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=-14.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 06B47C2BC11 for ; Mon, 14 Sep 2020 17:17:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BA71B206B7 for ; Mon, 14 Sep 2020 17:17:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="VkXkT75Z"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="tDupPXka" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726340AbgINRQn (ORCPT ); Mon, 14 Sep 2020 13:16:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35598 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726119AbgINRQY (ORCPT ); Mon, 14 Sep 2020 13:16:24 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8FE5CC06174A; Mon, 14 Sep 2020 10:16:16 -0700 (PDT) Date: Mon, 14 Sep 2020 17:16:13 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1600103774; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qJtndh+Q7qp0zrdIKsuoXHaaA83pQzXtPICKZCe8ap8=; b=VkXkT75ZCZ9JCSnDdKqYlOdra3UwR0RAkrFXAiz5FWv5ueGQ/IEqmIIbEs4b8HxmpxSklL qWM0fWAKXJiD5ZyT9vhMMf/mS+xEO448oDXdmTGYk2D82Sqf5YvNcl2i9wdNyGtkO2VMkP A1Q1Wgp08RtQzd7+QrVzzKFlG7b3HPaa5eTchg8mKEUnkFfo8E7WlEFKNJCua2RMbV280I BdGyW8PRbNAfPu9VWWuLe8FTBea1e5JhqmhM7c9wkQmHWVtcbFm/pIkf+L5zZqvZQLKp0s lPToIq3dsgnNQozP7Sn/d/wbdqQarCrC4bTvuAvhXSqFYG0OivkaK2lUpyUXEg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1600103774; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qJtndh+Q7qp0zrdIKsuoXHaaA83pQzXtPICKZCe8ap8=; b=tDupPXkaCvYBbHlSVwI0VHD91RNAws3L/HaduHYvWdZPuSsyGg9rCMFG03X8BPR8oeHIt2 B9Qh4/EB8S44BPCw== From: "tip-bot2 for Masami Hiramatsu" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: perf/kprobes] kprobes: Free kretprobe_instance with RCU callback Cc: Masami Hiramatsu , Ingo Molnar , x86 , LKML In-Reply-To: <159870616685.1229682.11978742048709542226.stgit@devnote2> References: <159870616685.1229682.11978742048709542226.stgit@devnote2> MIME-Version: 1.0 Message-ID: <160010377373.15536.15527515602738803514.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the perf/kprobes branch of tip: Commit-ID: b338817807538c893540e393856b79cbbdf777ea Gitweb: https://git.kernel.org/tip/b338817807538c893540e393856b79cbbdf777ea Author: Masami Hiramatsu AuthorDate: Sat, 29 Aug 2020 22:02:47 +09:00 Committer: Ingo Molnar CommitterDate: Tue, 08 Sep 2020 11:52:35 +02:00 kprobes: Free kretprobe_instance with RCU callback Free kretprobe_instance with RCU callback instead of directly freeing the object in the kretprobe handler context. This will make kretprobe run safer in NMI context. Signed-off-by: Masami Hiramatsu Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/159870616685.1229682.11978742048709542226.stgit@devnote2 --- include/linux/kprobes.h | 6 ++++-- kernel/kprobes.c | 25 ++++++------------------- 2 files changed, 10 insertions(+), 21 deletions(-) diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index 72142ae..3389067 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -156,7 +156,10 @@ struct kretprobe { }; struct kretprobe_instance { - struct hlist_node hlist; + union { + struct hlist_node hlist; + struct rcu_head rcu; + }; struct kretprobe *rp; kprobe_opcode_t *ret_addr; struct task_struct *task; @@ -395,7 +398,6 @@ int register_kretprobes(struct kretprobe **rps, int num); void unregister_kretprobes(struct kretprobe **rps, int num); void kprobe_flush_task(struct task_struct *tk); -void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head); int disable_kprobe(struct kprobe *kp); int enable_kprobe(struct kprobe *kp); diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 2111382..0676868 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1223,8 +1223,7 @@ void kprobes_inc_nmissed_count(struct kprobe *p) } NOKPROBE_SYMBOL(kprobes_inc_nmissed_count); -void recycle_rp_inst(struct kretprobe_instance *ri, - struct hlist_head *head) +static void recycle_rp_inst(struct kretprobe_instance *ri) { struct kretprobe *rp = ri->rp; @@ -1236,8 +1235,7 @@ void recycle_rp_inst(struct kretprobe_instance *ri, hlist_add_head(&ri->hlist, &rp->free_instances); raw_spin_unlock(&rp->lock); } else - /* Unregistering */ - hlist_add_head(&ri->hlist, head); + kfree_rcu(ri, rcu); } NOKPROBE_SYMBOL(recycle_rp_inst); @@ -1313,7 +1311,7 @@ void kprobe_busy_end(void) void kprobe_flush_task(struct task_struct *tk) { struct kretprobe_instance *ri; - struct hlist_head *head, empty_rp; + struct hlist_head *head; struct hlist_node *tmp; unsigned long hash, flags = 0; @@ -1323,19 +1321,14 @@ void kprobe_flush_task(struct task_struct *tk) kprobe_busy_begin(); - INIT_HLIST_HEAD(&empty_rp); hash = hash_ptr(tk, KPROBE_HASH_BITS); head = &kretprobe_inst_table[hash]; kretprobe_table_lock(hash, &flags); hlist_for_each_entry_safe(ri, tmp, head, hlist) { if (ri->task == tk) - recycle_rp_inst(ri, &empty_rp); + recycle_rp_inst(ri); } kretprobe_table_unlock(hash, &flags); - hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { - hlist_del(&ri->hlist); - kfree(ri); - } kprobe_busy_end(); } @@ -1936,13 +1929,12 @@ unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs, void *frame_pointer) { struct kretprobe_instance *ri = NULL, *last = NULL; - struct hlist_head *head, empty_rp; + struct hlist_head *head; struct hlist_node *tmp; unsigned long flags; kprobe_opcode_t *correct_ret_addr = NULL; bool skipped = false; - INIT_HLIST_HEAD(&empty_rp); kretprobe_hash_lock(current, &head, &flags); /* @@ -2011,7 +2003,7 @@ unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs, __this_cpu_write(current_kprobe, prev); } - recycle_rp_inst(ri, &empty_rp); + recycle_rp_inst(ri); if (ri == last) break; @@ -2019,11 +2011,6 @@ unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs, kretprobe_hash_unlock(current, &flags); - hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { - hlist_del(&ri->hlist); - kfree(ri); - } - return (unsigned long)correct_ret_addr; } NOKPROBE_SYMBOL(__kretprobe_trampoline_handler)