diff mbox series

[v2,bpf-next,4/4] selftests/bpf: Add test for bpf_ksym_exists().

Message ID 20230317201920.62030-5-alexei.starovoitov@gmail.com (mailing list archive)
State Accepted
Commit 95fdf6e313a981b0729886f86916190cb418b04c
Delegated to: BPF
Headers show
Series bpf: Add detection of kfuncs. | expand

Checks

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bpf/vmtest-bpf-next-VM_Test-32 success Logs for test_verifier on aarch64 with gcc
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bpf/vmtest-bpf-next-VM_Test-34 success Logs for test_verifier on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-35 success Logs for test_verifier on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-36 success Logs for test_verifier on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-21 success Logs for test_progs_no_alu32 on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-16 success Logs for test_progs on s390x with gcc
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 20 this patch: 20
netdev/cc_maintainers warning 11 maintainers not CCed: linux-kselftest@vger.kernel.org mykolal@fb.com song@kernel.org shuah@kernel.org sdf@google.com haoluo@google.com yhs@fb.com john.fastabend@gmail.com kpsingh@kernel.org jolsa@kernel.org martin.lau@linux.dev
netdev/build_clang success Errors and warnings before: 18 this patch: 18
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 20 this patch: 20
netdev/checkpatch warning CHECK: No space is necessary after a cast
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next-VM_Test-11 success Logs for test_maps on s390x with gcc
bpf/vmtest-bpf-next-PR success PR summary

Commit Message

Alexei Starovoitov March 17, 2023, 8:19 p.m. UTC 
From: Alexei Starovoitov <ast@kernel.org>

Add load and run time test for bpf_ksym_exists() and check that the verifier
performs dead code elimination for non-existing kfunc.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
---
 .../selftests/bpf/progs/task_kfunc_success.c  | 20 ++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)
diff mbox series

Patch

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);