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 B3DFEC433FE for ; Tue, 22 Nov 2022 03:29:32 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2EB208E0002; Mon, 21 Nov 2022 22:29:32 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 29B436B0078; Mon, 21 Nov 2022 22:29:32 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 18AAD8E0002; Mon, 21 Nov 2022 22:29:32 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 08A996B0075 for ; Mon, 21 Nov 2022 22:29:32 -0500 (EST) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id BC36C120555 for ; Tue, 22 Nov 2022 03:29:31 +0000 (UTC) X-FDA: 80159648142.12.231E787 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf09.hostedemail.com (Postfix) with ESMTP id 3543A140008 for ; Tue, 22 Nov 2022 03:29:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=SHjMjI7yfVJr+BdFxls4vQJ1s88rXEVK99tZWiVVzyU=; b=LS7Si/Qh65Jj/8JDwkiI0qHsWP NR6Ji2/Uy8g2HWEONTn7T3GZQ39YhNQvPggPJsYhh5pTXfpPWUosGylcitBUoBlaageIpSqZukay6 NCXrTGY8EuwPH8NK5+3N3lcbQbv7Sft5H0DPak3uqhXg7vrqKTvwqH5X/fLdGQ6XWloSCDyDBw+m3 Nuhpkzh7QEzxy6xquvEbExDVRs7aI0+ZQK5HE4CerQ1vWJVbHGLN0Y9MQe4J1tGZ837mhj99X8PPv ZiZn1F2kqTBUkkXSy+NHvRlGwqztSyjtbNnToXqFR7tv4S3br2nTe/16NoV8ZIRtb4k5SzdowGSzg Ma1czT5A==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1oxJyU-005tQS-In; Tue, 22 Nov 2022 03:29:30 +0000 Date: Tue, 22 Nov 2022 03:29:30 +0000 From: Matthew Wilcox To: Dan Carpenter Cc: a.badmaev@clicknet.pro, linux-mm@kvack.org Subject: Re: [bug report] mm: add zblock - new allocator for use via zpool API Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1669087771; a=rsa-sha256; cv=none; b=yrmK+18JMYeXl5MV1Zfv5sOzhQ2a0qTP196/NV2SqzpMfLCN0HbhNiuDILkoDNFlLy0BuV /P6Zu3bDlh/jz9+SC3zpzqRbLMbKbTRkmnHo9gj7lmVdtPli3Hp5wb1hJxEqVfIf6L7Mjs Z+7BPZIQdD6iYRRpkoIfDgeVUuPhBOs= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b="LS7Si/Qh"; dmarc=none; spf=none (imf09.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1669087771; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=SHjMjI7yfVJr+BdFxls4vQJ1s88rXEVK99tZWiVVzyU=; b=sPn8MrvZbMyAIE7QHoHB4KArurMeogmEgMVfIN80egX4iV5GLHWwOUunqZyPV/wdEBZ6Im zN3b1fmfY9WkGfnOuV+u+BCeIj7lACOs5jCTQK5YujbDjT/SwqdgW9ScPNOzSHDtJnxjlB PsyNu/V51JyTl/15StWN7xc/nuSQD/s= Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b="LS7Si/Qh"; dmarc=none; spf=none (imf09.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org X-Stat-Signature: ig4sehb6hx3347zza6em58ha7xemswci X-Rspamd-Queue-Id: 3543A140008 X-Rspam-User: X-Rspamd-Server: rspam11 X-HE-Tag: 1669087769-564091 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 Fri, Nov 18, 2022 at 03:20:32PM +0300, Dan Carpenter wrote: > Hello Ananda, > > The patch 9097e28c25c8: "mm: add zblock - new allocator for use via > zpool API" from Nov 4, 2022, leads to the following Smatch static > checker warning: > > mm/zblock.c:341 zblock_alloc() error: buffer overflow 'block_desc' 29 <= 29 (assuming for loop doesn't break) > mm/zblock.c:165 cache_insert_block() error: uninitialized symbol 'min_index'. > mm/zblock.c:412 zblock_reclaim_block() warn: always true condition '(block_type >= 0) => (0-u64max >= 0)' > > mm/zblock.c > 297 static int zblock_alloc(struct zblock_pool *pool, size_t size, gfp_t gfp, > 298 unsigned long *handle) > 299 { > 300 unsigned int block_type, slot; > 301 struct zblock_block *block; > 302 struct block_list *list; > 303 > 304 if (!size) > 305 return -EINVAL; > 306 > 307 if (size > PAGE_SIZE) > 308 return -ENOSPC; > 309 > 310 /* find basic block type with suitable slot size */ > 311 for (block_type = 0; block_type < ARRAY_SIZE(block_desc); block_type++) { > 312 if (size <= block_desc[block_type].slot_size) > 313 break; > 314 } > > "size" is always <= PAGE_SIZE. Is PAGE_SIZE always 4k? If so then this > code is fine. Smatch is bad at handling arrays. PAGE_SIZE is 8kB on SPARC/Alpha. It can be 64kB on PPC and ARM. It can even be 256kB on one of the weirdo architectures (but, honestly, it's OK if that breaks; it's not well-tested)..