On Fri, Mar 13, 2020 at 10:39:41AM +0000, Quentin Monnet wrote: > 2020-03-12 17:45 UTC-0700 ~ Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx> > > On Wed, Mar 4, 2020 at 12:42 PM Carlos Neira <cneirabustos@xxxxxxxxx> wrote: > >> > >> Currently bpf_get_current_pid_tgid(), is used to do pid filtering in bcc's > >> scripts but this helper returns the pid as seen by the root namespace which is > >> fine when a bcc script is not executed inside a container. > >> When the process of interest is inside a container, pid filtering will not work > >> if bpf_get_current_pid_tgid() is used. > >> This helper addresses this limitation returning the pid as it's seen by the current > >> namespace where the script is executing. > >> > >> In the future different pid_ns files may belong to different devices, according to the > >> discussion between Eric Biederman and Yonghong in 2017 Linux plumbers conference. > >> To address that situation the helper requires inum and dev_t from /proc/self/ns/pid. > >> This helper has the same use cases as bpf_get_current_pid_tgid() as it can be > >> used to do pid filtering even inside a container. > > > > Applied. Thanks. > > There was one spurious trailing whitespace that I fixed in patch 3 > > and missing .gitignore update for test_current_pid_tgid_new_ns. > > Could you please follow up with another patch to fold > > test_current_pid_tgid_new_ns into test_progs. > > I'd really like to consolidate all tests into single binary. > > > > Compiling bpftool (with libbpf now relying on bpf_helper_defs.h > generated from helpers documentation), I observe the following > warning: > > .output/bpf_helper_defs.h:2834:72: warning: declaration of 'struct bpf_pidns_info' will not be visible outside of this function [-Wvisibility] > static int (*bpf_get_ns_current_pid_tgid)(__u64 dev, __u64 ino, struct bpf_pidns_info *nsdata, __u32 size) = (void *) 120; > > Would it be possible to address this as part of the follow-up too, > please? I think the fix would be to add "struct bpf_pidns_info" > to type_fds (I see it was added to known_types already) in > scripts/bpf_helpers_doc.py. > > Thanks, > Quentin Thanks for checking this out Quentin, I'm sorry I'll start working on this follow-up patch to fix this. Bests
