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 24A23C433F5 for ; Tue, 31 May 2022 18:21:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344968AbiEaSVE (ORCPT ); Tue, 31 May 2022 14:21:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52090 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346991AbiEaSUy (ORCPT ); Tue, 31 May 2022 14:20:54 -0400 Received: from mail.cybernetics.com (mail.cybernetics.com [173.71.130.66]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CE2779C2DF for ; Tue, 31 May 2022 11:20:53 -0700 (PDT) X-ASG-Debug-ID: 1654021252-1cf43917f334b0a0001-xx1T2L Received: from cybernetics.com ([10.10.4.126]) by mail.cybernetics.com with ESMTP id ozEi06WftSCDC9Dn; Tue, 31 May 2022 14:20:52 -0400 (EDT) X-Barracuda-Envelope-From: tonyb@cybernetics.com X-ASG-Whitelist: Client DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=cybernetics.com; s=mail; bh=UMD3peLOU8xJDRQl6tZsqYH8OxWwTPFkkNKZO4VgqaY=; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:References:Cc:To:From: Content-Language:Subject:MIME-Version:Date:Message-ID; b=rydeBuE75zkiJLNnZRfb /WOveUINnngDKbuBAnssoipJio6AJ8XrL7lA7d2NMt/+12EgQmGf8wBBwWfKyMEadPRL7VtaKsi4T JRDTXjFqiek64nTQq0wNQegdcxjMhWIPs7A+BZAqIBPh7j1EN9i6chqiPkEMvl7Zyb2O2XsC+w= Received: from [10.157.2.224] (HELO [192.168.200.1]) by cybernetics.com (CommuniGate Pro SMTP 7.1.1) with ESMTPS id 11829220; Tue, 31 May 2022 14:20:52 -0400 Message-ID: Date: Tue, 31 May 2022 14:20:51 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: [PATCH 06/10] dmapool: ignore init_on_free when DMAPOOL_DEBUG enabled Content-Language: en-US X-ASG-Orig-Subj: [PATCH 06/10] dmapool: ignore init_on_free when DMAPOOL_DEBUG enabled From: Tony Battersby To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: iommu@lists.linux-foundation.org, kernel-team@fb.com, Matthew Wilcox , Keith Busch , Andy Shevchenko , Robin Murphy , Tony Lindgren References: <9b08ab7c-b80b-527d-9adf-7716b0868fbc@cybernetics.com> In-Reply-To: <9b08ab7c-b80b-527d-9adf-7716b0868fbc@cybernetics.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Barracuda-Connect: UNKNOWN[10.10.4.126] X-Barracuda-Start-Time: 1654021252 X-Barracuda-URL: https://10.10.4.122:443/cgi-mod/mark.cgi X-Barracuda-BRTS-Status: 1 X-Virus-Scanned: by bsmtpd at cybernetics.com X-Barracuda-Scan-Msg-Size: 1451 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There are two cases: 1) In the normal case that the memory is being freed correctly, then DMAPOOL_DEBUG will memset the memory anyway, so speed things up by avoiding a double-memset of the same memory. 2) In the abnormal case that DMAPOOL_DEBUG detects that a driver passes incorrect parameters to dma_pool_free() (e.g. double-free, invalid free, mismatched vaddr/dma, etc.), then that is a kernel bug, and we don't want to clear the passed-in possibly-invalid memory pointer because we can't be sure that the memory is really free. So don't clear it just because init_on_free=1. Signed-off-by: Tony Battersby --- mm/dmapool.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/mm/dmapool.c b/mm/dmapool.c index 7a9161d4f7a6..49019ef6dd83 100644 --- a/mm/dmapool.c +++ b/mm/dmapool.c @@ -415,8 +415,6 @@ void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) } offset = vaddr - page->vaddr; - if (want_init_on_free()) - memset(vaddr, 0, pool->size); #ifdef DMAPOOL_DEBUG if ((dma - page->dma) != offset) { spin_unlock_irqrestore(&pool->lock, flags); @@ -461,6 +459,9 @@ void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) goto freelist_corrupt; } memset(vaddr, POOL_POISON_FREED, pool->size); +#else + if (want_init_on_free()) + memset(vaddr, 0, pool->size); #endif page->in_use--; -- 2.25.1