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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5A4F4C32772 for ; Tue, 23 Aug 2022 15:12:05 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 73B2A6B0073; Tue, 23 Aug 2022 11:12:04 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6E9796B0074; Tue, 23 Aug 2022 11:12:04 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5B1A28D0001; Tue, 23 Aug 2022 11:12:04 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 4B47F6B0073 for ; Tue, 23 Aug 2022 11:12:04 -0400 (EDT) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 2A36EC14B2 for ; Tue, 23 Aug 2022 15:12:04 +0000 (UTC) X-FDA: 79831197768.30.2CA3444 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by imf22.hostedemail.com (Postfix) with ESMTP id 281CFC001D for ; Tue, 23 Aug 2022 15:12:03 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id C13811F8C0; Tue, 23 Aug 2022 15:12:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1661267521; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=swl0ArwDJ9fYdGl9+sc2cIn33V7qnlspcwq64fzCXA4=; b=dZBF3VTSSiCBUwQ7srJtI4g56FuCHLt9c0BREgY+JUIqQpRGoPb4NZJpICbulz0m25lA0D 8BJM4N8BQlgIav4zdMz8kknukd3Y6BRtrks+J7AdxKzgMZsAxx6bokpALMXF6eA3znXHOw iYvUnwMo7RAogjslO/VZf6WjOPZEJxs= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1661267521; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=swl0ArwDJ9fYdGl9+sc2cIn33V7qnlspcwq64fzCXA4=; b=b14Y4p1UIoZYqGPFtWZ1sDYjp//mkgulkjKpJqcY92E0Izppe/Dx1wGK3VNFLg9cy4jgHT g4euHe2F1fAWC6AA== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 8AC9F13A89; Tue, 23 Aug 2022 15:12:01 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id iQqwIEHuBGMjFgAAMHmgww (envelope-from ); Tue, 23 Aug 2022 15:12:01 +0000 Message-ID: <66e25026-a86a-0157-3671-cf66eb53964c@suse.cz> Date: Tue, 23 Aug 2022 17:12:01 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.1.2 Subject: Re: [PATCH v4 17/17] mm/sl[au]b: check if large object is valid in __ksize() Content-Language: en-US To: Hyeonggon Yoo <42.hyeyoo@gmail.com>, Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Roman Gushchin Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Marco Elver References: <20220817101826.236819-1-42.hyeyoo@gmail.com> <20220817101826.236819-18-42.hyeyoo@gmail.com> From: Vlastimil Babka In-Reply-To: <20220817101826.236819-18-42.hyeyoo@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1661267523; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=swl0ArwDJ9fYdGl9+sc2cIn33V7qnlspcwq64fzCXA4=; b=8INBM0iqZm9vNywKhEC8SNmX3jW/WxHhvbY5GmWrl0h5cEWOKeTgB4gBO7w3sx5eKfr+bs x7ioMHd5pf556U0WjDkE3vprBCTs5jvax7Vl8kfY/Rop0oGQTzAZT6isUOl9yM0/PSCXkr 9XoW1uRiuR/U1jn8BEbXVTwNVWyNvm4= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=dZBF3VTS; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=b14Y4p1U; spf=pass (imf22.hostedemail.com: domain of vbabka@suse.cz designates 195.135.220.29 as permitted sender) smtp.mailfrom=vbabka@suse.cz; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1661267523; a=rsa-sha256; cv=none; b=NNugIEgLA7BGQizmcXcZ6PwyZ8ndOmnLixMs7glHCisT1NgEj/qXHlBZlMRcRDUQREFI98 Ftaq+ONiGUE53gijQnWolAgNbAqi13NVHtei3O68SsapbEgg5O5fYhYGH8KBJpjkEzmuPd 9z77rAPS9t2ZWsB4uNk75nzAXUF3Bas= X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 281CFC001D X-Rspam-User: Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=dZBF3VTS; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=b14Y4p1U; spf=pass (imf22.hostedemail.com: domain of vbabka@suse.cz designates 195.135.220.29 as permitted sender) smtp.mailfrom=vbabka@suse.cz; dmarc=none X-Stat-Signature: y1un5u66j84iznhfotwm56hs88q1jj6z X-HE-Tag: 1661267522-864355 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 8/17/22 12:18, Hyeonggon Yoo wrote: > If address of large object is not beginning of folio or size of > the folio is too small, it must be invalid. BUG() in such cases. > > Cc: Marco Elver > Suggested-by: Vlastimil Babka > Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> > Reviewed-by: Vlastimil Babka > --- > mm/slab_common.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/mm/slab_common.c b/mm/slab_common.c > index 9c273a5fb0d7..98d029212682 100644 > --- a/mm/slab_common.c > +++ b/mm/slab_common.c > @@ -984,8 +984,11 @@ size_t __ksize(const void *object) > > folio = virt_to_folio(object); > > - if (unlikely(!folio_test_slab(folio))) > + if (unlikely(!folio_test_slab(folio))) { > + BUG_ON(folio_size(folio) <= KMALLOC_MAX_CACHE_SIZE); > + BUG_ON(object != folio_address(folio)); > return folio_size(folio); > + } > > return slab_ksize(folio_slab(folio)->slab_cache); > } In light of latest Linus' rant on BUG_ON() [1] I'm changing it to WARN_ON and return 0, as it was in v3. [1] https://lore.kernel.org/all/CAHk-=wiEAH+ojSpAgx_Ep=NKPWHU8AdO3V56BXcCsU97oYJ1EA@mail.gmail.com/ diff --git a/mm/slab_common.c b/mm/slab_common.c index 98d029212682..a80c3a5e194d 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -985,8 +985,10 @@ size_t __ksize(const void *object) folio = virt_to_folio(object); if (unlikely(!folio_test_slab(folio))) { - BUG_ON(folio_size(folio) <= KMALLOC_MAX_CACHE_SIZE); - BUG_ON(object != folio_address(folio)); + if (WARN_ON(folio_size(folio) <= KMALLOC_MAX_CACHE_SIZE)) + return 0; + if (WARN_ON(object != folio_address(folio))) + return 0; return folio_size(folio); }