From patchwork Fri Dec 20 17:41:38 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 13917190 X-Patchwork-Delegate: bpf@iogearbox.net Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AD6D7228C87; Fri, 20 Dec 2024 17:47:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734716870; cv=none; b=uNSAzK9P9Z3feeYMLX2XXluL3k1ONQq5LXjnJBBdcauW4NmZYNKDs9uNdwZXtJV5LQTd2ELBQcHo51QFWm6jGYkcqGMcXtOFlsORjognVeQEwMuxOPS7mHmctlAbO0dlUV0m/Gwk9KN44cbANWjP6JT7xDdlRV15xAKGQ9QEqLg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734716870; c=relaxed/simple; bh=wT1uBpL1/SaJ4hNyMwwXG5byQc1hQ2W8jUnWEH+nwtM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=k/VwdXURULv5F7UEaCTIjoSRFfPbD0gCWwIiPgujIH7zcIfJRQGBP9rm/lza3mSt9CAMQWdIdIOwzCf6SCRhtedJNWJev7dEPizmNkClWOQSw0TViil960aWZrhh8hm/x+5HdK9ls8f3PmQ0J4j01PRttX6ZCamqxfcc8EzcyxI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=D9ahDB8R; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=eeW9haKq; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="D9ahDB8R"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="eeW9haKq" From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1734716866; 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=kG1v1wu3D3TuS8vhLDHRaF7dmu7B/vJ02VdgW4EZUoE=; b=D9ahDB8RXZP0FtEdc1K/ru4TjyLny1CvEWUccj/8qDL3JOmdQaKnqUfVD+5Zf0NP14XOT8 +eZxOXzNIomH4vyUH6d44nxYhI9Tnx2s+fjaxsPcggMHo9qLDKNgRq+CeHKYvmZsHLdOPF Lb/lnZI2q8y/5ia53tHAYCkzI3WCK1ZwJ5yj11d5ejhwHCoJ4vid/pBXEnpVC7R+hRZX7s Luz0K3hLjrUdbXIyFPsl3KxB9Zts77Mt+5pn43WXjGRppaMGptPmPplypEE6R5iVcHIpQ7 /OPg0nGDhabIy9XwWkOESpRLMsFqRH2qhMn5fhfFV2qD/micRXTaG6Xo0btN8Q== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1734716866; 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=kG1v1wu3D3TuS8vhLDHRaF7dmu7B/vJ02VdgW4EZUoE=; b=eeW9haKq3KowFdehTfjJFroB4yIBxuCgvJQQ+lUIH+tMDD5bZ+6Vyrs8xQNLbZj+YfH9cM 45VM35EtlGj7qmBg== To: linux-modules@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Daniel Gomez , Luis Chamberlain , "Paul E . McKenney" , Peter Zijlstra , Petr Pavlu , Sami Tolvanen , Thomas Gleixner , Sebastian Andrzej Siewior , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Eduard Zingerman , Hao Luo , Jiri Olsa , John Fastabend , KP Singh , Martin KaFai Lau , Masami Hiramatsu , Mathieu Desnoyers , Matt Bobrowski , Song Liu , Stanislav Fomichev , Steven Rostedt , Yonghong Song , bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH v2 24/28] bpf: Use RCU in all users of __module_text_address(). Date: Fri, 20 Dec 2024 18:41:38 +0100 Message-ID: <20241220174731.514432-25-bigeasy@linutronix.de> In-Reply-To: <20241220174731.514432-1-bigeasy@linutronix.de> References: <20241220174731.514432-1-bigeasy@linutronix.de> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net __module_address() can be invoked within a RCU section, there is no requirement to have preemption disabled. Replace the preempt_disable() section around __module_address() with RCU. Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Daniel Borkmann Cc: Eduard Zingerman Cc: Hao Luo Cc: Jiri Olsa Cc: John Fastabend Cc: KP Singh Cc: Martin KaFai Lau Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Matt Bobrowski Cc: Song Liu Cc: Stanislav Fomichev Cc: Steven Rostedt Cc: Yonghong Song Cc: bpf@vger.kernel.org Cc: linux-trace-kernel@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior --- kernel/trace/bpf_trace.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 1b8db5aee9d38..020df7b6ff90c 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2336,10 +2336,9 @@ void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp) { struct module *mod; - preempt_disable(); + guard(rcu)(); mod = __module_address((unsigned long)btp); module_put(mod); - preempt_enable(); } static __always_inline @@ -2907,16 +2906,14 @@ static int get_modules_for_addrs(struct module ***mods, unsigned long *addrs, u3 for (i = 0; i < addrs_cnt; i++) { struct module *mod; - preempt_disable(); - mod = __module_address(addrs[i]); - /* Either no module or we it's already stored */ - if (!mod || has_module(&arr, mod)) { - preempt_enable(); - continue; + scoped_guard(rcu) { + mod = __module_address(addrs[i]); + /* Either no module or we it's already stored */ + if (!mod || has_module(&arr, mod)) + continue; + if (!try_module_get(mod)) + err = -EINVAL; } - if (!try_module_get(mod)) - err = -EINVAL; - preempt_enable(); if (err) break; err = add_module(&arr, mod);