diff options
| author | Yonghong Song <yonghong.song@linux.dev> | 2024-06-04 11:00:34 -0700 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2024-06-04 12:49:44 -0700 |
| commit | 898ac74c5b5f8b551a377d6a60ca4e30023ac9d2 (patch) | |
| tree | 76f7ebe742e88529d202b954570abf3b98828462 /tools/testing/selftests | |
| parent | 61ce0ea7591fef2eb6e89ce40ffcc24fda4dbbc5 (diff) | |
selftests/bpf: Ignore .llvm.<hash> suffix in kallsyms_find()
I hit the following failure when running selftests with
internal backported upstream kernel:
test_ksyms:PASS:kallsyms_fopen 0 nsec
test_ksyms:FAIL:ksym_find symbol 'bpf_link_fops' not found
#123 ksyms:FAIL
In /proc/kallsyms, we have
$ cat /proc/kallsyms | grep bpf_link_fops
ffffffff829f0cb0 d bpf_link_fops.llvm.12608678492448798416
The CONFIG_LTO_CLANG_THIN is enabled in the kernel which is responsible
for bpf_link_fops.llvm.12608678492448798416 symbol name.
In prog_tests/ksyms.c we have
kallsyms_find("bpf_link_fops", &link_fops_addr)
and kallsyms_find() compares "bpf_link_fops" with symbols
in /proc/kallsyms in order to find the entry. With
bpf_link_fops.llvm.<hash> in /proc/kallsyms, the kallsyms_find()
failed.
To fix the issue, in kallsyms_find(), if a symbol has suffix
.llvm.<hash>, that suffix will be ignored for comparison.
This fixed the test failure.
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240604180034.1356016-1-yonghong.song@linux.dev
Diffstat (limited to 'tools/testing/selftests')
| -rw-r--r-- | tools/testing/selftests/bpf/trace_helpers.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c index 70e29f316fe7..465d196c7165 100644 --- a/tools/testing/selftests/bpf/trace_helpers.c +++ b/tools/testing/selftests/bpf/trace_helpers.c @@ -211,7 +211,7 @@ long ksym_get_addr(const char *name) */ int kallsyms_find(const char *sym, unsigned long long *addr) { - char type, name[500]; + char type, name[500], *match; unsigned long long value; int err = 0; FILE *f; @@ -221,6 +221,17 @@ int kallsyms_find(const char *sym, unsigned long long *addr) return -EINVAL; while (fscanf(f, "%llx %c %499s%*[^\n]\n", &value, &type, name) > 0) { + /* If CONFIG_LTO_CLANG_THIN is enabled, static variable/function + * symbols could be promoted to global due to cross-file inlining. + * For such cases, clang compiler will add .llvm.<hash> suffix + * to those symbols to avoid potential naming conflict. + * Let us ignore .llvm.<hash> suffix during symbol comparison. + */ + if (type == 'd') { + match = strstr(name, ".llvm."); + if (match) + *match = '\0'; + } if (strcmp(name, sym) == 0) { *addr = value; goto out; |