Em Thu, Feb 19, 2015 at 11:31:13PM +0900, Masami Hiramatsu escreveu: > Recent linux kernel provides a blacklist of the functions which > can not be probed. perf probe can now check this blacklist before > setting new events and indicate better error message for users. > > Without this patch, > ---- > # perf probe --add vmalloc_fault > Added new event: > Failed to write event: Invalid argument > Error: Failed to add events. > ---- > With this patch > ---- > # perf probe --add vmalloc_fault > Added new event: > Warning: Skipped probing on blacklisted function: vmalloc_fault > ---- > > Signed-off-by: Masami Hiramatsu <masami.hiramatsu...@hitachi.com> > Reported-by: Arnaldo Carvalho de Melo <a...@kernel.org>
Ok, I really need to use a newer kernel on this RHEL7 box, a 4.0-rc one, as when trying this I saw no difference, but probably that is because it didn't find the kprobes blacklist, tried inserting the probe and then failed with the exact previous message... A follow up patch could try to improve the situation by saying something like: "Failed to insert the probe, maybe this is a blacklisted function and you're running an old kernel? Please check the function definition, it should not be marked as, for instance: NOKPROBE_SYMBOL(vmalloc_fault);" Anyway, applying your patch, clearly an improvement when the blacklist is available. Thanks, - Arnaldo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/