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 A736E27D764; Tue, 8 Apr 2025 12:59:09 +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=1744117149; cv=none; b=TzMU6/6vc/YrNQe4TyirDdbC10tnHjghA+Z+cpKVlnxERe76S3iv05OLGYs/4BK+KmgIHtNMjMxqOL8mhIGvR8p6qW/uOr/KVIA0xkl4Qaf14wyKpPo5KwbZ2K9jZ60kGJ2/WCRrd1sNlJS1b4f4owA8sbKaQh3dJhTAuqjs2CI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744117149; c=relaxed/simple; bh=/paaW65NxRk4wxVm8s7U6SW2sUr2oQpX5Z7AU+75fp8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=SvDDXM+YCbmVJmqe/LnNtIUrv0fSW+h2vENd4jllzWARxprpsnFWzHQUePLjIgIr4hBcnZ2dFBoibOV8Fvexcfp7s+HxHMyCnPmSfBVcJSJl+krsZMbYMffcKIdn1xKQTUYO0SXkxIW6/hWSsp3ziqEMVB2lY6y26sp8U+mUoRo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=VLlp+vax; 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="VLlp+vax" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2CF8EC4CEE5; Tue, 8 Apr 2025 12:59:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1744117149; bh=/paaW65NxRk4wxVm8s7U6SW2sUr2oQpX5Z7AU+75fp8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VLlp+vaxMr/RnHIYCkuBsglT09pKEB7GU0eoG5nbkCbL1XiLKHJQvyIwiAWsX0iWX BFs3lDnQtXweFdYUjDC2EcK2IfMUe6v43Mkjx6A9roWhD86h0QMwtF2yp6FfP/JJDe 3hnD5J9Suu33EO6vNVpwSMLynwGu67hOzEtEJ6b4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Masami Hiramatsu , Mathieu Desnoyers , Zheng Yejian , Kairui Song , Tengda Wu , "Steven Rostedt (Google)" Subject: [PATCH 6.12 403/423] tracing: Fix use-after-free in print_graph_function_flags during tracer switching Date: Tue, 8 Apr 2025 12:52:09 +0200 Message-ID: <20250408104855.295547493@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250408104845.675475678@linuxfoundation.org> References: <20250408104845.675475678@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-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tengda Wu commit 7f81f27b1093e4895e87b74143c59c055c3b1906 upstream. Kairui reported a UAF issue in print_graph_function_flags() during ftrace stress testing [1]. This issue can be reproduced if puting a 'mdelay(10)' after 'mutex_unlock(&trace_types_lock)' in s_start(), and executing the following script: $ echo function_graph > current_tracer $ cat trace > /dev/null & $ sleep 5 # Ensure the 'cat' reaches the 'mdelay(10)' point $ echo timerlat > current_tracer The root cause lies in the two calls to print_graph_function_flags within print_trace_line during each s_show(): * One through 'iter->trace->print_line()'; * Another through 'event->funcs->trace()', which is hidden in print_trace_fmt() before print_trace_line returns. Tracer switching only updates the former, while the latter continues to use the print_line function of the old tracer, which in the script above is print_graph_function_flags. Moreover, when switching from the 'function_graph' tracer to the 'timerlat' tracer, s_start only calls graph_trace_close of the 'function_graph' tracer to free 'iter->private', but does not set it to NULL. This provides an opportunity for 'event->funcs->trace()' to use an invalid 'iter->private'. To fix this issue, set 'iter->private' to NULL immediately after freeing it in graph_trace_close(), ensuring that an invalid pointer is not passed to other tracers. Additionally, clean up the unnecessary 'iter->private = NULL' during each 'cat trace' when using wakeup and irqsoff tracers. [1] https://lore.kernel.org/all/20231112150030.84609-1-ryncsn@gmail.com/ Cc: stable@vger.kernel.org Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Zheng Yejian Link: https://lore.kernel.org/20250320122137.23635-1-wutengda@huaweicloud.com Fixes: eecb91b9f98d ("tracing: Fix memleak due to race between current_tracer and trace") Closes: https://lore.kernel.org/all/CAMgjq7BW79KDSCyp+tZHjShSzHsScSiJxn5ffskp-QzVM06fxw@mail.gmail.com/ Reported-by: Kairui Song Signed-off-by: Tengda Wu Signed-off-by: Steven Rostedt (Google) Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace_functions_graph.c | 1 + kernel/trace/trace_irqsoff.c | 2 -- kernel/trace/trace_sched_wakeup.c | 2 -- 3 files changed, 1 insertion(+), 4 deletions(-) --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -1353,6 +1353,7 @@ void graph_trace_close(struct trace_iter if (data) { free_percpu(data->cpu_data); kfree(data); + iter->private = NULL; } } --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -233,8 +233,6 @@ static void irqsoff_trace_open(struct tr { if (is_graph(iter->tr)) graph_trace_open(iter); - else - iter->private = NULL; } static void irqsoff_trace_close(struct trace_iterator *iter) --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -170,8 +170,6 @@ static void wakeup_trace_open(struct tra { if (is_graph(iter->tr)) graph_trace_open(iter); - else - iter->private = NULL; } static void wakeup_trace_close(struct trace_iterator *iter)