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 E32FAC47DD9 for ; Wed, 28 Feb 2024 15:50:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5BE7C6B009E; Wed, 28 Feb 2024 10:50:09 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 56E926B00A0; Wed, 28 Feb 2024 10:50:09 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4364C6B00A1; Wed, 28 Feb 2024 10:50:09 -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 335126B009E for ; Wed, 28 Feb 2024 10:50:09 -0500 (EST) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 02262160FA3 for ; Wed, 28 Feb 2024 15:50:08 +0000 (UTC) X-FDA: 81841648938.18.4D1A641 Received: from out-173.mta1.migadu.com (out-173.mta1.migadu.com [95.215.58.173]) by imf21.hostedemail.com (Postfix) with ESMTP id 0B5EB1C0009 for ; Wed, 28 Feb 2024 15:50:06 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=Z6a2dbqw; spf=pass (imf21.hostedemail.com: domain of chengming.zhou@linux.dev designates 95.215.58.173 as permitted sender) smtp.mailfrom=chengming.zhou@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1709135407; 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-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=kTVSWQckrG1uhUwf4yE6louRKCzZfuwwkT2CYEv4alg=; b=vwi26iVocPPwz+vYm8DRlv/NkMnXm5ItA+CxHjaO73oAVa3DmVrf9QqWpfa9QDfJmpxp/n jizqMWhg4O0LcFvm3PZ5UcN7IedmCazZfXsz6+nvc0iFKAznpbemeNX/c79hmMYd47VRR7 fMKXVqaCN7XJIhMx13BH+nGHRZi99Fc= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1709135407; a=rsa-sha256; cv=none; b=yXvEyHAEfM8jnkjHFlz1FJx7cwTtnBw/8QP4pXSqOxVE3PhOSa9NQmykzdCaW9nr6DY8oN AL+1L8eMc3dS9IrMEUZSNfZZixZ4vA1ngreQWGdeezWrDLhhG0wKbcvQgZ4FIMBKctuOM9 tCGvWlvhLn6zVpdFYDCvEWXUtL9Agw8= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=Z6a2dbqw; spf=pass (imf21.hostedemail.com: domain of chengming.zhou@linux.dev designates 95.215.58.173 as permitted sender) smtp.mailfrom=chengming.zhou@linux.dev; dmarc=pass (policy=none) header.from=linux.dev X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1709135405; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=kTVSWQckrG1uhUwf4yE6louRKCzZfuwwkT2CYEv4alg=; b=Z6a2dbqwPm+KvT5A7tdVD+WC4yALKy9n7LbrvTyh9XpbDmn84qGxgCAiTe7mTvXHiMOdBg oIvs/mWxCVlXRJRwsAT3BJtv2L6nQDdTEoGPbz01rkkgKyPiMGbBUTEakx3wG+RbyUV51o xzEIlWuWUWspGgy0Z9yIIAxlL/F6G90= From: Chengming Zhou To: akpm@linux-foundation.org Cc: hannes@cmpxchg.org, yosryahmed@google.com, nphamcs@gmail.com, willy@infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Chengming Zhou Subject: [PATCH mm-unstable v2] mm/zswap: fix zswap_pools_lock usages after changing to percpu_ref Date: Wed, 28 Feb 2024 15:49:54 +0000 Message-Id: <20240228154954.3028626-1-chengming.zhou@linux.dev> In-Reply-To: <20240210-zswap-global-lru-v3-2-200495333595@bytedance.com> References: <20240210-zswap-global-lru-v3-2-200495333595@bytedance.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Stat-Signature: opscqwb4dp1h8fyuaywr97roj3n39m6y X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 0B5EB1C0009 X-Rspam-User: X-HE-Tag: 1709135406-419822 X-HE-Meta: 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 JSE9/ixU Vmphj2Nuh4AS6n3uC0X7UYha4FhbLLVAVwYNYx3BGq5yxRwAaEyMb5FgBHItmGUTcHHWaioE66IYNc1Me4BmFxFj9UO/0vPe02LHLbeDI+JhcSm9P9/zRSGzaRaCOY/s0QhTM 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: List-Subscribe: List-Unsubscribe: Now the release of zswap pool is controlled by percpu_ref, its release callback (__zswap_pool_empty()) will be called when percpu_ref hit 0. But this release callback may potentially be called from RCU callback context by percpu_ref_kill(), which maybe from the softirq context. So we need to use spin_lock/unlock_bh() to avoid potential deadlock. This problem is introduced by the commit f3da427e82c4 ("mm/zswap: change zswap_pool kref to percpu_ref"), which is in mm-unstable branch now. It can be reproduced by testing kernel build in tmpfs with zswap and CONFIG_LOCKDEP enabled, meanwhile changing the zswap compressor setting dynamically. Signed-off-by: Chengming Zhou --- v2: - Change to use spin_lock/unlock_bh(), per Matthew. --- mm/zswap.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/mm/zswap.c b/mm/zswap.c index 011e068eb355..da90933c6d20 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -459,7 +459,7 @@ static void __zswap_pool_empty(struct percpu_ref *ref) pool = container_of(ref, typeof(*pool), ref); - spin_lock(&zswap_pools_lock); + spin_lock_bh(&zswap_pools_lock); WARN_ON(pool == zswap_pool_current()); @@ -468,7 +468,7 @@ static void __zswap_pool_empty(struct percpu_ref *ref) INIT_WORK(&pool->release_work, __zswap_pool_release); schedule_work(&pool->release_work); - spin_unlock(&zswap_pools_lock); + spin_unlock_bh(&zswap_pools_lock); } static int __must_check zswap_pool_get(struct zswap_pool *pool) @@ -598,7 +598,7 @@ static int __zswap_param_set(const char *val, const struct kernel_param *kp, return -EINVAL; } - spin_lock(&zswap_pools_lock); + spin_lock_bh(&zswap_pools_lock); pool = zswap_pool_find_get(type, compressor); if (pool) { @@ -607,7 +607,7 @@ static int __zswap_param_set(const char *val, const struct kernel_param *kp, list_del_rcu(&pool->list); } - spin_unlock(&zswap_pools_lock); + spin_unlock_bh(&zswap_pools_lock); if (!pool) pool = zswap_pool_create(type, compressor); @@ -628,7 +628,7 @@ static int __zswap_param_set(const char *val, const struct kernel_param *kp, else ret = -EINVAL; - spin_lock(&zswap_pools_lock); + spin_lock_bh(&zswap_pools_lock); if (!ret) { put_pool = zswap_pool_current(); @@ -643,7 +643,7 @@ static int __zswap_param_set(const char *val, const struct kernel_param *kp, put_pool = pool; } - spin_unlock(&zswap_pools_lock); + spin_unlock_bh(&zswap_pools_lock); if (!zswap_has_pool && !pool) { /* if initial pool creation failed, and this pool creation also -- 2.40.1