patches/0005.5-bpf-disable-preemption-for-bpf-progs-attached-to-upr.patch

From: Alexei Starovoitov <ast@kernel.org>
Date: Mon, 24 Feb 2020 11:27:15 -0800
Subject: [PATCH] bpf: disable preemption for bpf progs attached to uprobe

trace_call_bpf() no longer disables preemption on its own.
All callers of this function has to do it explicitly.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 kernel/trace/trace_uprobe.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -1333,8 +1333,15 @@ static void __uprobe_perf_func(struct tr
 	int size, esize;
 	int rctx;
 
-	if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
-		return;
+	if (bpf_prog_array_valid(call)) {
+		u32 ret;
+
+		preempt_disable();
+		ret = trace_call_bpf(call, regs);
+		preempt_enable();
+		if (!ret)
+			return;
+	}
 
 	esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));