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 C818A1D6DB4; Wed, 5 Mar 2025 18:01:16 +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=1741197678; cv=none; b=cFeUDAoWRkt2Zbdb8KriOnnxIcqpfIbvEYK9HIlLGmZQIhRQaXuqwp/MDYySCitFUAFDs6NyrzB3sxEAQ+Nk3Vt2NnEjNanSXs2U9NKiG3+GtonPpjtoTvrCnIbSPbCGFoDmDrW2h8YCvaI46gyyVXQxG4A+dlR77nbfjyh6TkU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741197678; c=relaxed/simple; bh=FJ0Oy/jftO4Fthfd1LlS38OsbywW6Zqrdbof+LG5oX8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ExxoLcWuHV9kUOU4Iq/kuajWrwGK6SG7nyD8NyZw7a8hVU0ZmhnZeEOlkGIf3s1oMdbPf3DF2odsWNS3qzyjnObw3xip1XTtftVH+3t3tTM5I2a1QeYbbp+pZoCUmXjx6wKKtQZd0HCHZq7qVmtChQNJc8MzNeZDmW6DpkBxlfg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=s9EVfDnU; 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="s9EVfDnU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D6B73C4CED1; Wed, 5 Mar 2025 18:01:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741197676; bh=FJ0Oy/jftO4Fthfd1LlS38OsbywW6Zqrdbof+LG5oX8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=s9EVfDnUXrtX2YpVVm+SMs/C2+d5eFS+ivKnB3mk+5QkWAU4u4dnxZRzupWMhkAM9 bTZxvEnt5YBl///3/vdsl+kXzIw9pj9HQ9hvBGXGA751NY72UjL430l3dxKNlIndUf JVcIpKMz5iOfUJ0Bw8qgbd9d3DVAqoeIKzOMeCts= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Masami Hiramatsu , Mathieu Desnoyers , Tomas Glozar , Tom Zanussi , "Steven Rostedt (Google)" Subject: [PATCH 6.6 061/142] tracing: Fix bad hist from corrupting named_triggers list Date: Wed, 5 Mar 2025 18:48:00 +0100 Message-ID: <20250305174502.790136891@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250305174500.327985489@linuxfoundation.org> References: <20250305174500.327985489@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Steven Rostedt commit 6f86bdeab633a56d5c6dccf1a2c5989b6a5e323e upstream. The following commands causes a crash: ~# cd /sys/kernel/tracing/events/rcu/rcu_callback ~# echo 'hist:name=bad:keys=common_pid:onmax(bogus).save(common_pid)' > trigger bash: echo: write error: Invalid argument ~# echo 'hist:name=bad:keys=common_pid' > trigger Because the following occurs: event_trigger_write() { trigger_process_regex() { event_hist_trigger_parse() { data = event_trigger_alloc(..); event_trigger_register(.., data) { cmd_ops->reg(.., data, ..) [hist_register_trigger()] { data->ops->init() [event_hist_trigger_init()] { save_named_trigger(name, data) { list_add(&data->named_list, &named_triggers); } } } } ret = create_actions(); (return -EINVAL) if (ret) goto out_unreg; [..] ret = hist_trigger_enable(data, ...) { list_add_tail_rcu(&data->list, &file->triggers); <<<---- SKIPPED!!! (this is important!) [..] out_unreg: event_hist_unregister(.., data) { cmd_ops->unreg(.., data, ..) [hist_unregister_trigger()] { list_for_each_entry(iter, &file->triggers, list) { if (!hist_trigger_match(data, iter, named_data, false)) <- never matches continue; [..] test = iter; } if (test && test->ops->free) <<<-- test is NULL test->ops->free(test) [event_hist_trigger_free()] { [..] if (data->name) del_named_trigger(data) { list_del(&data->named_list); <<<<-- NEVER gets removed! } } } } [..] kfree(data); <<<-- frees item but it is still on list The next time a hist with name is registered, it causes an u-a-f bug and the kernel can crash. Move the code around such that if event_trigger_register() succeeds, the next thing called is hist_trigger_enable() which adds it to the list. A bunch of actions is called if get_named_trigger_data() returns false. But that doesn't need to be called after event_trigger_register(), so it can be moved up, allowing event_trigger_register() to be called just before hist_trigger_enable() keeping them together and allowing the file->triggers to be properly populated. Cc: stable@vger.kernel.org Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Link: https://lore.kernel.org/20250227163944.1c37f85f@gandalf.local.home Fixes: 067fe038e70f6 ("tracing: Add variable reference handling to hist triggers") Reported-by: Tomas Glozar Tested-by: Tomas Glozar Reviewed-by: Tom Zanussi Closes: https://lore.kernel.org/all/CAP4=nvTsxjckSBTz=Oe_UYh8keD9_sZC4i++4h72mJLic4_W4A@mail.gmail.com/ Signed-off-by: Steven Rostedt (Google) Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace_events_hist.c | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -6660,27 +6660,27 @@ static int event_hist_trigger_parse(stru if (existing_hist_update_only(glob, trigger_data, file)) goto out_free; - ret = event_trigger_register(cmd_ops, file, glob, trigger_data); - if (ret < 0) - goto out_free; + if (!get_named_trigger_data(trigger_data)) { - if (get_named_trigger_data(trigger_data)) - goto enable; + ret = create_actions(hist_data); + if (ret) + goto out_free; - ret = create_actions(hist_data); - if (ret) - goto out_unreg; + if (has_hist_vars(hist_data) || hist_data->n_var_refs) { + ret = save_hist_vars(hist_data); + if (ret) + goto out_free; + } - if (has_hist_vars(hist_data) || hist_data->n_var_refs) { - ret = save_hist_vars(hist_data); + ret = tracing_map_init(hist_data->map); if (ret) - goto out_unreg; + goto out_free; } - ret = tracing_map_init(hist_data->map); - if (ret) - goto out_unreg; -enable: + ret = event_trigger_register(cmd_ops, file, glob, trigger_data); + if (ret < 0) + goto out_free; + ret = hist_trigger_enable(trigger_data, file); if (ret) goto out_unreg;