Attempt to clarify the reasons for EACCES and EPERM errors. Signed-off-by: Vince Weaver <vincent.weaver@xxxxxxxxx> diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2 index e513905..00842df 100644 --- a/man2/perf_event_open.2 +++ b/man2/perf_event_open.2 @@ -2385,11 +2385,14 @@ field is overwritten by the kernel to be the size of the structure it was expecting. .TP .B EACCES -Returned when the requested event requires root permissions -(or a more permissive perf_event paranoid setting). -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; +Returned when the requested event requires +.B CAP_SYS_ADMIN +permissions (or a more permissive perf_event paranoid setting). +Some common cases where an unprivileged process +may encounter this error: +attaching to a process owned by a different user; +monitoring all processes (including those not belonging to the user) +on a given CPU; and not setting .I exclude_kernel when the paranoid setting requires it. @@ -2477,9 +2480,17 @@ branch tracing if it is not available, sampling if no PMU interrupt is available, and branch stacks for software events. .TP .B EPERM -Returned if sufficient permissions not available to create the event. -This includes attempting to set a breakpoint on a kernel address -and setting a ftrace function trace tracepoint. +Returned on many (but not all) architectures when an unsupported +.IR exclude_hv ", " exclude_idle ", " exclude_user ", or " exclude_kernel +setting is specified. + +It can also happen, as with +.BR EACCES , +when the requested event requires +.B CAP_SYS_ADMIN +permissions (or a more permissive perf_event paranoid setting). +This includes setting a breakpoint on a kernel address, +and (since Linux 3.13) setting a kernel function-trace tracepoint. .TP .B ESRCH Returned if attempting to attach to a process that does not exist. -- 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
