bpf: test_bpf: turn off preemption in function __run_once

roxell · borkmann · commit fd92d6648feb · 2019-02-25T22:18:07.000+01:00
When running BPF test suite the following splat occurs: [ 415.930950] test_bpf: #0 TAX jited:0 [ 415.931067] BUG: assuming atomic context at lib/test_bpf.c:6674 [ 415.946169] in_atomic(): 0, irqs_disabled(): 0, pid: 11556, name: modprobe [ 415.953176] INFO: lockdep is turned off. [ 415.957207] CPU: 1 PID: 11556 Comm: modprobe Tainted: G W 5.0.0-rc7-next-20190220 #1 [ 415.966328] Hardware name: HiKey Development Board (DT) [ 415.971592] Call trace: [ 415.974069] dump_backtrace+0x0/0x160 [ 415.977761] show_stack+0x24/0x30 [ 415.981104] dump_stack+0xc8/0x114 [ 415.984534] __cant_sleep+0xf0/0x108 [ 415.988145] test_bpf_init+0x5e0/0x1000 [test_bpf] [ 415.992971] do_one_initcall+0x90/0x428 [ 415.996837] do_init_module+0x60/0x1e4 [ 416.000614] load_module+0x1de0/0x1f50 [ 416.004391] __se_sys_finit_module+0xc8/0xe0 [ 416.008691] __arm64_sys_finit_module+0x24/0x30 [ 416.013255] el0_svc_common+0x78/0x130 [ 416.017031] el0_svc_handler+0x38/0x78 [ 416.020806] el0_svc+0x8/0xc Rework so that preemption is disabled when we loop over function 'BPF_PROG_RUN(...)'. Fixes: 568f196 ("bpf: check that BPF programs run with preemption disabled") Suggested-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Anders Roxell <anders.roxell@linaro.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
diff --git a/lib/test_bpf.c b/lib/test_bpf.c
@@ -6668,12 +6668,14 @@ static int __run_one(const struct bpf_prog *fp, const void *data,
 	u64 start, finish;
 	int ret = 0, i;
 
+	preempt_disable();
 	start = ktime_get_ns();
 
 	for (i = 0; i < runs; i++)
 		ret = BPF_PROG_RUN(fp, data);
 
 	finish = ktime_get_ns();
+	preempt_enable();
 
 	*duration = finish - start;
 	do_div(*duration, runs);
