From: Jackie Liu <liuyun01@xxxxxxxxxx>
When using regular expression matching with "kprobe multi", it scans all
the functions under "/proc/kallsyms" that can be matched. However, not all
of them can be traced by kprobe.multi. If any one of the functions fails
to be traced, it will result in the failure of all functions. The best
approach is to filter out the functions that cannot be traced to ensure
proper tracking of the functions.
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-kbuild-all/202307030355.TdXOHklM-lkp@xxxxxxxxx/
Suggested-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Suggested-by: Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx>
Signed-off-by: Jackie Liu <liuyun01@xxxxxxxxxx>
---
v2->v3: fix 'fscanf' may overflow
tools/lib/bpf/libbpf.c | 122 ++++++++++++++++++++++++++++++++++++-----
1 file changed, 109 insertions(+), 13 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 214f828ece6b..232268215bb7 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -10224,6 +10224,12 @@ static const char *tracefs_uprobe_events(void)
return use_debugfs() ? DEBUGFS"/uprobe_events" : TRACEFS"/uprobe_events";
}
+static const char *tracefs_available_filter_functions(void)
+{
+ return use_debugfs() ? DEBUGFS"/available_filter_functions" :
+ TRACEFS"/available_filter_functions";
+}
+
static void gen_kprobe_legacy_event_name(char *buf, size_t buf_sz,
const char *kfunc_name, size_t offset)
{
@@ -10539,23 +10545,113 @@ struct kprobe_multi_resolve {
size_t cnt;
};
-static int
-resolve_kprobe_multi_cb(unsigned long long sym_addr, char sym_type,
- const char *sym_name, void *ctx)
+static int qsort_compare_function(const void *a, const void *b)
{
- struct kprobe_multi_resolve *res = ctx;
- int err;
+ return strcmp(*(const char **)a, *(const char **)b);
+}
- if (!glob_match(sym_name, res->pattern))
- return 0;
+static int bsearch_compare_function(const void *a, const void *b)
+{
+ return strcmp((const char *)a, *(const char **)b);
+}
- err = libbpf_ensure_mem((void **) &res->addrs, &res->cap, sizeof(unsigned long),
- res->cnt + 1);
- if (err)
+static int libbpf_available_kallsyms_parse(struct kprobe_multi_resolve *res)
+{
+ char sym_name[500];
+ const char *available_functions_file = tracefs_available_filter_functions();
+ FILE *f;
+ int err = 0, ret, i;
+ struct function_info {
+ const char **syms;
+ size_t cap;
+ size_t cnt;
+ } infos = {};
+
+ f = fopen(available_functions_file, "r");
+ if (!f) {
+ err = -errno;
+ pr_warn("failed to open %s\n", available_functions_file);
return err;
+ }
- res->addrs[res->cnt++] = (unsigned long) sym_addr;
- return 0;
+ while (true) {
+ char *name;
+
+ ret = fscanf(f, "%499s%*[^\n]\n", sym_name);
+ if (ret == EOF && feof(f))
+ break;
+
