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From: Joel Fernandes <joelaf@google.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Tom Zanussi <tom.zanussi@linux.intel.com>,
Namhyung Kim <namhyung@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Boqun Feng <boqun.feng@gmail.com>,
Paul McKenney <paulmck@linux.vnet.ibm.com>,
"Cc: Frederic Weisbecker" <fweisbec@gmail.com>,
Randy Dunlap <rdunlap@infradead.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Fenguang Wu <fengguang.wu@intel.com>,
Baohong Liu <baohong.liu@intel.com>,
Vedang Patel <vedang.patel@intel.com>,
"Cc: Android Kernel" <kernel-team@android.com>
Subject: Re: [PATCH] softirq: reorder trace_softirqs_on to prevent lockdep splat
Date: Mon, 30 Apr 2018 16:52:44 +0000 [thread overview]
Message-ID: <CAJWu+ooY-BXFQO+TK526pZpE6gsGRZdHq6i7yM7LSmgXi4552g@mail.gmail.com> (raw)
In-Reply-To: <20180430123813.3b8315d8@gandalf.local.home>
On Mon, Apr 30, 2018 at 9:38 AM Steven Rostedt <rostedt@goodmis.org> wrote:
> On Thu, 26 Apr 2018 21:11:00 -0700
> Joel Fernandes <joelaf@google.com> wrote:
> > I'm able to reproduce a lockdep splat when CONFIG_PROVE_LOCKING=y and
> > CONFIG_PREEMPTIRQ_EVENTS=y.
> >
> > $ echo 1 > /d/tracing/events/preemptirq/preempt_enable/enable
> > ---
> > [ 26.112609] DEBUG_LOCKS_WARN_ON(current->softirqs_enabled)
> > [ 26.112636] WARNING: CPU: 0 PID: 118 at kernel/locking/lockdep.c:3854
> > [...]
> > [ 26.144229] Call Trace:
> > [ 26.144926] <IRQ>
> > [ 26.145506] lock_acquire+0x55/0x1b0
> > [ 26.146499] ? __do_softirq+0x46f/0x4d9
> > [ 26.147571] ? __do_softirq+0x46f/0x4d9
> > [ 26.148646] trace_preempt_on+0x8f/0x240
> > [ 26.149744] ? trace_preempt_on+0x4d/0x240
> > [ 26.150862] ? __do_softirq+0x46f/0x4d9
> > [ 26.151930] preempt_count_sub+0x18a/0x1a0
> > [ 26.152985] __do_softirq+0x46f/0x4d9
> > [ 26.153937] irq_exit+0x68/0xe0
> > [ 26.154755] smp_apic_timer_interrupt+0x271/0x280
> > [ 26.156056] apic_timer_interrupt+0xf/0x20
> > [ 26.157105] </IRQ>
> I'm not able to trigger this. Is there more to it?
No that should be it. I have a 100% repro on v4.16. I will try on a newer
kernel and let you know.
thanks,
- Joel
next prev parent reply other threads:[~2018-04-30 16:52 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-27 4:11 Joel Fernandes
2018-04-30 16:38 ` Steven Rostedt
2018-04-30 16:52 ` Joel Fernandes [this message]
2018-04-30 17:01 ` Joel Fernandes
2018-04-30 22:00 ` Steven Rostedt
2018-05-01 13:49 ` Steven Rostedt
2018-06-20 20:05 ` Steven Rostedt
2018-06-20 20:20 ` Joel Fernandes
2018-05-02 1:44 Joel Fernandes
2018-05-07 18:21 ` Steven Rostedt
2018-06-01 4:52 ` Joel Fernandes
2018-06-02 17:14 ` Steven Rostedt
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