From patchwork Thu May 7 17:39:08 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 226310 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EC712C47257 for ; Thu, 7 May 2020 17:39:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D59F324958 for ; Thu, 7 May 2020 17:39:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727937AbgEGRjb (ORCPT ); Thu, 7 May 2020 13:39:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:35722 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727117AbgEGRja (ORCPT ); Thu, 7 May 2020 13:39:30 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0526724959; Thu, 7 May 2020 17:39:30 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.93) (envelope-from ) id 1jWkUa-000DnC-UH; Thu, 07 May 2020 13:39:28 -0400 Message-ID: <20200507173928.816083926@goodmis.org> User-Agent: quilt/0.66 Date: Thu, 07 May 2020 13:39:08 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Tom Zanussi , stable@vger.kernel.org, Masami Hiramatsu Subject: [for-linus][PATCH 4/9] tracing/kprobes: Reject new event if loc is NULL References: <20200507173904.729935165@goodmis.org> MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Masami Hiramatsu Reject the new event which has NULL location for kprobes. For kprobes, user must specify at least the location. Link: http://lkml.kernel.org/r/158779376597.6082.1411212055469099461.stgit@devnote2 Cc: Tom Zanussi Cc: Ingo Molnar Cc: stable@vger.kernel.org Fixes: 2a588dd1d5d6 ("tracing: Add kprobe event command generation functions") Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_kprobe.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 0d9300c3b084..35989383ae11 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -940,6 +940,9 @@ EXPORT_SYMBOL_GPL(kprobe_event_cmd_init); * complete command or only the first part of it; in the latter case, * kprobe_event_add_fields() can be used to add more fields following this. * + * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This + * returns -EINVAL if @loc == NULL. + * * Return: 0 if successful, error otherwise. */ int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe, @@ -953,6 +956,9 @@ int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe, if (cmd->type != DYNEVENT_TYPE_KPROBE) return -EINVAL; + if (!loc) + return -EINVAL; + if (kretprobe) snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name); else From patchwork Thu May 7 17:39:09 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 226308 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AFAFEC38A24 for ; Thu, 7 May 2020 17:40:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9C79F20735 for ; Thu, 7 May 2020 17:40:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728119AbgEGRj6 (ORCPT ); Thu, 7 May 2020 13:39:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:35750 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727825AbgEGRja (ORCPT ); Thu, 7 May 2020 13:39:30 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 307E8215A4; Thu, 7 May 2020 17:39:30 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.93) (envelope-from ) id 1jWkUb-000Dni-3C; Thu, 07 May 2020 13:39:29 -0400 Message-ID: <20200507173928.961003729@goodmis.org> User-Agent: quilt/0.66 Date: Thu, 07 May 2020 13:39:09 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , stable@vger.kernel.org, Xiao Yang , Joel Fernandes Subject: [for-linus][PATCH 5/9] tracing: Wait for preempt irq delay thread to finish References: <20200507173904.729935165@goodmis.org> MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: "Steven Rostedt (VMware)" Running on a slower machine, it is possible that the preempt delay kernel thread may still be executing if the module was immediately removed after added, and this can cause the kernel to crash as the kernel thread might be executing after its code has been removed. There's no reason that the caller of the code shouldn't just wait for the delay thread to finish, as the thread can also be created by a trigger in the sysfs code, which also has the same issues. Link: http://lore.kernel.org/r/5EA2B0C8.2080706@cn.fujitsu.com Cc: stable@vger.kernel.org Fixes: 793937236d1ee ("lib: Add module for testing preemptoff/irqsoff latency tracers") Reported-by: Xiao Yang Reviewed-by: Xiao Yang Reviewed-by: Joel Fernandes Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/preemptirq_delay_test.c | 30 ++++++++++++++++++++++------ 1 file changed, 24 insertions(+), 6 deletions(-) diff --git a/kernel/trace/preemptirq_delay_test.c b/kernel/trace/preemptirq_delay_test.c index 31c0fad4cb9e..c4c86de63cf9 100644 --- a/kernel/trace/preemptirq_delay_test.c +++ b/kernel/trace/preemptirq_delay_test.c @@ -113,22 +113,42 @@ static int preemptirq_delay_run(void *data) for (i = 0; i < s; i++) (testfuncs[i])(i); + + set_current_state(TASK_INTERRUPTIBLE); + while (!kthread_should_stop()) { + schedule(); + set_current_state(TASK_INTERRUPTIBLE); + } + + __set_current_state(TASK_RUNNING); + return 0; } -static struct task_struct *preemptirq_start_test(void) +static int preemptirq_run_test(void) { + struct task_struct *task; + char task_name[50]; snprintf(task_name, sizeof(task_name), "%s_test", test_mode); - return kthread_run(preemptirq_delay_run, NULL, task_name); + task = kthread_run(preemptirq_delay_run, NULL, task_name); + if (IS_ERR(task)) + return PTR_ERR(task); + if (task) + kthread_stop(task); + return 0; } static ssize_t trigger_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { - preemptirq_start_test(); + ssize_t ret; + + ret = preemptirq_run_test(); + if (ret) + return ret; return count; } @@ -148,11 +168,9 @@ static struct kobject *preemptirq_delay_kobj; static int __init preemptirq_delay_init(void) { - struct task_struct *test_task; int retval; - test_task = preemptirq_start_test(); - retval = PTR_ERR_OR_ZERO(test_task); + retval = preemptirq_run_test(); if (retval != 0) return retval; From patchwork Thu May 7 17:39:10 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 226309 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B9A10C38A24 for ; Thu, 7 May 2020 17:39:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 93217221F7 for ; Thu, 7 May 2020 17:39:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728068AbgEGRjk (ORCPT ); Thu, 7 May 2020 13:39:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:35774 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726491AbgEGRja (ORCPT ); Thu, 7 May 2020 13:39:30 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 58A02218AC; Thu, 7 May 2020 17:39:30 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.93) (envelope-from ) id 1jWkUb-000DoE-7b; Thu, 07 May 2020 13:39:29 -0400 Message-ID: <20200507173929.118079761@goodmis.org> User-Agent: quilt/0.66 Date: Thu, 07 May 2020 13:39:10 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , stable@vger.kernel.org, "Tzvetomir Stoyanov (VMware)" , Joerg Roedel Subject: [for-linus][PATCH 6/9] tracing: Add a vmalloc_sync_mappings() for safe measure References: <20200507173904.729935165@goodmis.org> MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: "Steven Rostedt (VMware)" x86_64 lazily maps in the vmalloc pages, and the way this works with per_cpu areas can be complex, to say the least. Mappings may happen at boot up, and if nothing synchronizes the page tables, those page mappings may not be synced till they are used. This causes issues for anything that might touch one of those mappings in the path of the page fault handler. When one of those unmapped mappings is touched in the page fault handler, it will cause another page fault, which in turn will cause a page fault, and leave us in a loop of page faults. Commit 763802b53a42 ("x86/mm: split vmalloc_sync_all()") split vmalloc_sync_all() into vmalloc_sync_unmappings() and vmalloc_sync_mappings(), as on system exit, it did not need to do a full sync on x86_64 (although it still needed to be done on x86_32). By chance, the vmalloc_sync_all() would synchronize the page mappings done at boot up and prevent the per cpu area from being a problem for tracing in the page fault handler. But when that synchronization in the exit of a task became a nop, it caused the problem to appear. Link: https://lore.kernel.org/r/20200429054857.66e8e333@oasis.local.home Cc: stable@vger.kernel.org Fixes: 737223fbca3b1 ("tracing: Consolidate buffer allocation code") Reported-by: "Tzvetomir Stoyanov (VMware)" Suggested-by: Joerg Roedel Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 8d2b98812625..9ed6d92768af 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -8525,6 +8525,19 @@ static int allocate_trace_buffers(struct trace_array *tr, int size) */ allocate_snapshot = false; #endif + + /* + * Because of some magic with the way alloc_percpu() works on + * x86_64, we need to synchronize the pgd of all the tables, + * otherwise the trace events that happen in x86_64 page fault + * handlers can't cope with accessing the chance that a + * alloc_percpu()'d memory might be touched in the page fault trace + * event. Oh, and we need to audit all other alloc_percpu() and vmalloc() + * calls in tracing, because something might get triggered within a + * page fault trace event! + */ + vmalloc_sync_mappings(); + return 0; }