diff options
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/lib/bpf/bpf_helpers.h | 5 | ||||
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 6 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/progs/task_kfunc_success.c | 20 |
3 files changed, 30 insertions, 1 deletions
diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h index 7d12d3e620cc..e7e1a8acc299 100644 --- a/tools/lib/bpf/bpf_helpers.h +++ b/tools/lib/bpf/bpf_helpers.h @@ -177,6 +177,11 @@ enum libbpf_tristate { #define __kptr_untrusted __attribute__((btf_type_tag("kptr_untrusted"))) #define __kptr __attribute__((btf_type_tag("kptr"))) +#define bpf_ksym_exists(sym) ({ \ + _Static_assert(!__builtin_constant_p(!!sym), #sym " should be marked as __weak"); \ + !!sym; \ +}) + #ifndef ___bpf_concat #define ___bpf_concat(a, b) a ## b #endif diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index a557718401e4..4c34fbd7b5be 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -7533,6 +7533,12 @@ static int bpf_object__resolve_ksym_func_btf_id(struct bpf_object *obj, ext->is_set = true; ext->ksym.kernel_btf_id = kfunc_id; ext->ksym.btf_fd_idx = mod_btf ? mod_btf->fd_array_idx : 0; + /* Also set kernel_btf_obj_fd to make sure that bpf_object__relocate_data() + * populates FD into ld_imm64 insn when it's used to point to kfunc. + * {kernel_btf_id, btf_fd_idx} -> fixup bpf_call. + * {kernel_btf_id, kernel_btf_obj_fd} -> fixup ld_imm64. + */ + ext->ksym.kernel_btf_obj_fd = mod_btf ? mod_btf->fd : 0; pr_debug("extern (func ksym) '%s': resolved to kernel [%d]\n", ext->name, kfunc_id); diff --git a/tools/testing/selftests/bpf/progs/task_kfunc_success.c b/tools/testing/selftests/bpf/progs/task_kfunc_success.c index 4f61596b0242..cfa7f12b84e8 100644 --- a/tools/testing/selftests/bpf/progs/task_kfunc_success.c +++ b/tools/testing/selftests/bpf/progs/task_kfunc_success.c @@ -17,6 +17,10 @@ int err, pid; * TP_PROTO(struct task_struct *p, u64 clone_flags) */ +struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym __weak; +void invalid_kfunc(void) __ksym __weak; +void bpf_testmod_test_mod_kfunc(int i) __ksym __weak; + static bool is_test_kfunc_task(void) { int cur_pid = bpf_get_current_pid_tgid() >> 32; @@ -26,7 +30,21 @@ static bool is_test_kfunc_task(void) static int test_acquire_release(struct task_struct *task) { - struct task_struct *acquired; + struct task_struct *acquired = NULL; + + if (!bpf_ksym_exists(bpf_task_acquire)) { + err = 3; + return 0; + } + if (!bpf_ksym_exists(bpf_testmod_test_mod_kfunc)) { + err = 4; + return 0; + } + if (bpf_ksym_exists(invalid_kfunc)) { + /* the verifier's dead code elimination should remove this */ + err = 5; + asm volatile ("goto -1"); /* for (;;); */ + } acquired = bpf_task_acquire(task); bpf_task_release(acquired); |