9a5f25ad30
Make sample_cnt volatile to fix possible selftests failure due to compiler
optimization preventing latest sample_cnt value to be visible to main thread.
sample_cnt is incremented in background thread, which is then joined into main
thread. So in terms of visibility sample_cnt update is ok. But because it's
not volatile, compiler might make optimizations that would prevent main thread
to see latest updated value. Fix this by marking global variable volatile.
Fixes:
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| .. | ||
| benchs | ||
| gnu | ||
| map_tests | ||
| prog_tests | ||
| progs | ||
| verifier | ||
| .gitignore | ||
| bench.c | ||
| bench.h | ||
| bpf_legacy.h | ||
| bpf_rand.h | ||
| bpf_rlimit.h | ||
| bpf_tcp_helpers.h | ||
| bpf_util.h | ||
| cgroup_helpers.c | ||
| cgroup_helpers.h | ||
| config | ||
| flow_dissector_load.c | ||
| flow_dissector_load.h | ||
| get_cgroup_id_user.c | ||
| Makefile | ||
| netcnt_common.h | ||
| network_helpers.c | ||
| network_helpers.h | ||
| README.rst | ||
| tcp_client.py | ||
| tcp_server.py | ||
| test_bpftool_build.sh | ||
| test_bpftool.py | ||
| test_bpftool.sh | ||
| test_btf.c | ||
| test_btf.h | ||
| test_cgroup_storage.c | ||
| test_cpp.cpp | ||
| test_current_pid_tgid_new_ns.c | ||
| test_dev_cgroup.c | ||
| test_flow_dissector.c | ||
| test_flow_dissector.sh | ||
| test_ftrace.sh | ||
| test_iptunnel_common.h | ||
| test_kmod.sh | ||
| test_lirc_mode2_user.c | ||
| test_lirc_mode2.sh | ||
| test_lpm_map.c | ||
| test_lru_map.c | ||
| test_lwt_ip_encap.sh | ||
| test_lwt_seg6local.sh | ||
| test_maps.c | ||
| test_maps.h | ||
| test_netcnt.c | ||
| test_offload.py | ||
| test_progs.c | ||
| test_progs.h | ||
| test_select_reuseport_common.h | ||
| test_skb_cgroup_id_user.c | ||
| test_skb_cgroup_id.sh | ||
| test_sock_addr.c | ||
| test_sock_addr.sh | ||
| test_sock_fields.c | ||
| test_sock.c | ||
| test_socket_cookie.c | ||
| test_sockmap.c | ||
| test_stub.c | ||
| test_sysctl.c | ||
| test_tag.c | ||
| test_tc_edt.sh | ||
| test_tc_tunnel.sh | ||
| test_tcp_check_syncookie_user.c | ||
| test_tcp_check_syncookie.sh | ||
| test_tcpbpf_user.c | ||
| test_tcpbpf.h | ||
| test_tcpnotify_user.c | ||
| test_tcpnotify.h | ||
| test_tunnel.sh | ||
| test_verifier_log.c | ||
| test_verifier.c | ||
| test_xdp_meta.sh | ||
| test_xdp_redirect.sh | ||
| test_xdp_veth.sh | ||
| test_xdp_vlan_mode_generic.sh | ||
| test_xdp_vlan_mode_native.sh | ||
| test_xdp_vlan.sh | ||
| test_xdping.sh | ||
| testing_helpers.c | ||
| testing_helpers.h | ||
| trace_helpers.c | ||
| trace_helpers.h | ||
| urandom_read.c | ||
| with_addr.sh | ||
| with_tunnels.sh | ||
| xdping.c | ||
| xdping.h | ||
================== BPF Selftest Notes ================== General instructions on running selftests can be found in `Documentation/bpf/bpf_devel_QA.rst`_. Additional information about selftest failures are documented here. bpf_iter test failures with clang/llvm 10.0.0 ============================================= With clang/llvm 10.0.0, the following two bpf_iter tests failed: * ``bpf_iter/ipv6_route`` * ``bpf_iter/netlink`` The symptom for ``bpf_iter/ipv6_route`` looks like .. code-block:: c 2: (79) r8 = *(u64 *)(r1 +8) ... 14: (bf) r2 = r8 15: (0f) r2 += r1 ; BPF_SEQ_PRINTF(seq, "%pi6 %02x ", &rt->fib6_dst.addr, rt->fib6_dst.plen); 16: (7b) *(u64 *)(r8 +64) = r2 only read is supported The symptom for ``bpf_iter/netlink`` looks like .. code-block:: c ; struct netlink_sock *nlk = ctx->sk; 2: (79) r7 = *(u64 *)(r1 +8) ... 15: (bf) r2 = r7 16: (0f) r2 += r1 ; BPF_SEQ_PRINTF(seq, "%pK %-3d ", s, s->sk_protocol); 17: (7b) *(u64 *)(r7 +0) = r2 only read is supported This is due to a llvm BPF backend bug. The fix https://reviews.llvm.org/D78466 has been pushed to llvm 10.x release branch and will be available in 10.0.1. The fix is available in llvm 11.0.0 trunk.