netdev - [PATCH bpf] samples/bpf: Set rlimit for memlock to infinity in all samples

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Message-Id: <20201026233623.91728-1-toke@redhat.com>
Date:   Tue, 27 Oct 2020 00:36:23 +0100
From:   Toke Høiland-Jørgensen <toke@...hat.com>
To:     daniel@...earbox.net, ast@...com
Cc:     Toke Høiland-Jørgensen <toke@...hat.com>,
        bpf@...r.kernel.org, netdev@...r.kernel.org, brouer@...hat.com
Subject: [PATCH bpf] samples/bpf: Set rlimit for memlock to infinity in all samples

The memlock rlimit is a notorious source of failure for BPF programs. Most
of the samples just set it to infinity, but a few used a lower limit. The
problem with unconditionally setting a lower limit is that this will also
override the limit if the system-wide setting is *higher* than the limit
being set, which can lead to failures on systems that lock a lot of memory,
but set 'ulimit -l' to unlimited before running a sample.

One fix for this is to only conditionally set the limit if the current
limit is lower, but it is simpler to just unify all the samples and have
them all set the limit to infinity.

Signed-off-by: Toke Høiland-Jørgensen <toke@...hat.com>
---
 samples/bpf/task_fd_query_user.c    | 2 +-
 samples/bpf/tracex2_user.c          | 2 +-
 samples/bpf/tracex3_user.c          | 2 +-
 samples/bpf/xdp_redirect_cpu_user.c | 2 +-
 samples/bpf/xdp_rxq_info_user.c     | 2 +-
 5 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/samples/bpf/task_fd_query_user.c b/samples/bpf/task_fd_query_user.c
index 4a74531dc403..b68bd2f8fdc9 100644
--- a/samples/bpf/task_fd_query_user.c
+++ b/samples/bpf/task_fd_query_user.c
@@ -290,7 +290,7 @@ static int test_debug_fs_uprobe(char *binary_path, long offset, bool is_return)
 
 int main(int argc, char **argv)
 {
-	struct rlimit r = {1024*1024, RLIM_INFINITY};
+	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
 	extern char __executable_start;
 	char filename[256], buf[256];
 	__u64 uprobe_file_offset;
diff --git a/samples/bpf/tracex2_user.c b/samples/bpf/tracex2_user.c
index 3e36b3e4e3ef..3d6eab711d23 100644
--- a/samples/bpf/tracex2_user.c
+++ b/samples/bpf/tracex2_user.c
@@ -116,7 +116,7 @@ static void int_exit(int sig)
 
 int main(int ac, char **argv)
 {
-	struct rlimit r = {1024*1024, RLIM_INFINITY};
+	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
 	long key, next_key, value;
 	struct bpf_link *links[2];
 	struct bpf_program *prog;
diff --git a/samples/bpf/tracex3_user.c b/samples/bpf/tracex3_user.c
index 70e987775c15..83e0fecbb01a 100644
--- a/samples/bpf/tracex3_user.c
+++ b/samples/bpf/tracex3_user.c
@@ -107,7 +107,7 @@ static void print_hist(int fd)
 
 int main(int ac, char **argv)
 {
-	struct rlimit r = {1024*1024, RLIM_INFINITY};
+	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
 	struct bpf_link *links[2];
 	struct bpf_program *prog;
 	struct bpf_object *obj;
diff --git a/samples/bpf/xdp_redirect_cpu_user.c b/samples/bpf/xdp_redirect_cpu_user.c
index 6fb8dbde62c5..f78cb18319aa 100644
--- a/samples/bpf/xdp_redirect_cpu_user.c
+++ b/samples/bpf/xdp_redirect_cpu_user.c
@@ -765,7 +765,7 @@ static int load_cpumap_prog(char *file_name, char *prog_name,
 
 int main(int argc, char **argv)
 {
-	struct rlimit r = {10 * 1024 * 1024, RLIM_INFINITY};
+	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
 	char *prog_name = "xdp_cpu_map5_lb_hash_ip_pairs";
 	char *mprog_filename = "xdp_redirect_kern.o";
 	char *redir_interface = NULL, *redir_map = NULL;
diff --git a/samples/bpf/xdp_rxq_info_user.c b/samples/bpf/xdp_rxq_info_user.c
index caa4e7ffcfc7..93fa1bc54f13 100644
--- a/samples/bpf/xdp_rxq_info_user.c
+++ b/samples/bpf/xdp_rxq_info_user.c
@@ -450,7 +450,7 @@ static void stats_poll(int interval, int action, __u32 cfg_opt)
 int main(int argc, char **argv)
 {
 	__u32 cfg_options= NO_TOUCH ; /* Default: Don't touch packet memory */
-	struct rlimit r = {10 * 1024 * 1024, RLIM_INFINITY};
+	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
 	struct bpf_prog_load_attr prog_load_attr = {
 		.prog_type	= BPF_PROG_TYPE_XDP,
 	};
-- 
2.29.0