From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Thu, 10 Oct 2019 16:54:45 +0200
Subject: [PATCH] BPF: Disable on PREEMPT_RT
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.4/older/patches-5.4.3-rt1.tar.xz

Disable BPF on PREEMPT_RT because
- it allocates and frees memory in atomic context
- it uses up_read_non_owner()
- BPF_PROG_RUN() expects to be invoked in non-preemptible context

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 init/Kconfig    |    1 +
 net/kcm/Kconfig |    1 +
 2 files changed, 2 insertions(+)

--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1629,6 +1629,7 @@ config KALLSYMS_BASE_RELATIVE
 # syscall, maps, verifier
 config BPF_SYSCALL
 	bool "Enable bpf() system call"
+	depends on !PREEMPT_RT
 	select BPF
 	select IRQ_WORK
 	default n
--- a/net/kcm/Kconfig
+++ b/net/kcm/Kconfig
@@ -3,6 +3,7 @@
 config AF_KCM
 	tristate "KCM sockets"
 	depends on INET
+	depends on !PREEMPT_RT
 	select BPF_SYSCALL
 	select STREAM_PARSER
 	---help---