Add a test to verify that the sleepable tracing prog cannot attach to a '__x64_sys' prefix prog target.
When CONFIG_FUNCTION_ERROR_INJECTION is disabled, without the fix, the test would trigger the BUG: [ 3.460756] BUG: sleeping function called from invalid context at kernel/bpf/trampoline.c:1324 Signed-off-by: Leon Hwang <[email protected]> --- .../selftests/bpf/prog_tests/fexit_bpf2bpf.c | 57 +++++++++++++++++++ .../selftests/bpf/progs/fentry_sleepable.c | 19 +++++++ tools/testing/selftests/bpf/progs/xdp_dummy.c | 6 ++ 3 files changed, 82 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/fentry_sleepable.c diff --git a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c index 4a87d7163c8c..2523c07a16c6 100644 --- a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c +++ b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c @@ -5,6 +5,7 @@ #include <bpf/btf.h> #include "bind4_prog.skel.h" #include "freplace_progmap.skel.h" +#include "fentry_sleepable.skel.h" #include "xdp_dummy.skel.h" typedef int (*test_cb)(struct bpf_object *obj); @@ -576,6 +577,60 @@ static void test_func_replace_progmap(void) freplace_progmap__destroy(skel); } +static void test_sleepable_fentry_to_xdp(void) +{ + struct fentry_sleepable *skel = NULL; + struct xdp_dummy *skel_xdp = NULL; + int ifindex, prog_fd, err; + char buff[64] = {}; + +#ifndef __x86_64__ + test__skip(); + return; +#endif + + ifindex = if_nametoindex("lo"); + if (!ASSERT_GT(ifindex, 0, "if_nametoindex")) + return; + + skel_xdp = xdp_dummy__open_and_load(); + if (!ASSERT_OK_PTR(skel_xdp, "xdp_dummy__open_and_load")) + return; + + skel = fentry_sleepable__open(); + if (!ASSERT_OK_PTR(skel, "fentry_sleepable__open")) + goto out; + + skel->bss->user_ptr = buff; + + prog_fd = bpf_program__fd(skel_xdp->progs.__x64_sys_nop); + err = bpf_program__set_attach_target(skel->progs.fentry_xdp, prog_fd, "__x64_sys_nop"); + if (!ASSERT_OK(err, "bpf_program__set_attach_target")) + goto out; + + err = fentry_sleepable__load(skel); + ASSERT_ERR(err, "fentry_sleepable__load"); + if (err) + goto out; + + skel->links.fentry_xdp = bpf_program__attach_trace(skel->progs.fentry_xdp); + if (!ASSERT_OK_PTR(skel->links.fentry_xdp, "bpf_program__attach_trace")) + goto out; + + skel_xdp->links.__x64_sys_nop = bpf_program__attach_xdp(skel_xdp->progs.__x64_sys_nop, + ifindex); + if (!ASSERT_OK_PTR(skel_xdp->links.__x64_sys_nop, "bpf_program__attach_xdp")) + goto out; + + err = system("ping -q -c 1 -W 1 127.0.0.1 > /dev/null"); + ASSERT_OK(err, "ping"); + ASSERT_ERR(skel->bss->retval, "retval"); + +out: + fentry_sleepable__destroy(skel); + xdp_dummy__destroy(skel_xdp); +} + /* NOTE: affect other tests, must run in serial mode */ void serial_test_fexit_bpf2bpf(void) { @@ -607,4 +662,6 @@ void serial_test_fexit_bpf2bpf(void) test_func_replace_int_with_void(); if (test__start_subtest("freplace_void")) test_func_replace_void(); + if (test__start_subtest("sleepable_fentry_to_xdp")) + test_sleepable_fentry_to_xdp(); } diff --git a/tools/testing/selftests/bpf/progs/fentry_sleepable.c b/tools/testing/selftests/bpf/progs/fentry_sleepable.c new file mode 100644 index 000000000000..44b938f485e2 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/fentry_sleepable.c @@ -0,0 +1,19 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +char LICENSE[] SEC("license") = "GPL"; + +void *user_ptr; +int retval; + +SEC("fentry.s") +int BPF_PROG(fentry_xdp) +{ + char buff[64]; + + retval = bpf_copy_from_user(buff, sizeof(buff), user_ptr); + return 0; +} + diff --git a/tools/testing/selftests/bpf/progs/xdp_dummy.c b/tools/testing/selftests/bpf/progs/xdp_dummy.c index d988b2e0cee8..5f1e0771021d 100644 --- a/tools/testing/selftests/bpf/progs/xdp_dummy.c +++ b/tools/testing/selftests/bpf/progs/xdp_dummy.c @@ -10,4 +10,10 @@ int xdp_dummy_prog(struct xdp_md *ctx) return XDP_PASS; } +SEC("xdp") +int __x64_sys_nop(struct xdp_md *ctx) +{ + return XDP_PASS; +} + char _license[] SEC("license") = "GPL"; -- 2.55.0
