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Subject[tip: core/rcu] rcu: Remove spurious instrumentation_end() in rcu_nmi_enter()
The following commit has been merged into the core/rcu branch of tip:

Commit-ID: 6494ccb93271bee596a12db32ff44867d5be2321
Gitweb: https://git.kernel.org/tip/6494ccb93271bee596a12db32ff44867d5be2321
Author: Zhouyi Zhou <zhouzhouyi@gmail.com>
AuthorDate: Mon, 11 Jan 2021 09:08:59 +08:00
Committer: Paul E. McKenney <paulmck@kernel.org>
CommitterDate: Mon, 08 Mar 2021 14:17:35 -08:00

rcu: Remove spurious instrumentation_end() in rcu_nmi_enter()

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();
}
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