[PATCH 5.11 315/601] rcu: Remove spurious instrumentation_end() in rcu_nmi_enter()

Greg Kroah-Hartman
2021-05-12T17:31:00Z

From: Zhouyi Zhou <zhouzhouyi@gmail.com>

[ Upstream commit 6494ccb93271bee596a12db32ff44867d5be2321 ]

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>
Signed-off-by: Sasha Levin <sashal@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 84a3fe09630b..e7d8a0d8ea7c 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1072,7 +1072,6 @@ noinstr void rcu_nmi_enter(void)
} else if (!in_nmi()) {
instrumentation_begin();
rcu_irq_enter_check_tick();
- instrumentation_end();
} else {
instrumentation_begin();
}
--
2.30.2