Em Wed, Mar 08, 2017 at 02:11:36AM +0530, Hari Bathini escreveu:
> @@ -9691,6 +9825,11 @@ SYSCALL_DEFINE5(perf_event_open,
> return -EACCES;
> }
>
> + if (attr.namespaces) {
> + if (!capable(CAP_SYS_ADMIN))
> + return -EACCES;
> + }
> +
So, testing the first tooling patch I get:
[acme@jouet linux]$ perf record --namespaces ls
Error:
You may not have permission to collect stats.
Consider tweaking /proc/sys/kernel/perf_event_paranoid,
which controls use of the performance events system by
unprivileged users (without CAP_SYS_ADMIN).
The current value is 2:
-1: Allow use of (almost) all events by all users
>= 0: Disallow raw tracepoint access by users without CAP_IOC_LOCK
>= 1: Disallow CPU event access by users without CAP_SYS_ADMIN
>= 2: Disallow kernel profiling by users without CAP_SYS_ADMIN
To make this setting permanent, edit /etc/sysctl.conf too, e.g.:
kernel.perf_event_paranoid = -1
[acme@jouet linux]$
----------------------- 8< ---------------------------------------
So this specific case is not related to perf_event_paranoid, we need to
improve error handling here, i.e. see attr.namespaces, !CAP_SYS_ADMIN,
-EACCESS at sys_perf_event_open() -> better error message.
And perhaps we make an extra check about perf_event_paranoid... Ingo? Peter?
Can be done as a follow up patch tho, just adding entry to the collective TODO
list.
- Arnaldo
