From 2eb7648558a7911f2208e8940cd22ca40e93cc76 Mon Sep 17 00:00:00 2001 From: Jerome Marchand Date: Thu, 19 Jun 2025 16:06:02 +0200 Subject: [PATCH 1/2] bpf: Specify access type of bpf_sysctl_get_name args The second argument of bpf_sysctl_get_name() helper is a pointer to a buffer that is being written to. However that isn't specify in the prototype. Until commit 37cce22dbd51a ("bpf: verifier: Refactor helper access type tracking"), all helper accesses were considered as a possible write access by the verifier, so no big harm was done. However, since then, the verifier might make wrong asssumption about the content of that address which might lead it to make faulty optimizations (such as removing code that was wrongly labeled dead). This is what happens in test_sysctl selftest to the tests related to sysctl_get_name. Add MEM_WRITE flag the second argument of bpf_sysctl_get_name(). Signed-off-by: Jerome Marchand Acked-by: Yonghong Song Link: https://lore.kernel.org/r/20250619140603.148942-2-jmarchan@redhat.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/cgroup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index 9122c39870bf..f4885514f007 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -2134,7 +2134,7 @@ static const struct bpf_func_proto bpf_sysctl_get_name_proto = { .gpl_only = false, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_CTX, - .arg2_type = ARG_PTR_TO_MEM, + .arg2_type = ARG_PTR_TO_MEM | MEM_WRITE, .arg3_type = ARG_CONST_SIZE, .arg4_type = ARG_ANYTHING, }; From b8a205486ed5c0c5c0386e472157a81ce686af25 Mon Sep 17 00:00:00 2001 From: Jerome Marchand Date: Thu, 19 Jun 2025 16:06:03 +0200 Subject: [PATCH 2/2] selftests/bpf: Convert test_sysctl to prog_tests Convert test_sysctl test to prog_tests with minimal change to the tests themselves. Signed-off-by: Jerome Marchand Acked-by: Yonghong Song Link: https://lore.kernel.org/r/20250619140603.148942-3-jmarchan@redhat.com Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/.gitignore | 1 - tools/testing/selftests/bpf/Makefile | 5 +-- .../bpf/{ => prog_tests}/test_sysctl.c | 37 ++++--------------- 3 files changed, 10 insertions(+), 33 deletions(-) rename tools/testing/selftests/bpf/{ => prog_tests}/test_sysctl.c (98%) diff --git a/tools/testing/selftests/bpf/.gitignore b/tools/testing/selftests/bpf/.gitignore index e2a2c46c008b..3d8378972d26 100644 --- a/tools/testing/selftests/bpf/.gitignore +++ b/tools/testing/selftests/bpf/.gitignore @@ -21,7 +21,6 @@ test_lirc_mode2_user flow_dissector_load test_tcpnotify_user test_libbpf -test_sysctl xdping test_cpp *.d diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index cf5ed3bee573..910d8d6402ef 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -73,7 +73,7 @@ endif # Order correspond to 'make run_tests' order TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_progs \ test_sockmap \ - test_tcpnotify_user test_sysctl \ + test_tcpnotify_user \ test_progs-no_alu32 TEST_INST_SUBDIRS := no_alu32 @@ -220,7 +220,7 @@ ifeq ($(VMLINUX_BTF),) $(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)") endif -# Define simple and short `make test_progs`, `make test_sysctl`, etc targets +# Define simple and short `make test_progs`, `make test_maps`, etc targets # to build individual tests. # NOTE: Semicolon at the end is critical to override lib.mk's default static # rule for binaries. @@ -329,7 +329,6 @@ NETWORK_HELPERS := $(OUTPUT)/network_helpers.o $(OUTPUT)/test_sockmap: $(CGROUP_HELPERS) $(TESTING_HELPERS) $(OUTPUT)/test_tcpnotify_user: $(CGROUP_HELPERS) $(TESTING_HELPERS) $(TRACE_HELPERS) $(OUTPUT)/test_sock_fields: $(CGROUP_HELPERS) $(TESTING_HELPERS) -$(OUTPUT)/test_sysctl: $(CGROUP_HELPERS) $(TESTING_HELPERS) $(OUTPUT)/test_tag: $(TESTING_HELPERS) $(OUTPUT)/test_lirc_mode2_user: $(TESTING_HELPERS) $(OUTPUT)/xdping: $(TESTING_HELPERS) diff --git a/tools/testing/selftests/bpf/test_sysctl.c b/tools/testing/selftests/bpf/prog_tests/test_sysctl.c similarity index 98% rename from tools/testing/selftests/bpf/test_sysctl.c rename to tools/testing/selftests/bpf/prog_tests/test_sysctl.c index bcdbd27f22f0..273dd41ca09e 100644 --- a/tools/testing/selftests/bpf/test_sysctl.c +++ b/tools/testing/selftests/bpf/prog_tests/test_sysctl.c @@ -1,22 +1,8 @@ // SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2019 Facebook -#include -#include -#include -#include -#include -#include - -#include - -#include -#include - -#include -#include "bpf_util.h" +#include "test_progs.h" #include "cgroup_helpers.h" -#include "testing_helpers.h" #define CG_PATH "/foo" #define MAX_INSNS 512 @@ -1608,26 +1594,19 @@ static int run_tests(int cgfd) return fails ? -1 : 0; } -int main(int argc, char **argv) +void test_sysctl(void) { - int cgfd = -1; - int err = 0; + int cgfd; cgfd = cgroup_setup_and_join(CG_PATH); - if (cgfd < 0) - goto err; + if (!ASSERT_OK_FD(cgfd < 0, "create_cgroup")) + goto out; - /* Use libbpf 1.0 API mode */ - libbpf_set_strict_mode(LIBBPF_STRICT_ALL); + if (!ASSERT_OK(run_tests(cgfd), "run_tests")) + goto out; - if (run_tests(cgfd)) - goto err; - - goto out; -err: - err = -1; out: close(cgfd); cleanup_cgroup_environment(); - return err; + return; }