[tip/core/rcu,03/10] rcu: Remove spurious instrumentation_end() in rcu_nmi_enter()
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Message ID 20210304000019.22459-3-paulmck@kernel.org
State In Next
Commit a940082252b6af59b5a1cf1a5273bbcc6728b996
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Series
  • Miscellaneous fixes for v5.13
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Commit Message

Paul E. McKenney March 4, 2021, midnight UTC
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(-)

Patch
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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();
 	}