From mboxrd@z Thu Jan 1 00:00:00 1970 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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 6F86CC432C0 for ; Mon, 2 Dec 2019 20:03:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 385FD215E5 for ; Mon, 2 Dec 2019 20:03:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575317027; bh=ObMQXij7UNQyPLmBCJawoB22jXPqknRYW9MQXk1d6Qc=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=fWsaefmy6lqfqtsnlWh6QkLI0SB/ylFTtU/cMXs+LCMbnICQbJ1Xjh3WpsY4WeYIQ hBbSzX7M5o3mbH/SI5Osy6CifLalUnaGUVAv+ztAHA1Kmbp/nXtb4cOQl5lWKkOLBM WYDmIkaUFt5nBe/DgXOd+El7CaD9GwFltWIpR2gc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728148AbfLBUDq (ORCPT ); Mon, 2 Dec 2019 15:03:46 -0500 Received: from mail.kernel.org ([198.145.29.99]:40698 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728001AbfLBUDq (ORCPT ); Mon, 2 Dec 2019 15:03:46 -0500 Received: from paulmck-ThinkPad-P72.home (50-39-105-78.bvtn.or.frontiernet.net [50.39.105.78]) (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 54486214AF; Mon, 2 Dec 2019 20:03:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575317025; bh=ObMQXij7UNQyPLmBCJawoB22jXPqknRYW9MQXk1d6Qc=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=eeu9wllFSpwrVG7DeebZ5Kk2eE76wfP+aPTiq/70Oa3FBMABvq74LbN7CV6LzaErn UrKFBnBIsMTtMy4c7VHElAOz0eGtl7AGFkxNlXF5LiHLuOTASkZkzs76jigYBW+5kM XmUrwHFaRvJ5BwawvdGjQ7qFys7RX0qRI7/BSGzg= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id 207AA3520649; Mon, 2 Dec 2019 12:03:45 -0800 (PST) Date: Mon, 2 Dec 2019 12:03:45 -0800 From: "Paul E. McKenney" To: Konstantin Khlebnikov Cc: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Sasha Levin , Kees Cook , Greg Kroah-Hartman , rcu@vger.kernel.org, Tejun Heo , Andrew Morton , Linus Torvalds , Thomas Gleixner Subject: Re: [PATCH 1/2] kernel: set taint flag 'L' at any kind of lockup Message-ID: <20191202200345.GV2889@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <157503370645.8187.6335564487789994134.stgit@buzz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <157503370645.8187.6335564487789994134.stgit@buzz> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Fri, Nov 29, 2019 at 04:21:46PM +0300, Konstantin Khlebnikov wrote: > Any lockup or stall notifies about unexpected lack of progress. > It's better to know about them for further problem investigations. > > Right now only softlockup has own taint flag. Let's generalize it. > > This patch renames TAINT_SOFTLOCKUP into TAINT_LOCKUP at sets it for: > - softlockup > - hardlockup > - RCU stalls > - stuck in workqueues > - detected task hung > > Signed-off-by: Konstantin Khlebnikov >From an RCU perspective, Acked-by: Paul E. McKenney > --- > Documentation/admin-guide/sysctl/kernel.rst | 2 +- > Documentation/admin-guide/tainted-kernels.rst | 8 ++++++-- > include/linux/kernel.h | 2 +- > kernel/hung_task.c | 2 ++ > kernel/panic.c | 2 +- > kernel/rcu/tree_stall.h | 1 + > kernel/watchdog.c | 2 +- > kernel/watchdog_hld.c | 1 + > kernel/workqueue.c | 1 + > tools/debugging/kernel-chktaint | 2 +- > 10 files changed, 16 insertions(+), 7 deletions(-) > > diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst > index 032c7cd3cede..60867ec525a4 100644 > --- a/Documentation/admin-guide/sysctl/kernel.rst > +++ b/Documentation/admin-guide/sysctl/kernel.rst > @@ -1082,7 +1082,7 @@ ORed together. The letters are seen in "Tainted" line of Oops reports. > 2048 `(I)` workaround for bug in platform firmware applied > 4096 `(O)` externally-built ("out-of-tree") module was loaded > 8192 `(E)` unsigned module was loaded > - 16384 `(L)` soft lockup occurred > + 16384 `(L)` lockup occurred > 32768 `(K)` kernel has been live patched > 65536 `(X)` Auxiliary taint, defined and used by for distros > 131072 `(T)` The kernel was built with the struct randomization plugin > diff --git a/Documentation/admin-guide/tainted-kernels.rst b/Documentation/admin-guide/tainted-kernels.rst > index 71e9184a9079..fc76d0aad9f5 100644 > --- a/Documentation/admin-guide/tainted-kernels.rst > +++ b/Documentation/admin-guide/tainted-kernels.rst > @@ -96,7 +96,7 @@ Bit Log Number Reason that got the kernel tainted > 11 _/I 2048 workaround for bug in platform firmware applied > 12 _/O 4096 externally-built ("out-of-tree") module was loaded > 13 _/E 8192 unsigned module was loaded > - 14 _/L 16384 soft lockup