With the introduction of kprobe.multi, it is now possible to attach
multiple kprobes to a single BPF program without the need for multiple
definitions. Additionally, this method supports wildcard-based
matching, allowing for further simplification of BPF programs. In here,
an asterisk (*) wildcard is used to map to all symbols relevant to
spin_{lock|unlock}.
Furthermore, since kprobe.multi handles symbol matching, this commit
eliminates the need for the previous logic of reading the ksym table to
verify the existence of symbols.
Signed-off-by: Daniel T. Lee <danieltimlee@xxxxxxxxx>
---
samples/bpf/spintest.bpf.c | 17 +++--------------
samples/bpf/spintest_user.c | 22 +++++++---------------
2 files changed, 10 insertions(+), 29 deletions(-)
diff --git a/samples/bpf/spintest.bpf.c b/samples/bpf/spintest.bpf.c
index 15740b16a3f7..cba5a9d50783 100644
--- a/samples/bpf/spintest.bpf.c
+++ b/samples/bpf/spintest.bpf.c
@@ -47,20 +47,9 @@ int foo(struct pt_regs *ctx) \
}
/* add kprobes to all possible *spin* functions */
-SEC("kprobe/spin_unlock")PROG(p1)
-SEC("kprobe/spin_lock")PROG(p2)
-SEC("kprobe/mutex_spin_on_owner")PROG(p3)
-SEC("kprobe/rwsem_spin_on_owner")PROG(p4)
-SEC("kprobe/spin_unlock_irqrestore")PROG(p5)
-SEC("kprobe/_raw_spin_unlock_irqrestore")PROG(p6)
-SEC("kprobe/_raw_spin_unlock_bh")PROG(p7)
-SEC("kprobe/_raw_spin_unlock")PROG(p8)
-SEC("kprobe/_raw_spin_lock_irqsave")PROG(p9)
-SEC("kprobe/_raw_spin_trylock_bh")PROG(p10)
-SEC("kprobe/_raw_spin_lock_irq")PROG(p11)
-SEC("kprobe/_raw_spin_trylock")PROG(p12)
-SEC("kprobe/_raw_spin_lock")PROG(p13)
-SEC("kprobe/_raw_spin_lock_bh")PROG(p14)
+SEC("kprobe.multi/spin_*lock*")PROG(spin_lock)
+SEC("kprobe.multi/*_spin_on_owner")PROG(spin_on_owner)
+SEC("kprobe.multi/_raw_spin_*lock*")PROG(raw_spin_lock)
/* and to inner bpf helpers */
SEC("kprobe/htab_map_update_elem")PROG(p15)
diff --git a/samples/bpf/spintest_user.c b/samples/bpf/spintest_user.c
index 8c77600776fb..55971edb1088 100644
--- a/samples/bpf/spintest_user.c
+++ b/samples/bpf/spintest_user.c
@@ -9,13 +9,12 @@
int main(int ac, char **argv)
{
- char filename[256], symbol[256];
struct bpf_object *obj = NULL;
struct bpf_link *links[20];
long key, next_key, value;
struct bpf_program *prog;
int map_fd, i, j = 0;
- const char *section;
+ char filename[256];
struct ksym *sym;
if (load_kallsyms()) {
@@ -44,20 +43,13 @@ int main(int ac, char **argv)
}
bpf_object__for_each_program(prog, obj) {
- section = bpf_program__section_name(prog);
- if (sscanf(section, "kprobe/%s", symbol) != 1)
- continue;
-
- /* Attach prog only when symbol exists */
- if (ksym_get_addr(symbol)) {
- links[j] = bpf_program__attach(prog);
- if (libbpf_get_error(links[j])) {
- fprintf(stderr, "bpf_program__attach failed\n");
- links[j] = NULL;
- goto cleanup;
- }
- j++;
+ links[j] = bpf_program__attach(prog);
+ if (libbpf_get_error(links[j])) {
+ fprintf(stderr, "bpf_program__attach failed\n");
+ links[j] = NULL;
+ goto cleanup;
}
+ j++;
}
for (i = 0; i < 5; i++) {
--
2.34.1
