From patchwork Thu Jun 11 18:10:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tom Zanussi X-Patchwork-Id: 213137 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5DCE6C433E0 for ; Thu, 11 Jun 2020 18:10:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3F87520792 for ; Thu, 11 Jun 2020 18:10:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591899039; bh=F5r+9LrUwOHW/0inDk1qiwGqErLuc8dWHLIh1RG7LiU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:In-Reply-To: References:List-ID:From; b=vknDLiTgodYH/cZtfMrH+tB8MmC9hbRvHalZ6JM0KB8OEXv0r0jJMKFN/zox8l9mg h9aFxm3H3dC8deuOTCH00RIt5e+ArB5WNLdwHtI/uMAEaVL5bAvOrErv6EYaCht22t KWF8EQwAy5nSpub8geWsSUBMx7f653dybwwd/2w0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725869AbgFKSKi (ORCPT ); Thu, 11 Jun 2020 14:10:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:38610 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726757AbgFKSKW (ORCPT ); Thu, 11 Jun 2020 14:10:22 -0400 Received: from localhost.localdomain (c-73-211-240-131.hsd1.il.comcast.net [73.211.240.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C078A20838; Thu, 11 Jun 2020 18:10:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591899021; bh=F5r+9LrUwOHW/0inDk1qiwGqErLuc8dWHLIh1RG7LiU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:In-Reply-To: References:From; b=pDRM/F/YdUtkQx3ZwbaKxxm1LqpvAy9ct66IyvpeHlBhpO6/KHVy1FaDxG3eyuYHd ZeouaKUljuEtB5AQFxB9BPR31KKumgQvImdVX5wxRUSoBULRLjXdZD2xTGmE53PchO 9uTdiPw3HVmkLm6QObelbd2zZfWbAjoEN4oK9F1U= From: zanussi@kernel.org To: LKML , linux-rt-users , Steven Rostedt , Thomas Gleixner , Carsten Emde , John Kacur , Sebastian Andrzej Siewior , Daniel Wagner , Clark Williams , Pavel Machek , Tom Zanussi Cc: Kevin Hao , stable-rt@vger.kernel.org Subject: [PATCH RT 2/4] mm: slub: Always flush the delayed empty slubs in flush_all() Date: Thu, 11 Jun 2020 13:10:15 -0500 Message-Id: <7f22ccf72a55f87d771a9dd0ea0c5e227b6b7b5c.1591898986.git.zanussi@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: References: In-Reply-To: References: Sender: linux-rt-users-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org From: Kevin Hao v4.19.127-rt55-rc1 stable review patch. If anyone has any objections, please let me know. ----------- [ Upstream commit 23a2c31b19e99beaf5107071b0f32a596202cdae ] After commit f0b231101c94 ("mm/SLUB: delay giving back empty slubs to IRQ enabled regions"), when the free_slab() is invoked with the IRQ disabled, the empty slubs are moved to a per-CPU list and will be freed after IRQ enabled later. But in the current codes, there is a check to see if there really has the cpu slub on a specific cpu before flushing the delayed empty slubs, this may cause a reference of already released kmem_cache in a scenario like below: cpu 0 cpu 1 kmem_cache_destroy() flush_all() --->IPI flush_cpu_slab() flush_slab() deactivate_slab() discard_slab() free_slab() c->page = NULL; for_each_online_cpu(cpu) if (!has_cpu_slab(1, s)) continue this skip to flush the delayed empty slub released by cpu1 kmem_cache_free(kmem_cache, s) kmalloc() __slab_alloc() free_delayed() __free_slab() reference to released kmem_cache Fixes: f0b231101c94 ("mm/SLUB: delay giving back empty slubs to IRQ enabled regions") Signed-off-by: Kevin Hao Signed-off-by: Sebastian Andrzej Siewior Cc: stable-rt@vger.kernel.org Signed-off-by: Tom Zanussi --- mm/slub.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index d243c6ef7fc9..a9473bbb1338 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2341,9 +2341,6 @@ static void flush_all(struct kmem_cache *s) for_each_online_cpu(cpu) { struct slub_free_list *f; - if (!has_cpu_slab(cpu, s)) - continue; - f = &per_cpu(slub_free_list, cpu); raw_spin_lock_irq(&f->lock); list_splice_init(&f->list, &tofree);