occurred > + 14 _/L 16384 lockup occurred > 15 _/K 32768 kernel has been live patched > 16 _/X 65536 auxiliary taint, defined for and used by distros > 17 _/T 131072 kernel was built with the struct randomization plugin > @@ -152,7 +152,11 @@ More detailed explanation for tainting > 13) ``E`` if an unsigned module has been loaded in a kernel supporting > module signature. > > - 14) ``L`` if a soft lockup has previously occurred on the system. > + 14) ``L`` if some kind of lockup has previously occurred on the system: > + - soft/hardlockup, see Documentation/admin-guide/lockup-watchdogs.rst > + - RCU stall, see Documentation/RCU/stallwarn.txt > + - hung task detected, see CONFIG_DETECT_HUNG_TASK > + - kernel workqueue lockup, see CONFIG_WQ_WATCHDOG > > 15) ``K`` if the kernel has been live patched. > > diff --git a/include/linux/kernel.h b/include/linux/kernel.h > index d83d403dac2e..e8a6808e4f2f 100644 > --- a/include/linux/kernel.h > +++ b/include/linux/kernel.h > @@ -591,7 +591,7 @@ extern enum system_states { > #define TAINT_FIRMWARE_WORKAROUND 11 > #define TAINT_OOT_MODULE 12 > #define TAINT_UNSIGNED_MODULE 13 > -#define TAINT_SOFTLOCKUP 14 > +#define TAINT_LOCKUP 14 > #define TAINT_LIVEPATCH 15 > #define TAINT_AUX 16 > #define TAINT_RANDSTRUCT 17 > diff --git a/kernel/hung_task.c b/kernel/hung_task.c > index 14a625c16cb3..521eb2fbf5fc 100644 > --- a/kernel/hung_task.c > +++ b/kernel/hung_task.c > @@ -139,6 +139,8 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout) > hung_task_show_lock = true; > } > > + add_taint(TAINT_LOCKUP, LOCKDEP_STILL_OK); > + > touch_nmi_watchdog(); > } > > diff --git a/kernel/panic.c b/kernel/panic.c > index f470a038b05b..d7750a45ca8d 100644 > --- a/kernel/panic.c > +++ b/kernel/panic.c > @@ -372,7 +372,7 @@ const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = { > [ TAINT_FIRMWARE_WORKAROUND ] = { 'I', ' ', false }, > [ TAINT_OOT_MODULE ] = { 'O', ' ', true }, > [ TAINT_UNSIGNED_MODULE ] = { 'E', ' ', true }, > - [ TAINT_SOFTLOCKUP ] = { 'L', ' ', false }, > + [ TAINT_LOCKUP ] = { 'L', ' ', false }, > [ TAINT_LIVEPATCH ] = { 'K', ' ', true }, > [ TAINT_AUX ] = { 'X', ' ', true }, > [ TAINT_RANDSTRUCT ] = { 'T', ' ', true }, > diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h > index c0b8c458d8a6..181495efff80 100644 > --- a/kernel/rcu/tree_stall.h > +++ b/kernel/rcu/tree_stall.h > @@ -74,6 +74,7 @@ early_initcall(check_cpu_stall_init); > /* If so specified via sysctl, panic, yielding cleaner stall-warning output. */ > static void panic_on_rcu_stall(void) > { > + add_taint(TAINT_LOCKUP, LOCKDEP_STILL_OK); > if (sysctl_panic_on_rcu_stall) > panic("RCU Stall\n"); > } > diff --git a/kernel/watchdog.c b/kernel/watchdog.c > index f41334ef0971..d60b195708f7 100644 > --- a/kernel/watchdog.c > +++ b/kernel/watchdog.c > @@ -466,7 +466,7 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer) > smp_mb__after_atomic(); > } > > - add_taint(TAINT_SOFTLOCKUP, LOCKDEP_STILL_OK); > + add_taint(TAINT_LOCKUP, LOCKDEP_STILL_OK); > if (softlockup_panic) > panic("softlockup: hung tasks"); > __this_cpu_write(soft_watchdog_warn, true); > diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c > index 247bf0b1582c..f77256f47422 100644 > --- a/kernel/watchdog_hld.c > +++ b/kernel/watchdog_hld.c > @@ -152,6 +152,7 @@ static void watchdog_overflow_callback(struct perf_event *event, > !test_and_set_bit(0, &hardlockup_allcpu_dumped)) > trigger_allbutself_cpu_backtrace(); > > + add_taint(TAINT_LOCKUP, LOCKDEP_STILL_OK); > if (hardlockup_panic) > nmi_panic(regs, "Hard LOCKUP"); > > diff --git a/kernel/workqueue.c b/kernel/workqueue.c > index bc2e09a8ea61..825a92893882 100644 > --- a/kernel/workqueue.c > +++ b/kernel/workqueue.c > @@ -5741,6 +5741,7 @@ static void wq_watchdog_timer_fn(struct timer_list *unused) > pr_cont_pool_info(pool); > pr_cont(" stuck for %us!\n", > jiffies_to_msecs(jiffies - pool_ts) / 1000); > + add_taint(TAINT_LOCKUP, LOCKDEP_STILL_OK); > } > } > > diff --git a/tools/debugging/kernel-chktaint b/tools/debugging/kernel-chktaint > index 2240cb56e6e5..9f24719d8c80 100755 > --- a/tools/debugging/kernel-chktaint > +++ b/tools/debugging/kernel-chktaint > @@ -168,7 +168,7 @@ if [ `expr $T % 2` -eq 0 ]; then > addout " " > else > addout "L" > - echo " * soft lockup occurred (#14)" > + echo " * lockup occurred (#14)" > fi > > T=`expr $T / 2` >