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[23.128.96.18]) by mx.google.com with ESMTP id a92si3856850edf.570.2021.01.28.10.21.29; Thu, 28 Jan 2021 10:21:55 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=casper.20170209 header.b=p4NhGTdU; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231691AbhA1SUT (ORCPT + 99 others); Thu, 28 Jan 2021 13:20:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35662 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231847AbhA1SRw (ORCPT ); Thu, 28 Jan 2021 13:17:52 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DA669C061786; Thu, 28 Jan 2021 10:15:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=tlNH0GImJ28FUndbA3Nv1X4L5OHbCQsFUKLhO1OFkXY=; b=p4NhGTdUZ5yI/Png3fjEr1fCfu V9Y1uE90oaupU7+h9ePNo6ZYLtcKnqgI1QtQ9dzSME8dW6l2dAD6lFOKBifKRKFf/7YpRoOs0nZDn BP+B0PPpTkH2l/mOhcJLlIKwMf8PaRi7EaEpWX2MSuf7Csiwevd3CMg56Vl2iwG3bsUcSv8s2+IdJ UFHbRAzkd7/orOa8xt4agB1HIpaRgE6I7iXE37dwyKhNOOv1kbMrdGLYjNAZphCivvkB+nBPLdr56 +JvnAMezZMcVdeXASaPjQL4c0DNF2AZqfOOC8te448vh8oWdarqhkSYV732DenTK53lfeHuN6uWDb hnRA/LOw==; Received: from [2001:4bb8:198:6bf4:e052:196b:7e32:37d9] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1l5Boi-008nrr-Uk; Thu, 28 Jan 2021 18:14:54 +0000 From: Christoph Hellwig To: Frederic Barrat , Andrew Donnellan , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , Jessica Yu , Josh Poimboeuf , Jiri Kosina , Miroslav Benes , Petr Mladek , Joe Lawrence Cc: Masahiro Yamada , Michal Marek , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, dri-devel@lists.freedesktop.org, live-patching@vger.kernel.org, linux-kbuild@vger.kernel.org Subject: [PATCH 04/13] module: use RCU to synchronize find_module Date: Thu, 28 Jan 2021 19:14:12 +0100 Message-Id: <20210128181421.2279-5-hch@lst.de> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210128181421.2279-1-hch@lst.de> References: <20210128181421.2279-1-hch@lst.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Allow for a RCU-sched critical section around find_module, following the lower level find_module_all helper, and switch the two callers outside of module.c to use such a RCU-sched critical section instead of module_mutex. Signed-off-by: Christoph Hellwig --- include/linux/module.h | 2 +- kernel/livepatch/core.c | 5 +++-- kernel/module.c | 1 - kernel/trace/trace_kprobe.c | 4 ++-- 4 files changed, 6 insertions(+), 6 deletions(-) diff --git a/include/linux/module.h b/include/linux/module.h index 7a0bcb5b1ffccd..a64aa84d1b182c 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -586,7 +586,7 @@ static inline bool within_module(unsigned long addr, const struct module *mod) return within_module_init(addr, mod) || within_module_core(addr, mod); } -/* Search for module by name: must hold module_mutex. */ +/* Search for module by name: must be in a RCU-sched critical section. */ struct module *find_module(const char *name); struct symsearch { diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index f76fdb9255323d..262cd9b003b9f0 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include "core.h" #include "patch.h" @@ -57,7 +58,7 @@ static void klp_find_object_module(struct klp_object *obj) if (!klp_is_module(obj)) return; - mutex_lock(&module_mutex); + rcu_read_lock_sched(); /* * We do not want to block removal of patched modules and therefore * we do not take a reference here. The patches are removed by @@ -74,7 +75,7 @@ static void klp_find_object_module(struct klp_object *obj) if (mod && mod->klp_alive) obj->mod = mod; - mutex_unlock(&module_mutex); + rcu_read_unlock_sched(); } static bool klp_initialized(void) diff --git a/kernel/module.c b/kernel/module.c index 981302f616b411..6772fb2680eb3e 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -668,7 +668,6 @@ static struct module *find_module_all(const char *name, size_t len, struct module *find_module(const char *name) { - module_assert_mutex(); return find_module_all(name, strlen(name), false); } diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index e6fba1798771b4..3137992baa5e7a 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -124,9 +124,9 @@ static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk) if (!p) return true; *p = '\0'; - mutex_lock(&module_mutex); + rcu_read_lock_sched(); ret = !!find_module(tk->symbol); - mutex_unlock(&module_mutex); + rcu_read_unlock_sched(); *p = ':'; return ret; -- 2.29.2