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Commit 740f8a65 authored by Stanislav Fomichev's avatar Stanislav Fomichev Committed by Daniel Borkmann
Browse files

selftests/bpf: make sure signal interrupts BPF_PROG_TEST_RUN 



Simple test that I used to reproduce the issue in the previous commit:
Do BPF_PROG_TEST_RUN with max iterations, each program is 4096 simple
move instructions. File alarm in 0.1 second and check that
bpf_prog_test_run is interrupted (i.e. test doesn't hang).

Note: reposting this for bpf-next to avoid linux-next conflict. In this
version I test both BPF_PROG_TYPE_SOCKET_FILTER (which uses generic
bpf_test_run implementation) and BPF_PROG_TYPE_FLOW_DISSECTOR (which has
it own loop with preempt handling in bpf_prog_test_run_flow_dissector).

Signed-off-by: default avatarStanislav Fomichev <sdf@google.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent a439184d

tools/testing/selftests/bpf/test_progs.c

+44 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <stdlib.h>

#include <stdarg.h>

#include <time.h>

#include <signal.h>



#include <linux/types.h>

typedef __u16 __sum16;
@@ -28,6 +29,7 @@ typedef __u16 __sum16; 
#include <sys/ioctl.h>

#include <sys/wait.h>

#include <sys/types.h>

#include <sys/time.h>

#include <fcntl.h>

#include <pthread.h>

#include <linux/bpf.h>
@@ -2108,6 +2110,46 @@ static void test_map_lock(void) 
	bpf_object__close(obj);

}



static void sigalrm_handler(int s) {}

static struct sigaction sigalrm_action = {

	.sa_handler = sigalrm_handler,

};



static void test_signal_pending(enum bpf_prog_type prog_type)

{

	struct bpf_insn prog[4096];

	struct itimerval timeo = {

		.it_value.tv_usec = 100000, /* 100ms */

	};

	__u32 duration, retval;

	int prog_fd;

	int err;

	int i;



	for (i = 0; i < ARRAY_SIZE(prog); i++)

		prog[i] = BPF_ALU64_IMM(BPF_MOV, BPF_REG_0, 0);

	prog[ARRAY_SIZE(prog) - 1] = BPF_EXIT_INSN();



	prog_fd = bpf_load_program(prog_type, prog, ARRAY_SIZE(prog),

				   "GPL", 0, NULL, 0);

	CHECK(prog_fd < 0, "test-run", "errno %d\n", errno);



	err = sigaction(SIGALRM, &sigalrm_action, NULL);

	CHECK(err, "test-run-signal-sigaction", "errno %d\n", errno);



	err = setitimer(ITIMER_REAL, &timeo, NULL);

	CHECK(err, "test-run-signal-timer", "errno %d\n", errno);



	err = bpf_prog_test_run(prog_fd, 0xffffffff, &pkt_v4, sizeof(pkt_v4),

				NULL, NULL, &retval, &duration);

	CHECK(duration > 500000000, /* 500ms */

	      "test-run-signal-duration",

	      "duration %dns > 500ms\n",

	      duration);



	signal(SIGALRM, SIG_DFL);

}



int main(void)

{

	srand(time(NULL));
@@ -2138,6 +2180,8 @@ int main(void) 
	test_flow_dissector();

	test_spinlock();

	test_map_lock();

	test_signal_pending(BPF_PROG_TYPE_SOCKET_FILTER);

	test_signal_pending(BPF_PROG_TYPE_FLOW_DISSECTOR);



	printf("Summary: %d PASSED, %d FAILED\n", pass_cnt, error_cnt);

	return error_cnt ? EXIT_FAILURE : EXIT_SUCCESS;