From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 24 Feb 2020 15:01:35 +0100
Subject: bpf/tracing: Remove redundant preempt_disable() in __bpf_trace_run()
Patch-mainline: v5.7-rc1
Git-commit: f03efe49bd16c017107ff5079d08ea428e390dde
References: bsc#1162702,bsc#1177028
__bpf_trace_run() disables preemption around the BPF_PROG_RUN() invocation.
This is redundant because __bpf_trace_run() is invoked from a trace point
via __DO_TRACE() which already disables preemption _before_ invoking any of
the functions which are attached to a trace point.
Remove it and add a cant_sleep() check.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200224145642.847220186@linutronix.de
Acked-by: Daniel Wagner <dwagner@suse.de>
Acked-by: Gary Lin <glin@suse.com>
---
kernel/trace/bpf_trace.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1516,10 +1516,9 @@ void bpf_put_raw_tracepoint(struct bpf_r
static __always_inline
void __bpf_trace_run(struct bpf_prog *prog, u64 *args)
{
+ cant_sleep();
rcu_read_lock();
- preempt_disable();
(void) BPF_PROG_RUN(prog, args);
- preempt_enable();
rcu_read_unlock();
}