From f6827526279d75f0b1c1605b1bf560024bd7696f Mon Sep 17 00:00:00 2001 From: Ivan Vecera Date: Fri, 15 Mar 2019 21:04:14 +0100 Subject: [PATCH] selftests: bpf: modify urandom_read and link it non-statically After some experiences I found that urandom_read does not need to be linked statically. When the 'read' syscall call is moved to separate non-inlined function then bpf_get_stackid() is able to find the executable in stack trace and extract its build_id from it. Signed-off-by: Ivan Vecera Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/Makefile | 2 +- tools/testing/selftests/bpf/urandom_read.c | 15 +++++++++++---- 2 files changed, 12 insertions(+), 5 deletions(-) diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 25d3939eb840..edd59707cb1f 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -70,7 +70,7 @@ TEST_CUSTOM_PROGS = $(OUTPUT)/urandom_read all: $(TEST_CUSTOM_PROGS) $(OUTPUT)/urandom_read: $(OUTPUT)/%: %.c - $(CC) -o $@ -static $< -Wl,--build-id + $(CC) -o $@ $< -Wl,--build-id BPFOBJ := $(OUTPUT)/libbpf.a diff --git a/tools/testing/selftests/bpf/urandom_read.c b/tools/testing/selftests/bpf/urandom_read.c index 9de8b7cb4e6d..db781052758d 100644 --- a/tools/testing/selftests/bpf/urandom_read.c +++ b/tools/testing/selftests/bpf/urandom_read.c @@ -7,11 +7,19 @@ #define BUF_SIZE 256 +static __attribute__((noinline)) +void urandom_read(int fd, int count) +{ + char buf[BUF_SIZE]; + int i; + + for (i = 0; i < count; ++i) + read(fd, buf, BUF_SIZE); +} + int main(int argc, char *argv[]) { int fd = open("/dev/urandom", O_RDONLY); - int i; - char buf[BUF_SIZE]; int count = 4; if (fd < 0) @@ -20,8 +28,7 @@ int main(int argc, char *argv[]) if (argc == 2) count = atoi(argv[1]); - for (i = 0; i < count; ++i) - read(fd, buf, BUF_SIZE); + urandom_read(fd, count); close(fd); return 0;