From: Peter Zijlstra <peterz@infradead.org>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>, Will Deacon <will@kernel.org>,
"Paul E . McKenney" <paulmck@kernel.org>,
Joel Fernandes <joel@joelfernandes.org>,
Steven Rostedt <rostedt@goodmis.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Russell King <rmk+kernel@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Frederic Weisbecker <fweisbec@gmail.com>
Subject: Re: [PATCH 6/9] lockdep: Introduce wait-type checks
Date: Tue, 31 Mar 2020 16:55:15 +0200 [thread overview]
Message-ID: <20200331145515.GR20730@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CAMuHMdU6s1F=DnaguZXrV4sWzEO-EqTaGQ=N7zyhgGq1M+Q1Ug@mail.gmail.com>
On Tue, Mar 31, 2020 at 03:25:21PM +0200, Geert Uytterhoeven wrote:
> On arm64 (e.g. R-Car H3 ES2.0):
>
> +=============================
> +[ BUG: Invalid wait context ]
> +5.6.0-salvator-x-09423-gb29514ba13a9c459-dirty #679 Not tainted
> +-----------------------------
> +swapper/5/0 is trying to lock:
> +ffffff86ff76f398 (&pool->lock){..-.}-{3:3}, at: __queue_work+0x134/0x430
> +other info that might help us debug this:
> +1 lock held by swapper/5/0:
> + #0: ffffffc01103a4a0 (rcu_read_lock){....}-{1:3}, at:
> rcu_lock_acquire.constprop.59+0x0/0x38
> +stack backtrace:
> +CPU: 5 PID: 0 Comm: swapper/5 Not tainted
> 5.6.0-salvator-x-09423-gb29514ba13a9c459-dirty #679
> +Hardware name: Renesas Salvator-X 2nd version board based on r8a77951 (DT)
> +Call trace:
> + dump_backtrace+0x0/0x180
> + show_stack+0x14/0x1c
> + dump_stack+0xdc/0x12c
> + __lock_acquire+0x37c/0xf9c
> + lock_acquire+0x258/0x288
> + _raw_spin_lock+0x34/0x48
> + __queue_work+0x134/0x430
> + queue_work_on+0x48/0x8c
> + timers_update_nohz+0x24/0x2c
> + tick_nohz_activate.isra.15.part.16+0x5c/0x80
> + tick_setup_sched_timer+0xe0/0xf0
> + hrtimer_run_queues+0x88/0xf8
So this is complaining that it cannot take pool->lock, which is
WAIT_CONFIG while holding RCU, which presents a WAIT_CONFIG context.
This seems to implicate something is amiss, because that should be
allowed. The thing it doesn't print is the context, which in the above
case is a (hrtimer) interrupt.
I suspect this really is a hardirq context and the next patch won't cure
things. It looks nohz (full?) related.
Frederic, can you untangle this?
---
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 1511690e4de7..ac10db66cc63 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -3952,10 +3952,36 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
return ret;
}
+static inline short task_wait_context(struct task_struct *curr)
+{
+ /*
+ * Set appropriate wait type for the context; for IRQs we have to take
+ * into account force_irqthread as that is implied by PREEMPT_RT.
+ */
+ if (curr->hardirq_context) {
+ /*
+ * Check if force_irqthreads will run us threaded.
+ */
+ if (curr->hardirq_threaded || curr->irq_config)
+ return LD_WAIT_CONFIG;
+
+ return LD_WAIT_SPIN;
+ } else if (curr->softirq_context) {
+ /*
+ * Softirqs are always threaded.
+ */
+ return LD_WAIT_CONFIG;
+ }
+
+ return LD_WAIT_MAX;
+}
+
static int
print_lock_invalid_wait_context(struct task_struct *curr,
struct held_lock *hlock)
{
+ short curr_inner;
+
if (!debug_locks_off())
return 0;
if (debug_locks_silent)
@@ -3971,6 +3997,10 @@ print_lock_invalid_wait_context(struct task_struct *curr,
print_lock(hlock);
pr_warn("other info that might help us debug this:\n");
+
+ curr_inner = task_wait_context(curr);
+ pr_warn("context-{%d:%d}\n", curr_inner, curr_inner);
+
lockdep_print_held_locks(curr);
pr_warn("stack backtrace:\n");
@@ -4017,26 +4047,7 @@ static int check_wait_context(struct task_struct *curr, struct held_lock *next)
}
depth++;
- /*
- * Set appropriate wait type for the context; for IRQs we have to take
- * into account force_irqthread as that is implied by PREEMPT_RT.
- */
- if (curr->hardirq_context) {
- /*
- * Check if force_irqthreads will run us threaded.
- */
- if (curr->hardirq_threaded || curr->irq_config)
- curr_inner = LD_WAIT_CONFIG;
- else
- curr_inner = LD_WAIT_SPIN;
- } else if (curr->softirq_context) {
- /*
- * Softirqs are always threaded.
- */
- curr_inner = LD_WAIT_CONFIG;
- } else {
- curr_inner = LD_WAIT_MAX;
- }
+ curr_inner = task_wait_context(curr);
for (; depth < curr->lockdep_depth; depth++) {
struct held_lock *prev = curr->held_locks + depth;
next prev parent reply other threads:[~2020-03-31 14:56 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-13 17:46 [PATCH 0/9] Lock ordering documentation and annotation for lockdep Sebastian Andrzej Siewior
2020-03-13 17:46 ` [PATCH 1/9] Documentation: Add lock ordering and nesting documentation Sebastian Andrzej Siewior
2020-03-14 22:57 ` Randy Dunlap
2020-03-16 10:34 ` Sebastian Andrzej Siewior
2020-03-16 15:13 ` Randy Dunlap
2020-03-13 17:46 ` [PATCH 2/9] timekeeping: Split jiffies seqlock Sebastian Andrzej Siewior
2020-03-13 17:46 ` [PATCH 3/9] pci/switchtec: Don't abuse completion wait queue for poll Sebastian Andrzej Siewior
2020-03-13 18:11 ` Logan Gunthorpe
2020-03-14 0:23 ` Thomas Gleixner
2020-03-14 6:01 ` Logan Gunthorpe
2020-03-16 18:52 ` Thomas Gleixner
2020-03-16 19:24 ` Logan Gunthorpe
2020-03-16 19:34 ` Thomas Gleixner
2020-03-16 21:53 ` Logan Gunthorpe
2020-03-17 0:17 ` Thomas Gleixner
2020-03-17 1:15 ` Logan Gunthorpe
2020-03-13 19:31 ` Peter Zijlstra
2020-03-13 17:46 ` [PATCH 4/9] sched/swait: Prepare usage in completions Sebastian Andrzej Siewior
2020-03-14 0:26 ` Thomas Gleixner
2020-03-13 17:46 ` [PATCH 5/9] completion: Use simple wait queues Sebastian Andrzej Siewior
2020-03-14 15:40 ` Linus Torvalds
2020-03-16 18:55 ` Thomas Gleixner
2020-03-13 17:46 ` [PATCH 6/9] lockdep: Introduce wait-type checks Sebastian Andrzej Siewior
2020-03-31 13:25 ` Geert Uytterhoeven
2020-03-31 13:42 ` Sebastian Andrzej Siewior
2020-03-31 14:55 ` Peter Zijlstra [this message]
2020-03-31 15:28 ` Peter Zijlstra
2020-03-31 15:37 ` Frederic Weisbecker
2020-03-13 17:46 ` [PATCH 7/9] lockdep: Add hrtimer context tracing bits Sebastian Andrzej Siewior
2020-03-13 17:47 ` [PATCH 8/9] lockdep: Annotate irq_work Sebastian Andrzej Siewior
2020-03-13 17:47 ` [PATCH 9/9] lockdep: Add posixtimer context tracing bits Sebastian Andrzej Siewior
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