From: paulmck@kernel.org
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
mingo@kernel.org, jiangshanlai@gmail.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org,
Zhouyi Zhou <zhouzhouyi@gmail.com>,
"Paul E . McKenney" <paulmck@kernel.org>
Subject: [PATCH tip/core/rcu 03/10] rcu: Remove spurious instrumentation_end() in rcu_nmi_enter()
Date: Wed, 3 Mar 2021 16:00:12 -0800 [thread overview]
Message-ID: <20210304000019.22459-3-paulmck@kernel.org> (raw)
In-Reply-To: <20210303235958.GA22373@paulmck-ThinkPad-P72>
From: Zhouyi Zhou <zhouzhouyi@gmail.com>
In rcu_nmi_enter(), there is an erroneous instrumentation_end() in the
second branch of the "if" statement. Oddly enough, "objtool check -f
vmlinux.o" fails to complain because it is unable to correctly cover
all cases. Instead, objtool visits the third branch first, which marks
following trace_rcu_dyntick() as visited. This commit therefore removes
the spurious instrumentation_end().
Fixes: 04b25a495bd6 ("rcu: Mark rcu_nmi_enter() call to rcu_cleanup_after_idle() noinstr")
Reported-by Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/tree.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index e62c2de..4d90f20 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1076,7 +1076,6 @@ noinstr void rcu_nmi_enter(void)
} else if (!in_nmi()) {
instrumentation_begin();
rcu_irq_enter_check_tick();
- instrumentation_end();
} else {
instrumentation_begin();
}
--
2.9.5
next prev parent reply other threads:[~2021-03-04 0:14 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-03 23:59 [PATCH tip/core/rcu 0/10] Miscellaneous fixes for v5.13 Paul E. McKenney
2021-03-04 0:00 ` [PATCH tip/core/rcu 01/10] rcu: Remove superfluous rdp fetch paulmck
2021-03-04 0:00 ` [PATCH tip/core/rcu 02/10] rcu: Fix CPU-offline trace in rcutree_dying_cpu paulmck
2021-03-04 0:00 ` paulmck [this message]
2021-03-04 0:00 ` [PATCH tip/core/rcu 04/10] rculist: Replace reference to atomic_ops.rst paulmck
2021-03-04 0:00 ` [PATCH tip/core/rcu 05/10] rcu: Fix kfree_rcu() docbook errors paulmck
2021-03-04 0:00 ` [PATCH tip/core/rcu 06/10] softirq: Don't try waking ksoftirqd before it has been spawned paulmck
2021-03-12 11:36 ` Frederic Weisbecker
2021-03-15 23:11 ` Paul E. McKenney
2021-03-04 0:00 ` [PATCH tip/core/rcu 07/10] rcu: Prevent dyntick-idle until ksoftirqd " paulmck
2021-03-11 23:23 ` Frederic Weisbecker
2021-03-11 23:34 ` Paul E. McKenney
2021-03-04 0:00 ` [PATCH tip/core/rcu 08/10] docs: Correctly spell Stephen Hemminger's name paulmck
2021-03-04 0:00 ` [PATCH tip/core/rcu 09/10] rcu: Add explicit barrier() to __rcu_read_unlock() paulmck
2021-03-04 0:00 ` [PATCH tip/core/rcu 10/10] rcu/tree: Add a trace event for RCU CPU stall warnings paulmck
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