From: Hou Tao houtao1@huawei.com
[ Upstream commit 689eb2f1ba46b4b02195ac2a71c55b96d619ebf8 ]
Using page size as max_entries when probing ring buffer map, else the probe may fail on host with 64KB page size (e.g., an ARM64 host).
After the fix, the output of "bpftool feature" on above host will be correct.
Before : eBPF map_type ringbuf is NOT available eBPF map_type user_ringbuf is NOT available
After : eBPF map_type ringbuf is available eBPF map_type user_ringbuf is available
Signed-off-by: Hou Tao houtao1@huawei.com Signed-off-by: Andrii Nakryiko andrii@kernel.org Link: https://lore.kernel.org/bpf/20221116072351.1168938-2-houtao@huaweicloud.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/lib/bpf/libbpf_probes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c index cd8c703dde71..8f425473ccaa 100644 --- a/tools/lib/bpf/libbpf_probes.c +++ b/tools/lib/bpf/libbpf_probes.c @@ -245,7 +245,7 @@ bool bpf_probe_map_type(enum bpf_map_type map_type, __u32 ifindex) case BPF_MAP_TYPE_RINGBUF: key_size = 0; value_size = 0; - max_entries = 4096; + max_entries = sysconf(_SC_PAGE_SIZE); break; case BPF_MAP_TYPE_UNSPEC: case BPF_MAP_TYPE_HASH: