From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A8F75C3DA7A for ; Tue, 20 Dec 2022 18:53:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230003AbiLTSxY (ORCPT ); Tue, 20 Dec 2022 13:53:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41648 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229724AbiLTSxV (ORCPT ); Tue, 20 Dec 2022 13:53:21 -0500 Received: from mail-wm1-x335.google.com (mail-wm1-x335.google.com [IPv6:2a00:1450:4864:20::335]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 821FB25E for ; Tue, 20 Dec 2022 10:53:20 -0800 (PST) Received: by mail-wm1-x335.google.com with SMTP id ay2-20020a05600c1e0200b003d22e3e796dso9596360wmb.0 for ; Tue, 20 Dec 2022 10:53:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=UzaumV1qmFEO+Q1QfIQVEyz9X6tRYoSPlnet4KT4SeU=; b=BwXrlbnI4MOJPppl3xaWkzqRn7rsVMlvfAbFJzqUV6pk1geozWThyH7nKND7+qD+CC AZhYZD/dRxcSx9OmHQ5WU6CLHG3qRdwqVaBhgWGznn98hJKAkYB9hhOkCg2tKUYHFdH5 PxzBw+Tjrz8KVv0E0R90Ttr2tqvXx+Zujlgo8v1OEYdvKPiXL7v01605dhdyuuTLVrR0 pFXpeY9AFf5EmCpP4VW/GU1ZpxcfnyOXnxspcAKD8+69RIbnaw9FviItL5mY0bGZ6l3V Fx8hkZrS4Wh9Xj9ntlbUIFL3ExPpPASpGZU8ngOC2w+VymcAp6nstjRZfoUXKDO2niNm Nyug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=UzaumV1qmFEO+Q1QfIQVEyz9X6tRYoSPlnet4KT4SeU=; b=Plj8WCO5E2kKBmIr9NrXDzedthj3Bgi/+K2A4lDgxUGzdI+owSu7gUHF4aQ74BG5IP Es6//02wObRrhJ9YiOnKMVITIWeEDRQIJG2PiscgrDx7YyknMFF53TQoiRYq6xMIlBYC UgVw5NEmw/E4NHfx54Nn4+9ny3Si4ePkrefcyX0IqhyrJeD3y5zW2iiDVXhKSRCbtchP I/MStRhSDHJGVPRrniJOYw644Nv/Pjt8APt8rda6efFF8Nx0hjK02ott8ifGAWGX7h4T BxTdhfpvadFa5yTygHbCXNF38f5QBvaiRRn+dnUrd9+l7e3VCUpz8Q8C+dHJfwqd+clt fo/w== X-Gm-Message-State: AFqh2kp8DqZYeLIop1TJEa+I8f8Yi9Da0JzwArNlYNVwGJM22m6yXARa 0As5V4h5T0Wcfx0ujw371PM= X-Google-Smtp-Source: AMrXdXsUNU2wbal/lIFQSPHp3gWmLxFK2JLY6OdIoUpfjNmrOJL1+CHBtos07cLIzoEOkkIT6SeKLQ== X-Received: by 2002:a05:600c:3b87:b0:3d2:813:138a with SMTP id n7-20020a05600c3b8700b003d20813138amr2512071wms.35.1671562399046; Tue, 20 Dec 2022 10:53:19 -0800 (PST) Received: from localhost ([2a00:23c5:dc8c:8701:1663:9a35:5a7b:1d76]) by smtp.gmail.com with ESMTPSA id iv14-20020a05600c548e00b003d35c09d4b9sm7338565wmb.40.2022.12.20.10.53.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 20 Dec 2022 10:53:18 -0800 (PST) Date: Tue, 20 Dec 2022 18:53:18 +0000 From: Lorenzo Stoakes To: "Uladzislau Rezki (Sony)" Cc: Andrew Morton , linux-mm@kvack.org, LKML , Baoquan He , Christoph Hellwig , Matthew Wilcox , Nicholas Piggin , Oleksiy Avramchenko Subject: Re: [PATCH 2/2] mm: vmalloc: Replace BUG_ON() by WARN_ON_ONCE() Message-ID: References: <20221220182704.181657-1-urezki@gmail.com> <20221220182704.181657-2-urezki@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221220182704.181657-2-urezki@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 20, 2022 at 07:27:04PM +0100, Uladzislau Rezki (Sony) wrote: > Currently a vm_unmap_ram() functions triggers a BUG() if an area > is not found. Replace it by the WARN_ON_ONCE() error message and > keep machine alive instead of stopping it. > > The worst case is a memory leaking. > > Signed-off-by: Uladzislau Rezki (Sony) > --- > mm/vmalloc.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 0fc38c36e0df..e05a0dc79ac5 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -2255,10 +2255,12 @@ void vm_unmap_ram(const void *mem, unsigned int count) > } > > va = find_unlink_vmap_area(addr); > - BUG_ON(!va); > - debug_check_no_locks_freed((void *)va->va_start, > - (va->va_end - va->va_start)); > - free_unmap_vmap_area(va); > + > + if (!WARN_ON_ONCE(!va)) { > + debug_check_no_locks_freed((void *)va->va_start, > + (va->va_end - va->va_start)); > + free_unmap_vmap_area(va); > + } > } > EXPORT_SYMBOL(vm_unmap_ram); > > -- > 2.30.2 > Absolutely in favour of this in principle (BUG_ON() is something we should resort to in only the direst of circumstances), one small nit - perhaps it'd be neater to simply make this a guard clause? E.g.:- if (!WARN_ON_ONCE(!va)) return; ...