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 DE237C433FE for ; Thu, 17 Nov 2022 13:37:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239628AbiKQNhd (ORCPT ); Thu, 17 Nov 2022 08:37:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50388 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240136AbiKQNhc (ORCPT ); Thu, 17 Nov 2022 08:37:32 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 052CF716E5 for ; Thu, 17 Nov 2022 05:36:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1668692195; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=nBqq6MkgH5sErymzvb4GgeAOGwNxrvye29zE4sqCkdM=; b=clARRpSdTTJrygFSsAu47wYM01iBTtGbrXDjEteW0S8tEMWes2Rw4PAZHQCw/Ea0ZYAZJe 5KqKo4wiruA6oFo88e2HO59aO1zSdYenvMsIqom9rkwBo205j0URSKcZzP6YdbnMNX3bC8 RXiSzSQVqPIPKOwbp4mknDgP1J5Yue8= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-12-bAaXkbKiNIyAjGr5fbbtQQ-1; Thu, 17 Nov 2022 08:36:31 -0500 X-MC-Unique: bAaXkbKiNIyAjGr5fbbtQQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 5BEDA101A52A; Thu, 17 Nov 2022 13:36:31 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.24]) by smtp.corp.redhat.com (Postfix) with ESMTP id 970342166B29; Thu, 17 Nov 2022 13:36:30 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20221117115023.1350181-2-dwysocha@redhat.com> References: <20221117115023.1350181-2-dwysocha@redhat.com> <20221117115023.1350181-1-dwysocha@redhat.com> To: Dave Wysochanski Cc: dhowells@redhat.com, Daire Byrne , Benjamin Maynard , linux-cachefs@redhat.com, linux-nfs@vger.kernel.org Subject: Re: [PATCH 1/1] fscache: Fix oops due to race with cookie_lru and use_cookie MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <3716090.1668692187.1@warthog.procyon.org.uk> Date: Thu, 17 Nov 2022 13:36:27 +0000 Message-ID: <3716091.1668692187@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org You can probably make this easier to trigger by putting a delay in the state machine if the flag is set: [fs/fscache/cookie.c] +#include ... static void fscache_cookie_state_machine(struct fscache_cookie *cookie) { enum fscache_cookie_state state; bool wake = false; _enter("c=%x", cookie->debug_id); again: + if (test_bit(FSCACHE_COOKIE_DO_LRU_DISCARD, &cookie->flags)) + msleep(100); again_locked: state = cookie->state; switch (state) { David