This is a note to let you know that I've just added the patch titled rcu: Remove spurious instrumentation_end() in rcu_nmi_enter() to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: rcu-remove-spurious-instrumentation_end-in-rcu_nmi_e.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 9c6d2f7c3117da380dd98d8b0b11bbcfa5113d14 Author: Zhouyi Zhou <zhouzhouyi@xxxxxxxxx> Date: Mon Jan 11 09:08:59 2021 +0800 rcu: Remove spurious instrumentation_end() in rcu_nmi_enter() [ 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@xxxxxxxxxxxxxx> Signed-off-by: Zhouyi Zhou <zhouzhouyi@xxxxxxxxx> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 8a5cc76ecac9..61e250cdd7c9 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1019,7 +1019,6 @@ noinstr void rcu_nmi_enter(void) } else if (!in_nmi()) { instrumentation_begin(); rcu_irq_enter_check_tick(); - instrumentation_end(); } else { instrumentation_begin(); }