From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:38702 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759352AbdEWSkR (ORCPT ); Tue, 23 May 2017 14:40:17 -0400 Subject: Patch "tracing/kprobes: Enforce kprobes teardown after testing" has been added to the 4.9-stable tree To: tglx@linutronix.de, gregkh@linuxfoundation.org, mhiramat@kernel.org, rostedt@goodmis.org Cc: , From: Date: Tue, 23 May 2017 20:38:18 +0200 Message-ID: <149556469875161@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled tracing/kprobes: Enforce kprobes teardown after testing to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: tracing-kprobes-enforce-kprobes-teardown-after-testing.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 30e7d894c1478c88d50ce94ddcdbd7f9763d9cdd Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 17 May 2017 10:19:49 +0200 Subject: tracing/kprobes: Enforce kprobes teardown after testing From: Thomas Gleixner commit 30e7d894c1478c88d50ce94ddcdbd7f9763d9cdd upstream. Enabling the tracer selftest triggers occasionally the warning in text_poke(), which warns when the to be modified page is not marked reserved. The reason is that the tracer selftest installs kprobes on functions marked __init for testing. These probes are removed after the tests, but that removal schedules the delayed kprobes_optimizer work, which will do the actual text poke. If the work is executed after the init text is freed, then the warning triggers. The bug can be reproduced reliably when the work delay is increased. Flush the optimizer work and wait for the optimizing/unoptimizing lists to become empty before returning from the kprobes tracer selftest. That ensures that all operations which were queued due to the probes removal have completed. Link: http://lkml.kernel.org/r/20170516094802.76a468bb@gandalf.local.home Signed-off-by: Thomas Gleixner Acked-by: Masami Hiramatsu Fixes: 6274de498 ("kprobes: Support delayed unoptimizing") Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman --- include/linux/kprobes.h | 4 +++- kernel/kprobes.c | 2 +- kernel/trace/trace_kprobe.c | 5 +++++ 3 files changed, 9 insertions(+), 2 deletions(-) --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -330,7 +330,9 @@ extern int proc_kprobes_optimization_han int write, void __user *buffer, size_t *length, loff_t *ppos); #endif - +extern void wait_for_kprobe_optimizer(void); +#else +static inline void wait_for_kprobe_optimizer(void) { } #endif /* CONFIG_OPTPROBES */ #ifdef CONFIG_KPROBES_ON_FTRACE extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -563,7 +563,7 @@ static void kprobe_optimizer(struct work } /* Wait for completing optimization and unoptimization */ -static void wait_for_kprobe_optimizer(void) +void wait_for_kprobe_optimizer(void) { mutex_lock(&kprobe_mutex); --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1484,6 +1484,11 @@ static __init int kprobe_trace_self_test end: release_all_trace_kprobes(); + /* + * Wait for the optimizer work to finish. Otherwise it might fiddle + * with probes in already freed __init text. + */ + wait_for_kprobe_optimizer(); if (warn) pr_cont("NG: Some tests are failed. Please check them.\n"); else Patches currently in stable-queue which might be from tglx@linutronix.de are queue-4.9/stackprotector-increase-the-per-task-stack-canary-s-random-range-from-32-bits-to-64-bits-on-64-bit-platforms.patch queue-4.9/genirq-fix-chained-interrupt-data-ordering.patch queue-4.9/tracing-kprobes-enforce-kprobes-teardown-after-testing.patch