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=-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,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 2A7F2C33CB1 for ; Thu, 16 Jan 2020 14:45:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F1EA9207E0 for ; Thu, 16 Jan 2020 14:45:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579185929; bh=v9XSHMwY4zRV2HP2e0bNBZ2kNH3h9xSoS9wOX3LfJyY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=s4Mklhvl2wOJe2uZFlk5gZFkezfInghvs5CJz0LDdZuSMG1VYkKys/NVgeOj0B9ui qZjMiqv6ijZqDFgva718wv0rEU8rVieLObYfw71dBrzfs6r3FSJojgsFZyjczocnvf WEINS+ke/Pcq8M0ZkvuKt3mi8H8V+KiIudjYKuHU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726653AbgAPOp2 (ORCPT ); Thu, 16 Jan 2020 09:45:28 -0500 Received: from mail.kernel.org ([198.145.29.99]:35926 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726151AbgAPOp2 (ORCPT ); Thu, 16 Jan 2020 09:45:28 -0500 Received: from localhost.localdomain (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (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 7CDA620684; Thu, 16 Jan 2020 14:45:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579185928; bh=v9XSHMwY4zRV2HP2e0bNBZ2kNH3h9xSoS9wOX3LfJyY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lZmsfnjl/45yfEKSdW3gYOarkWTgBYTp1NCFZ0ZWJoxamfHp/pY0DZqEnA1pce2Pu oiiTZ1xkqZ8GaZ4b50ORoHpdXhWGOeDXprvArZuIJdebKMHF/QZN7HcSvo/75qeVLq wvEXzznDuHFyvOB8nuZCFV+KPdNA9jKDV/K+UfGY= From: Masami Hiramatsu To: Brendan Gregg , Steven Rostedt , Alexei Starovoitov Cc: mhiramat@kernel.org, Ingo Molnar , bpf@vger.kernel.org, linux-kernel@vger.kernel.org, Daniel Borkmann , Arnaldo Carvalho de Melo , "David S . Miller" , paulmck@kernel.org, joel@joelfernandes.org, "Naveen N . Rao" , Anil S Keshavamurthy Subject: [RFT PATCH 07/13] kprobes: Use normal list traversal API if a mutex is held Date: Thu, 16 Jan 2020 23:45:23 +0900 Message-Id: <157918592332.29301.1564446199611592837.stgit@devnote2> X-Mailer: git-send-email 2.20.1 In-Reply-To: <157918584866.29301.6941815715391411338.stgit@devnote2> References: <157918584866.29301.6941815715391411338.stgit@devnote2> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Use normal list traversal API instead of rcu_read_lock, RCU list traversal and rcu_read_unlock pair if a mutex which protects the list is held in the methods of kprobe_insn_cache. Signed-off-by: Masami Hiramatsu --- kernel/kprobes.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 848c14e92ccc..09b0e33bc845 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -141,8 +141,7 @@ kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c) /* Since the slot array is not protected by rcu, we need a mutex */ mutex_lock(&c->mutex); retry: - rcu_read_lock(); - list_for_each_entry_rcu(kip, &c->pages, list) { + list_for_each_entry(kip, &c->pages, list) { if (kip->nused < slots_per_page(c)) { int i; for (i = 0; i < slots_per_page(c); i++) { @@ -150,7 +149,6 @@ kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c) kip->slot_used[i] = SLOT_USED; kip->nused++; slot = kip->insns + (i * c->insn_size); - rcu_read_unlock(); goto out; } } @@ -159,7 +157,6 @@ kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c) WARN_ON(1); } } - rcu_read_unlock(); /* If there are any garbage slots, collect it and try again. */ if (c->nr_garbage && collect_garbage_slots(c) == 0) @@ -244,8 +241,7 @@ void __free_insn_slot(struct kprobe_insn_cache *c, long idx; mutex_lock(&c->mutex); - rcu_read_lock(); - list_for_each_entry_rcu(kip, &c->pages, list) { + list_for_each_entry(kip, &c->pages, list) { idx = ((long)slot - (long)kip->insns) / (c->insn_size * sizeof(kprobe_opcode_t)); if (idx >= 0 && idx < slots_per_page(c)) @@ -255,7 +251,6 @@ void __free_insn_slot(struct kprobe_insn_cache *c, WARN_ON(1); kip = NULL; out: - rcu_read_unlock(); /* Mark and sweep: this may sleep */ if (kip) { /* Check double free */