From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx171.postini.com [74.125.245.171]) by kanga.kvack.org (Postfix) with SMTP id A6AE16B003C for ; Mon, 16 Sep 2013 12:16:43 -0400 (EDT) Received: by mail-ob0-f173.google.com with SMTP id vb8so4020028obc.4 for ; Mon, 16 Sep 2013 09:16:42 -0700 (PDT) Message-ID: <52372EEF.7050608@gmail.com> Date: Mon, 16 Sep 2013 12:16:47 -0400 From: KOSAKI Motohiro MIME-Version: 1.0 Subject: Re: [PATCH v2] mm/shmem.c: check the return value of mpol_to_str() References: <5215639D.1080202@asianux.com> <5227CF48.5080700@asianux.com> <522E6C14.7060006@asianux.com> <522EC3D1.4010806@asianux.com> <52312EC1.8080300@asianux.com> <523205A0.1000102@gmail.com> <5232773E.8090007@asianux.com> <5233424A.2050704@gmail.com> <5236732C.5060804@asianux.com> In-Reply-To: <5236732C.5060804@asianux.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Chen Gang Cc: KOSAKI Motohiro , David Rientjes , KOSAKI Motohiro , riel@redhat.com, hughd@google.com, xemul@parallels.com, Wanpeng Li , Cyrill Gorcunov , linux-mm@kvack.org, Andrew Morton (9/15/13 10:55 PM), Chen Gang wrote: > On 09/14/2013 12:50 AM, KOSAKI Motohiro wrote: >>> --- >>> mm/shmem.c | 2 +- >>> 1 files changed, 1 insertions(+), 1 deletions(-) >>> >>> diff --git a/mm/shmem.c b/mm/shmem.c >>> index 8612a95..3f81120 100644 >>> --- a/mm/shmem.c >>> +++ b/mm/shmem.c >>> @@ -890,7 +890,7 @@ static void shmem_show_mpol(struct seq_file *seq, >>> struct mempolicy *mpol) >>> if (!mpol || mpol->mode == MPOL_DEFAULT) >>> return; /* show nothing */ >>> >>> - mpol_to_str(buffer, sizeof(buffer), mpol); >>> + VM_BUG_ON(mpol_to_str(buffer, sizeof(buffer), mpol) < 0); >> >> NAK. VM_BUG_ON is a kind of assertion. It erase the contents if >> CONFIG_DEBUG_VM not set. >> An argument of assertion should not have any side effect. > > Oh, really it is. In my opinion, need use "BUG_ON(mpol_to_str() < 0)" > instead of "VM_BUG_ON(mpol_to_str() < 0);". BUG_ON() is safe. but I still don't like it. As far as I heard, Google changes BUG_ON as nop. So, BUG_ON(mpol_to_str() < 0) breaks google. Please treat an assertion as assertion. Not any other something. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org