From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx132.postini.com [74.125.245.132]) by kanga.kvack.org (Postfix) with SMTP id 793926B0068 for ; Thu, 1 Nov 2012 19:20:34 -0400 (EDT) Date: Thu, 1 Nov 2012 19:20:30 -0400 From: Dave Jones Subject: Re: shmem_getpage_gfp VM_BUG_ON triggered. [3.7rc2] Message-ID: <20121101232030.GA25519@redhat.com> References: <20121025023738.GA27001@redhat.com> <20121101191052.GA5884@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Hugh Dickins Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org On Thu, Nov 01, 2012 at 04:03:40PM -0700, Hugh Dickins wrote: > > I just noticed we had a user report hitting this same warning, but > > with a different trace.. > > > > : [] warn_slowpath_common+0x7f/0xc0 > > : [] warn_slowpath_null+0x1a/0x20 > > : [] shmem_getpage_gfp+0x7f3/0x830 > > : [] ? vma_adjust+0x3ed/0x620 > > : [] shmem_file_aio_read+0x1f2/0x380 > > : [] do_sync_read+0xa7/0xe0 > > : [] vfs_read+0xa9/0x180 > > : [] sys_read+0x4a/0x90 > > : [] system_call_fastpath+0x16/0x1b > > Equally explicable by Hannes's hypothesis; > but useful supporting evidence, thank you. > > Except... earlier in the thread you explained how you hacked > #define VM_BUG_ON(cond) WARN_ON(cond) > to get this to come out as a warning instead of a bug, > and now it looks as if "a user" has here done the same. > > Which is very much a user's right, of course; but does > make me wonder whether that user might actually be davej ;) indirectly. I made the same change in the Fedora kernel a while ago to test a hypothesis that we weren't getting any VM_BUG_ON reports. Dave -- 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