From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 8F80F2D0626; Tue, 26 Aug 2025 14:42:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756219341; cv=none; b=TyHU45AAy1g7J/g+VJgYRmxdGWoR0yBuEm0qQuIgwcQoAubSU3TybbUmRb826lu1PFZZ5pyEYJSpu8ZPDaTYLqiBM/AF4febyVItY2SjwE2gI3sC9EoLJCoIhqKmjo2r9EUnvw8ma6n1Ipxzj6eLqPSWHHSHHlGLVmdT37sPHjI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756219341; c=relaxed/simple; bh=nhlr0Z8DGhI8XZCb/d19XX+OZK88ZxIjX+pG5N2KQnY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=d4dgtD5FXB2cTLdmId5DvgEVo0eqjOVddTrTqf9uTuZSwp4cnLlBdUGDu9wReeY4M/0nXFhmviqRKtqA9JUiHs1dxvyS8/vq95nXikA3ilfu1PRc4xDeTdoJ66czwtlPgjBdoTAZnvvXRCUpum15Gd8CPWNpBkmEeN+r1UGNjAs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=eL+CRNbD; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="eL+CRNbD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1DF9FC4CEF1; Tue, 26 Aug 2025 14:42:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756219341; bh=nhlr0Z8DGhI8XZCb/d19XX+OZK88ZxIjX+pG5N2KQnY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eL+CRNbDtuCc9p5NyveAiYTYAQow/cZvT+9v1XgFnaL9ZMtiCOoL4IeDlMGYpVSsr /5gw8sENqGjy1jOTcU1HuzSk3PSRjrNenxaQwIAGWBlw8ln3K+cn6jflTpXw7FVXXo Ogl/OUVhCjMJvrbdBPASfHanJt4LzQnB1BOYhGZY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mathieu Desnoyers , "Masami Hiramatsu (Google)" , =?UTF-8?q?Fusheng=20Huang ?= , "Steven Rostedt (Google)" , Sasha Levin Subject: [PATCH 5.4 344/403] tracing: Add down_write(trace_event_sem) when adding trace event Date: Tue, 26 Aug 2025 13:11:10 +0200 Message-ID: <20250826110916.365860099@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110905.607690791@linuxfoundation.org> References: <20250826110905.607690791@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Steven Rostedt [ Upstream commit b5e8acc14dcb314a9b61ff19dcd9fdd0d88f70df ] When a module is loaded, it adds trace events defined by the module. It may also need to modify the modules trace printk formats to replace enum names with their values. If two modules are loaded at the same time, the adding of the event to the ftrace_events list can corrupt the walking of the list in the code that is modifying the printk format strings and crash the kernel. The addition of the event should take the trace_event_sem for write while it adds the new event. Also add a lockdep_assert_held() on that semaphore in __trace_add_event_dirs() as it iterates the list. Cc: stable@vger.kernel.org Cc: Mathieu Desnoyers Acked-by: Masami Hiramatsu (Google) Link: https://lore.kernel.org/20250718223158.799bfc0c@batman.local.home Reported-by: Fusheng Huang(黄富生) Closes: https://lore.kernel.org/all/20250717105007.46ccd18f@batman.local.home/ Fixes: 110bf2b764eb6 ("tracing: add protection around module events unload") Signed-off-by: Steven Rostedt (Google) Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace_events.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -2109,7 +2109,10 @@ __register_event(struct trace_event_call if (ret < 0) return ret; + down_write(&trace_event_sem); list_add(&call->list, &ftrace_events); + up_write(&trace_event_sem); + call->mod = mod; return 0; @@ -2489,6 +2492,8 @@ __trace_add_event_dirs(struct trace_arra struct trace_event_call *call; int ret; + lockdep_assert_held(&trace_event_sem); + list_for_each_entry(call, &ftrace_events, list) { ret = __trace_add_new_event(call, tr); if (ret < 0)