From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f182.google.com (mail-pf0-f182.google.com [209.85.192.182]) by kanga.kvack.org (Postfix) with ESMTP id B5AC76B0005 for ; Tue, 26 Jan 2016 18:14:13 -0500 (EST) Received: by mail-pf0-f182.google.com with SMTP id n128so106344975pfn.3 for ; Tue, 26 Jan 2016 15:14:13 -0800 (PST) Received: from mail-pa0-x22e.google.com (mail-pa0-x22e.google.com. [2607:f8b0:400e:c03::22e]) by mx.google.com with ESMTPS id fd9si4813543pad.134.2016.01.26.15.14.12 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 26 Jan 2016 15:14:13 -0800 (PST) Received: by mail-pa0-x22e.google.com with SMTP id ho8so104780097pac.2 for ; Tue, 26 Jan 2016 15:14:12 -0800 (PST) Date: Tue, 26 Jan 2016 15:14:11 -0800 (PST) From: David Rientjes Subject: Re: [PATCH v2 RESEND 1/2] arm, arm64: change_memory_common with numpages == 0 should be no-op. In-Reply-To: <20160126155919.GA28238@arm.com> Message-ID: References: <1453820393-31179-1-git-send-email-mika.penttila@nextfour.com> <1453820393-31179-2-git-send-email-mika.penttila@nextfour.com> <20160126155919.GA28238@arm.com> MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="397176738-193334197-1453850051=:25141" Sender: owner-linux-mm@kvack.org List-ID: To: Will Deacon Cc: mika.penttila@nextfour.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux@arm.linux.org.uk, catalin.marinas@arm.com This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --397176738-193334197-1453850051=:25141 Content-Type: TEXT/PLAIN; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT On Tue, 26 Jan 2016, Will Deacon wrote: > From 57adec866c0440976c96a4b8f5b59fb411b1cacb Mon Sep 17 00:00:00 2001 > From: =?UTF-8?q?Mika=20Penttil=C3=A4?= > Date: Tue, 26 Jan 2016 15:47:25 +0000 > Subject: [PATCH] arm64: mm: avoid calling apply_to_page_range on empty range > MIME-Version: 1.0 > Content-Type: text/plain; charset=UTF-8 > Content-Transfer-Encoding: 8bit > > Calling apply_to_page_range with an empty range results in a BUG_ON > from the core code. This can be triggered by trying to load the st_drv > module with CONFIG_DEBUG_SET_MODULE_RONX enabled: > > kernel BUG at mm/memory.c:1874! > Internal error: Oops - BUG: 0 [#1] PREEMPT SMP > Modules linked in: > CPU: 3 PID: 1764 Comm: insmod Not tainted 4.5.0-rc1+ #2 > Hardware name: ARM Juno development board (r0) (DT) > task: ffffffc9763b8000 ti: ffffffc975af8000 task.ti: ffffffc975af8000 > PC is at apply_to_page_range+0x2cc/0x2d0 > LR is at change_memory_common+0x80/0x108 > > This patch fixes the issue by making change_memory_common (called by the > set_memory_* functions) a NOP when numpages == 0, therefore avoiding the > erroneous call to apply_to_page_range and bringing us into line with x86 > and s390. > > Cc: > Reviewed-by: Laura Abbott > Acked-by: David Rientjes > Signed-off-by: Mika Penttila > Signed-off-by: Will Deacon > --- > arch/arm64/mm/pageattr.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c > index 3571c7309c5e..cf6240741134 100644 > --- a/arch/arm64/mm/pageattr.c > +++ b/arch/arm64/mm/pageattr.c > @@ -57,6 +57,9 @@ static int change_memory_common(unsigned long addr, int numpages, > if (end < MODULES_VADDR || end >= MODULES_END) > return -EINVAL; > > + if (!numpages) > + return 0; > + > data.set_mask = set_mask; > data.clear_mask = clear_mask; > LGTM, I think this issue goes back to 3.17 due to commit 11d91a770f1f ("arm64: Add CONFIG_DEBUG_SET_MODULE_RONX support") so perhaps annotate the stable@vger.kernel.org for 3.17+. --397176738-193334197-1453850051=:25141-- -- 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