> I'm resuming work on this and would like to know your opinion and concerns about the following proposal: Thank you so much for doing this! > - Add s_dev from nsfs to ns_common, so now ns_common will have inode and > device to identify the namespace, as in the future namespaces will need to match against ino and device. > > - That will allow us to remove the call to ns_match on because the values > checked are now present in ns_common (ino and dev_t). > > - Add a new helper named bpf_get_current_pid_tgid_from_ns that will return > pid/tgid from the current task if pid ns matches ino and dev supplied by the > user as now both values are in ns_common. Maybe that's what you meant but I would express it this way: return pid/tgid from the current task as observed from the pid namespace matching ino/dev, or return error if the task is outside that pid namespace or its descendants (i.e. the pid namespace matching ino/dev can't see the task). Thanks, Blaise On Fri, Nov 13, 2020 at 1:59 PM Yonghong Song <yhs@xxxxxx> wrote: On 11/13/20 6:34 AM, carlos antonio neira bustos wrote: > Hi Blaise and Daniel, > > > I was following a couple of months ago how bpftrace was going to handle > this situation. I thought this PR > https://github.com/iovisor/bpftrace/pull/1602 > <https://github.com/iovisor/bpftrace/pull/1602> was going to be merged > but just found today that is not working. > > I agree with Yonghong Song on the approach of using the two helpers > (bpf_get_pid_tgid() and bpf_get_ns_current_pid_tgid()) to move forward > on the short term, bpf_get_ns_current_pid_tgid works as a replacement > to bpf_get_pid_tgid when you are instrumenting inside a container. > > But the use case described by Blaise is one I would like to use bpftrace, > > If nobody is against it, I could start working on a new helper to > address that situation as I need to have bpftrace working in that scenario. Yes, please. Thanks! > > For my understanding of the problem the new helper should be able to > return pid/tgid from a target namespace, is that correct?. Yes. This way, the stack trace can correlate to target namespace for symbolization purpose. > > > Bests > > [...]
