On 13/01/2023 09:34, menglong8.dong@xxxxxxxxx wrote:
> From: Menglong Dong <imagedong@xxxxxxxxxxx>
>
> '.' is not allowed in the event name of kprobe. Therefore, we will get a
> EINVAL if the kernel function name has a '.' in legacy kprobe attach
> case, such as 'icmp_reply.constprop.0'.
>
> In order to adapt this case, we need to replace the '.' with other char
> in gen_kprobe_legacy_event_name(). And I use '_' for this propose.
>
> Signed-off-by: Menglong Dong <imagedong@xxxxxxxxxxx>
> ---
> tools/lib/bpf/libbpf.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index fdfb1ca34ced..5d6f6675c2f2 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -9994,9 +9994,16 @@ static void gen_kprobe_legacy_event_name(char *buf, size_t buf_sz,
> const char *kfunc_name, size_t offset)
> {
> static int index = 0;
> + int i = 0;
>
> snprintf(buf, buf_sz, "libbpf_%u_%s_0x%zx_%d", getpid(), kfunc_name, offset,
> __sync_fetch_and_add(&index, 1));
> +
> + while (buf[i] != '\0') {
> + if (buf[i] == '.')
> + buf[i] = '_';
> + i++;
> + }
> }
probably more naturally expressed as a for() loop as is done in
gen_uprobe_legacy_event_name(), but not a big deal.
Reviewed-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
One issue with the legacy kprobe code is that we don't get test coverage
with it on new kernels - I wonder if it would be worth adding a force_legacy
option to bpf_kprobe_opts? A separate issue to this change of course, but
if we had that we could add some legacy kprobe tests that would run
for new kernels as well.
Alan
>
> static int add_kprobe_event_legacy(const char *probe_name, bool retprobe,
>
