = 1; > > for (i = 0; rc && i < 3; i++) > rc = eeh_unfreeze_pe(pe, clear_sw_state); > Thanks, Michael. I'll update in v2. Thanks, Gavin