Am 15.04.2014 20:25, schrieb Vince Weaver: > On Mon, 14 Apr 2014, Michael Kerrisk (man-pages) wrote: > >> >> EACCES Returned when the requested event requires root permis‐ >> sions (or a more permissive perf_event paranoid set‐ >> ting). Some common cases where an unprivileged process >> may encounter this error: are attaching to a process >> owned by a different user; monitoring all processes on a >> given CPU; and not setting exclude_kernel when the para‐ >> noid setting requires it. >> >> But, now I have some more questions: >> >> * What are "root permissions" here? It's these days usual to express >> things precisely in terms of the required capability. > > Yes, I guess that should really be CAP_SYS_ADMIN > >> * I am puzzled by "monitoring all processes on a CPU"? So, monitoring >> _some_ (i.e., < all) processes on a CPU won't trigger this error? > > I was a bit confused here. > > A regular user can monitor "the specified process on CPU X" or "the > specified process on any CPU". > > A user running as root can also monitor "all procceses belonging to anyone > on CPU X" > why not "can monitor any process" ? re, wh > Other combinations aren't possible. > >>>>> +.B EPERM >>>>> +Returned if sufficient permissions not available to create the event. >> >> Again, somewhere here, the text should mention the required capability. > > Yes, it's CAP_SYS_ADMIN again. > >>> This is a recent change. >> >> So, the text should mention a kernel version number. Could you patch >> that please. I guess it should be something like: >> >> and (since Linux 3.??) setting an ftrace function-trace tracepoint > > Yes, I'll do that. > > Vince -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
