On 11/20/2013 09:56 AM, Steven Rostedt wrote: > On Wed, 20 Nov 2013 12:36:00 -0500 > "Frank Ch. Eigler" <fche@xxxxxxxxxx> wrote: > >> Hi - >> >>>> Does this new blacklist cover enough that the kernel now survives a >>>> broadly wildcarded perf-probe, e.g. over e.g. all of its kallsyms? >>> >>> That's generally the purpose of the annotations - if it doesn't then >>> that's a bug. >> >> AFAIK, no kernel since kprobes was introduced has ever stood up to >> that test. perf probe lacks the wildcarding powers of systemtap, so >> one needs to resort to something like: >> >> # cat /proc/kallsyms | grep ' [tT] ' | while read addr type symbol; do >> perf probe $symbol >> done > > I'm curious to why one would do that. IIUC, perf now has function > tracing support. Then consider something like probing all inline "call" sites, which will be sprinkled in the middle where ftrace doesn't apply. The point is not whether there's an alternative - kprobes really ought to be wholly safe regardless. Slow, if you did such broad probing, sure, but still safe. And a real use-case probably wouldn't probe *all* functions/inlines, but it illustrates that there are at least a few in the full set that don't behave well. -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
