Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752889Ab3F0Jjw (ORCPT ); Thu, 27 Jun 2013 05:39:52 -0400 Received: from eddie.linux-mips.org ([78.24.191.182]:56874 "EHLO cvs.linux-mips.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751003Ab3F0Jjv (ORCPT ); Thu, 27 Jun 2013 05:39:51 -0400 Date: Thu, 27 Jun 2013 11:39:17 +0200 From: Ralf Baechle To: Veli-Pekka Peltola Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@linux-mips.org, Russell King , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Peter Zijlstra , Rusty Russell , Andrew Morton Subject: Re: [PATCH v2] mm: module_alloc: check if size is 0 Message-ID: <20130627093917.GQ7171@linux-mips.org> References: <1330631119-10059-1-git-send-email-veli-pekka.peltola@bluegiga.com> <1331125768-25454-1-git-send-email-veli-pekka.peltola@bluegiga.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1331125768-25454-1-git-send-email-veli-pekka.peltola@bluegiga.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 Content-Length: 2798 Lines: 78 Warming up an ancient thread because the discussion seems to have just stalled at some point and I still have this patch bitrotting in patchwork. The original thread can be found at: http://www.linux-mips.org/archives/linux-mips/2012-03/msg00006.html http://www.linux-mips.org/archives/linux-mips/2012-03/msg00028.html On Wed, Mar 07, 2012 at 03:09:28PM +0200, Veli-Pekka Peltola wrote: > After commit de7d2b567d040e3b67fe7121945982f14343213d (mm/vmalloc.c: report > more vmalloc failures) users will get a warning if vmalloc_node_range() is > called with size 0. This happens if module's init size equals to 0. This > patch changes ARM, MIPS and x86 module_alloc() to return NULL before calling > vmalloc_node_range() that would also return NULL and print a warning. > > Signed-off-by: Veli-Pekka Peltola > Cc: Russell King > Cc: Thomas Gleixner > Cc: Ingo Molnar > Cc: "H. Peter Anvin" > Cc: x86@kernel.org > --- > I found this with ARM but after checking out various implementations of > module_alloc() I thought it would be better to fix all at once. > > One way to replicate the warning: > compile kernel with CONFIG_KALLSYMS=n > insmod a module without init, I used usb-common.ko I didn't try to reproduce the issue but the code in question doesn't seem to have changed so the issue should still persist. Imho de7d2b567d040e3b67fe7121945982f14343213d [mm/vmalloc.c: report more vmalloc failures] is overly strict in that it also reports zero-sized allocations. I consider such allocations stupid but legitimiate and often better preferrable over having to scatter checks for zero size all over place. So maybe something like below patch? Thanks, Ralf --- Signed-off-by: Ralf Baechle mm/vmalloc.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index d365724..e58ca10 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1679,7 +1679,10 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, unsigned long real_size = size; size = PAGE_ALIGN(size); - if (!size || (size >> PAGE_SHIFT) > totalram_pages) + if (unlikely(!size)) + return NULL; + + if ((size >> PAGE_SHIFT) > totalram_pages) goto fail; area = __get_vm_area_node(size, align, VM_ALLOC | VM_UNLIST, @@ -1711,6 +1714,7 @@ fail: warn_alloc_failed(gfp_mask, 0, "vmalloc: allocation failure: %lu bytes\n", real_size); + return NULL; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/