From fe83af070162399fb5c56d4e37db6adf78b6f2b0 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 24 Feb 2020 15:01:35 +0100 Subject: [PATCH] UPSTREAM: bpf/tracing: Remove redundant preempt_disable() in __bpf_trace_run() __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. Change-Id: I24a64fc030fb4609e83d68a0e121373ed4309599 Signed-off-by: Thomas Gleixner Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200224145642.847220186@linutronix.de --- kernel/trace/bpf_trace.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index c48428ebc86a..c884a071ba8b 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1923,10 +1923,9 @@ void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp) 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(); }