On 10/29/21 6:46 AM, Martin KaFai Lau wrote: > On Thu, Oct 28, 2021 at 06:43:57PM +0200, Florent Revest wrote: >> Allow the helper to be called from the perf_event_mmap hook. This is >> convenient to lookup vma->vm_file and implement a similar logic as >> perf_event_mmap_event in BPF. > From struct vm_area_struct: > struct file * vm_file; /* File we map to (can be NULL). */ > > Under perf_event_mmap, vm_file won't be NULL or bpf_d_path can handle it? > Hmm, is perf_event_mmap a proper tracing target ? It does not appear in /sys/kernel/debug/tracing/available_filter_functions. I tried using kprobe/fentry to attach to it, both failed. >> >> Signed-off-by: Florent Revest <revest@xxxxxxxxxxxx> >> --- >> kernel/trace/bpf_trace.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c >> index cbcd0d6fca7c..f6e301c775a5 100644 >> --- a/kernel/trace/bpf_trace.c >> +++ b/kernel/trace/bpf_trace.c >> @@ -922,6 +922,9 @@ BTF_ID(func, vfs_fallocate) >> BTF_ID(func, dentry_open) >> BTF_ID(func, vfs_getattr) >> BTF_ID(func, filp_close) >> +#ifdef CONFIG_PERF_EVENTS >> +BTF_ID(func, perf_event_mmap) >> +#endif >> BTF_SET_END(btf_allowlist_d_path) >> >> static bool bpf_d_path_allowed(const struct bpf_prog *prog) >> -- >> 2.33.0.1079.g6e70778dc9-goog >> --Hengqi
