From: Dan Carpenter <dan.carpenter@oracle.com>
To: kbuild@lists.01.org, Zqiang <qiang1.zhang@intel.com>,
paulmck@kernel.org, frederic@kernel.org
Cc: lkp@intel.com, kbuild-all@lists.01.org, rcu@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] rcu: Dump all rcuc kthreads status for CPUs that not report quiescent state
Date: Mon, 25 Apr 2022 16:23:55 +0300 [thread overview]
Message-ID: <202204241503.imwh5SqZ-lkp@intel.com> (raw)
In-Reply-To: <20220424041747.3172671-1-qiang1.zhang@intel.com>
Hi Zqiang,
url: https://github.com/intel-lab-lkp/linux/commits/Zqiang/rcu-Dump-all-rcuc-kthreads-status-for-CPUs-that-not-report-quiescent-state/20220424-121850
base: https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev
config: i386-randconfig-m021 (https://download.01.org/0day-ci/archive/20220424/202204241503.imwh5SqZ-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.2.0-20) 11.2.0
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
smatch warnings:
kernel/rcu/tree_stall.h:467 print_cpu_stall_info() error: uninitialized symbol 'j'.
vim +/j +467 kernel/rcu/tree_stall.h
59b73a27681c58 Paul E. McKenney 2019-01-11 440 static void print_cpu_stall_info(int cpu)
59b73a27681c58 Paul E. McKenney 2019-01-11 441 {
59b73a27681c58 Paul E. McKenney 2019-01-11 442 unsigned long delta;
88375825171c7d Paul E. McKenney 2020-03-31 443 bool falsepositive;
59b73a27681c58 Paul E. McKenney 2019-01-11 444 struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
59b73a27681c58 Paul E. McKenney 2019-01-11 445 char *ticks_title;
59b73a27681c58 Paul E. McKenney 2019-01-11 446 unsigned long ticks_value;
17d9de741a1aaf Zqiang 2022-04-24 447 bool rcuc_starved;
17d9de741a1aaf Zqiang 2022-04-24 448 unsigned long j;
59b73a27681c58 Paul E. McKenney 2019-01-11 449
59b73a27681c58 Paul E. McKenney 2019-01-11 450 /*
59b73a27681c58 Paul E. McKenney 2019-01-11 451 * We could be printing a lot while holding a spinlock. Avoid
59b73a27681c58 Paul E. McKenney 2019-01-11 452 * triggering hard lockup.
59b73a27681c58 Paul E. McKenney 2019-01-11 453 */
59b73a27681c58 Paul E. McKenney 2019-01-11 454 touch_nmi_watchdog();
59b73a27681c58 Paul E. McKenney 2019-01-11 455
59b73a27681c58 Paul E. McKenney 2019-01-11 456 ticks_value = rcu_seq_ctr(rcu_state.gp_seq - rdp->gp_seq);
59b73a27681c58 Paul E. McKenney 2019-01-11 457 if (ticks_value) {
59b73a27681c58 Paul E. McKenney 2019-01-11 458 ticks_title = "GPs behind";
59b73a27681c58 Paul E. McKenney 2019-01-11 459 } else {
59b73a27681c58 Paul E. McKenney 2019-01-11 460 ticks_title = "ticks this GP";
59b73a27681c58 Paul E. McKenney 2019-01-11 461 ticks_value = rdp->ticks_this_gp;
59b73a27681c58 Paul E. McKenney 2019-01-11 462 }
59b73a27681c58 Paul E. McKenney 2019-01-11 463 delta = rcu_seq_ctr(rdp->mynode->gp_seq - rdp->rcu_iw_gp_seq);
88375825171c7d Paul E. McKenney 2020-03-31 464 falsepositive = rcu_is_gp_kthread_starving(NULL) &&
88375825171c7d Paul E. McKenney 2020-03-31 465 rcu_dynticks_in_eqs(rcu_dynticks_snap(rdp));
17d9de741a1aaf Zqiang 2022-04-24 466 rcuc_starved = rcu_is_rcuc_kthread_starving(rdp, &j);
That tree has some new returns in rcu_is_rcuc_kthread_starving() where
*jp is not set.
17d9de741a1aaf Zqiang 2022-04-24 @467 pr_err("\t%d-%c%c%c%c: (%lu %s) idle=%03x/%ld/%#lx softirq=%u/%u fqs=%ld rcuc=%ld jiffies(%s) %s\n",
59b73a27681c58 Paul E. McKenney 2019-01-11 468 cpu,
59b73a27681c58 Paul E. McKenney 2019-01-11 469 "O."[!!cpu_online(cpu)],
59b73a27681c58 Paul E. McKenney 2019-01-11 470 "o."[!!(rdp->grpmask & rdp->mynode->qsmaskinit)],
59b73a27681c58 Paul E. McKenney 2019-01-11 471 "N."[!!(rdp->grpmask & rdp->mynode->qsmaskinitnext)],
59b73a27681c58 Paul E. McKenney 2019-01-11 472 !IS_ENABLED(CONFIG_IRQ_WORK) ? '?' :
59b73a27681c58 Paul E. McKenney 2019-01-11 473 rdp->rcu_iw_pending ? (int)min(delta, 9UL) + '0' :
59b73a27681c58 Paul E. McKenney 2019-01-11 474 "!."[!delta],
59b73a27681c58 Paul E. McKenney 2019-01-11 475 ticks_value, ticks_title,
59b73a27681c58 Paul E. McKenney 2019-01-11 476 rcu_dynticks_snap(rdp) & 0xfff,
59b73a27681c58 Paul E. McKenney 2019-01-11 477 rdp->dynticks_nesting, rdp->dynticks_nmi_nesting,
59b73a27681c58 Paul E. McKenney 2019-01-11 478 rdp->softirq_snap, kstat_softirqs_cpu(RCU_SOFTIRQ, cpu),
88375825171c7d Paul E. McKenney 2020-03-31 479 data_race(rcu_state.n_force_qs) - rcu_state.n_force_qs_gpstart,
17d9de741a1aaf Zqiang 2022-04-24 480 j, rcuc_starved ? "starved" : "",
88375825171c7d Paul E. McKenney 2020-03-31 481 falsepositive ? " (false positive?)" : "");
59b73a27681c58 Paul E. McKenney 2019-01-11 482 }
--
0-DAY CI Kernel Test Service
https://01.org/lkp
prev parent reply other threads:[~2022-04-25 13:24 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-24 4:17 [PATCH v3] rcu: Dump all rcuc kthreads status for CPUs that not report quiescent state Zqiang
2022-04-24 16:06 ` Paul E. McKenney
2022-04-25 13:23 ` Dan Carpenter [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=202204241503.imwh5SqZ-lkp@intel.com \
--to=dan.carpenter@oracle.com \
--cc=frederic@kernel.org \
--cc=kbuild-all@lists.01.org \
--cc=kbuild@lists.01.org \
--cc=linux-kernel@vger.kernel.org \
--cc=lkp@intel.com \
--cc=paulmck@kernel.org \
--cc=qiang1.zhang@intel.com \
--cc=rcu@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox