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 X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 88515C10F13 for ; Tue, 16 Apr 2019 21:34:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 57F402075B for ; Tue, 16 Apr 2019 21:34:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="fkAT9tOh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730334AbfDPVeO (ORCPT ); Tue, 16 Apr 2019 17:34:14 -0400 Received: from mail-pf1-f195.google.com ([209.85.210.195]:40157 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726986AbfDPVeN (ORCPT ); Tue, 16 Apr 2019 17:34:13 -0400 Received: by mail-pf1-f195.google.com with SMTP id c207so11035834pfc.7; Tue, 16 Apr 2019 14:34:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Ei7MGJK3cNg6YsIfFndg/Tuj245aikkpJc46gnMQbH8=; b=fkAT9tOhau1IIWQqnoJdkumBhNVuxriP/eW70x9oFgP/S2l/dgpIMs8wsSx8YJgkqn xgwMKSpXmIbg1kj9234C9vYRig+HveoqQxmoPOGakJrFxtW3HBRh+hCCogfDcOin423H QjOIwXkPzm6RrDPctTDrZqqJWJDOrRLZ4oI80ijXEKvcsGjtFEW6Sv7z4cfHybOJ9ppl OnKXk8NrwIx/XVCKAESlcf4Kc91g6LXdjmChMGxvVHt0/pjduhsl/6wNyTQ9YE3whM7L 3R1tcVIn5XqiK6P/1e/mLy5QeRT3aGJuYBTJsJxF1SN6cv+Se5dq7+6b2DXanbhAfUts LJzg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Ei7MGJK3cNg6YsIfFndg/Tuj245aikkpJc46gnMQbH8=; b=rqtKuBH8s4kSRStEcZ6NjpHEH834UopeqZxEHo2FXHS4mMezSfQNrr/aVpoTGSvfSm kEJ1kmT4f4NdYxCQQg4E43xMRmLGHC56NIr+NlI9kwVBeN5WTKIkixWxmmsFw0b8gF9u 2jVmgsvXASh8hAXpNJgn10S0WX+tH5vICtR8GbmoR3UDvd5bi5WDbS4A7EE4IMPetzYt jK2sPB++U27+U1ES4q1CiESlWRq21+sLUFt9DY4A4ST6iXxk7A6mxBw1Oqa/BknhwBcF w4+2Tjgu/HaylGuISwPkQiJAnuElCAaPWzbJ59erTxalbOAJTS7Q6BDV1qQqkd6ReT0t NGNA== X-Gm-Message-State: APjAAAUZx1i2MQ6MNb5moiAALwxfxiT+QEeFrzESuUWqlPneGz6kMtEl ZNuuUE23iZMrnqhpp/+ySvwkWW6W X-Google-Smtp-Source: APXvYqzfW/tLmtlr6FiQvHfog3MSaS5juhjYkrjicRx23kTLdaHuyAv1HzRgauE4N6HZnpKD9V938Q== X-Received: by 2002:a62:1215:: with SMTP id a21mr84356141pfj.126.1555450452824; Tue, 16 Apr 2019 14:34:12 -0700 (PDT) Received: from tw-172-25-31-76.office.twttr.net ([8.25.197.24]) by smtp.gmail.com with ESMTPSA id y23sm74242127pfn.25.2019.04.16.14.34.10 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 16 Apr 2019 14:34:10 -0700 (PDT) From: Cong Wang To: linux-kernel@vger.kernel.org Cc: linux-edac@vger.kernel.org, Cong Wang , Tony Luck , Borislav Petkov , Thomas Gleixner Subject: [PATCH v2 2/2] ras: close the race condition with timer Date: Tue, 16 Apr 2019 14:33:51 -0700 Message-Id: <20190416213351.28999-2-xiyou.wangcong@gmail.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190416213351.28999-1-xiyou.wangcong@gmail.com> References: <20190416213351.28999-1-xiyou.wangcong@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-edac-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-edac@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Message-ID: <20190416213351.LZcRXRL1pq6_4KGfi9OUKpGRkx4JY9q2DDwikRSIve8@z> cec_timer_fn() is a timer callback which reads ce_arr.array[] and updates its decay values. Elements could be added to or removed from this global array in parallel, although the array itself will not grow or shrink. del_lru_elem_unlocked() uses FULL_COUNT() as a key to find a right element to remove, which could be affected by the parallel timer. Fix this by converting the timer to a delayed work as suggested by Borislav, to avoid using spinlock. Fixes: 011d82611172 ("RAS: Add a Corrected Errors Collector") Cc: Tony Luck Cc: Borislav Petkov Cc: Thomas Gleixner Signed-off-by: Cong Wang --- drivers/ras/cec.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/drivers/ras/cec.c b/drivers/ras/cec.c index a4ff54e50673..5c2040a7389d 100644 --- a/drivers/ras/cec.c +++ b/drivers/ras/cec.c @@ -2,6 +2,7 @@ #include #include #include +#include #include @@ -131,7 +132,7 @@ static unsigned int count_threshold = COUNT_MASK; #define CEC_TIMER_DEFAULT_INTERVAL 24 * 60 * 60 /* 24 hrs */ #define CEC_TIMER_MIN_INTERVAL 1 * 60 * 60 /* 1h */ #define CEC_TIMER_MAX_INTERVAL 30 * 24 * 60 * 60 /* one month */ -static struct timer_list cec_timer; +static struct delayed_work cec_work; static u64 timer_interval = CEC_TIMER_DEFAULT_INTERVAL; /* @@ -160,20 +161,21 @@ static void do_spring_cleaning(struct ce_array *ca) /* * @interval in seconds */ -static void cec_mod_timer(struct timer_list *t, unsigned long interval) +static void cec_mod_work(unsigned long interval) { unsigned long iv; - iv = interval * HZ + jiffies; - - mod_timer(t, round_jiffies(iv)); + iv = interval * HZ; + mod_delayed_work(system_wq, &cec_work, round_jiffies(iv)); } -static void cec_timer_fn(struct timer_list *unused) +static void cec_work_fn(struct work_struct *work) { + mutex_lock(&ce_mutex); do_spring_cleaning(&ce_arr); + mutex_unlock(&ce_mutex); - cec_mod_timer(&cec_timer, timer_interval); + cec_mod_work(timer_interval); } /* @@ -383,7 +385,7 @@ static int decay_interval_set(void *data, u64 val) timer_interval = val; - cec_mod_timer(&cec_timer, timer_interval); + cec_mod_work(timer_interval); return 0; } DEFINE_DEBUGFS_ATTRIBUTE(decay_interval_ops, u64_get, decay_interval_set, "%lld\n"); @@ -509,8 +511,8 @@ void __init cec_init(void) if (create_debugfs_nodes()) return; - timer_setup(&cec_timer, cec_timer_fn, 0); - cec_mod_timer(&cec_timer, CEC_TIMER_DEFAULT_INTERVAL); + INIT_DELAYED_WORK(&cec_work, cec_work_fn); + schedule_delayed_work(&cec_work, CEC_TIMER_DEFAULT_INTERVAL); pr_info("Correctable Errors collector initialized.\n"); } -- 2.20.1