From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 24 Feb 2020 15:01:38 +0100
Subject: perf/bpf: Remove preempt disable around BPF invocation
Patch-mainline: v5.7-rc1
Git-commit: 1d7bf6b7d3e8353c3fac648f3f9b3010458570c2
References: bsc#1162702,bsc#1177028

The BPF invocation from the perf event overflow handler does not require to
disable preemption because this is called from NMI or at least hard
interrupt context which is already non-preemptible.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200224145643.151953573@linutronix.de
Acked-by: Daniel Wagner <dwagner@suse.de>
Acked-by: Gary Lin <glin@suse.com>
---
 kernel/events/core.c |    2 --
 1 file changed, 2 deletions(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -8994,7 +8994,6 @@ static void bpf_overflow_handler(struct
 	int ret = 0;
 
 	ctx.regs = perf_arch_bpf_user_pt_regs(regs);
-	preempt_disable();
 	if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
 		goto out;
 	rcu_read_lock();
@@ -9002,7 +9001,6 @@ static void bpf_overflow_handler(struct
 	rcu_read_unlock();
 out:
 	__this_cpu_dec(bpf_prog_active);
-	preempt_enable();
 	if (!ret)
 		return;