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From: Arnaldo Carvalho de Melo <>
To: Masami Hiramatsu <>
Cc: Peter Zijlstra <>,, Ingo Molnar <>,
	Linux Kernel Mailing List <>
Subject: Re: [PATCH perf/core ] perf-probe: Check kprobes blacklist when adding new events
Date: Wed, 25 Feb 2015 18:50:05 -0300
Message-ID: <> (raw)
In-Reply-To: <20150219143113.14434.5387.stgit@localhost.localdomain>

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 <>
> Reported-by: Arnaldo Carvalho de Melo <>

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

"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


Anyway, applying your patch, clearly an improvement when the blacklist
is available.


- Arnaldo

  reply index

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-30  9:37 [PATCH perf/core 0/2] perf-probe: bugfix and update Masami Hiramatsu
2015-01-30  9:37 ` [PATCH perf/core 1/2] [BUGFIX] perf-probe: Fix to handle optimized not-inlined but has no instance Masami Hiramatsu
2015-01-30 14:21   ` Arnaldo Carvalho de Melo
2015-01-30 14:32     ` Arnaldo Carvalho de Melo
2015-02-02  8:41       ` Masami Hiramatsu
2015-02-08  8:37     ` Masami Hiramatsu
2015-02-11 20:42       ` Arnaldo Carvalho de Melo
2015-02-19 14:31         ` [PATCH perf/core ] perf-probe: Check kprobes blacklist when adding new events Masami Hiramatsu
2015-02-25 21:50           ` Arnaldo Carvalho de Melo [this message]
2015-02-28  9:30           ` [tip:perf/core] perf probe: " tip-bot for Masami Hiramatsu
2015-02-18 18:25   ` [tip:perf/core] perf probe: Fix to handle optimized not-inlined functions tip-bot for Masami Hiramatsu
2015-01-30  9:37 ` [PATCH perf/core 2/2] [DOC] perf-probe: Update perf-probe document Masami Hiramatsu
2015-02-18 18:25   ` [tip:perf/core] perf probe: Update man page tip-bot for Masami Hiramatsu

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