[PATCH bpf-next v2 5/8] samples: bpf: Extend RLIMIT_MEMLOCK for xdp_{sample_pkts, router_ipv4}

[Maciej Fijalkowski]

There is a common problem with xdp samples that happens when user wants
to run a particular sample and some bpf program is already loaded. The
default 64kb RLIMIT_MEMLOCK resource limit will cause a following error
(assuming that xdp sample that is failing was converted to libbpf
usage):

libbpf: Error in bpf_object__probe_name():Operation not permitted(1).
Couldn't load basic 'r0 = 0' BPF program.
libbpf: failed to load object './xdp_sample_pkts_kern.o'

Fix it in xdp_sample_pkts and xdp_router_ipv4 by setting RLIMIT_MEMLOCK
to RLIM_INFINITY.

Signed-off-by: Maciej Fijalkowski <maciejromanfijalkow...@gmail.com>
Reviewed-by: Jakub Kicinski <jakub.kicin...@netronome.com>
---
 samples/bpf/xdp_router_ipv4_user.c | 7 +++++++
 samples/bpf/xdp_sample_pkts_user.c | 7 +++++++
 2 files changed, 14 insertions(+)

diff --git a/samples/bpf/xdp_router_ipv4_user.c 
b/samples/bpf/xdp_router_ipv4_user.c
index cea2306f5ab7..c63c6beec7d6 100644
--- a/samples/bpf/xdp_router_ipv4_user.c
+++ b/samples/bpf/xdp_router_ipv4_user.c
@@ -25,6 +25,7 @@
 #include <sys/syscall.h>
 #include "bpf_util.h"
 #include "bpf/libbpf.h"
+#include <sys/resource.h>
 
 int sock, sock_arp, flags = 0;
 static int total_ifindex;
@@ -609,6 +610,7 @@ static int monitor_route(void)
 
 int main(int ac, char **argv)
 {
+       struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
        struct bpf_prog_load_attr prog_load_attr = {
                .prog_type      = BPF_PROG_TYPE_XDP,
        };
@@ -635,6 +637,11 @@ int main(int ac, char **argv)
                ifname_list = (argv + 1);
        }
 
+       if (setrlimit(RLIMIT_MEMLOCK, &r)) {
+               perror("setrlimit(RLIMIT_MEMLOCK)");
+               return 1;
+       }
+
        if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
                return 1;
 
diff --git a/samples/bpf/xdp_sample_pkts_user.c 
b/samples/bpf/xdp_sample_pkts_user.c
index 8dd87c1eb560..5f5828ee0761 100644
--- a/samples/bpf/xdp_sample_pkts_user.c
+++ b/samples/bpf/xdp_sample_pkts_user.c
@@ -12,6 +12,7 @@
 #include <signal.h>
 #include <libbpf.h>
 #include <bpf/bpf.h>
+#include <sys/resource.h>
 
 #include "perf-sys.h"
 #include "trace_helpers.h"
@@ -99,6 +100,7 @@ static void sig_handler(int signo)
 
 int main(int argc, char **argv)
 {
+       struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
        struct bpf_prog_load_attr prog_load_attr = {
                .prog_type      = BPF_PROG_TYPE_XDP,
        };
@@ -114,6 +116,11 @@ int main(int argc, char **argv)
                return 1;
        }
 
+       if (setrlimit(RLIMIT_MEMLOCK, &r)) {
+               perror("setrlimit(RLIMIT_MEMLOCK)");
+               return 1;
+       }
+
        numcpus = get_nprocs();
        if (numcpus > MAX_CPUS)
                numcpus = MAX_CPUS;
-- 
2.16.1