From: Peter Zijlstra <peterz@infradead.org>
To: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: mhiramat@kernel.org, ananth@linux.ibm.com,
Christoph Hellwig <hch@lst.de>,
linux-kernel@vger.kernel.org, mingo@kernel.org,
rostedt@goodmis.org, x86@kernel.org
Subject: Re: [PATCH] kprobes: Do not increment probe miss count in the fault handler
Date: Tue, 1 Jun 2021 15:20:32 +0200 [thread overview]
Message-ID: <YLY0INyDtfjgVrXv@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20210601120150.672652-1-naveen.n.rao@linux.vnet.ibm.com>
On Tue, Jun 01, 2021 at 05:31:50PM +0530, Naveen N. Rao wrote:
> Kprobes has a counter 'nmissed', that is used to count the number of
> times a probe handler was not called. This generally happens when we hit
> a kprobe while handling another kprobe.
>
> However, if one of the probe handlers causes a fault, we are currently
> incrementing 'nmissed'. The comment in fault handler indicates that this
> can be used to account faults taken by the probe handlers. But, this has
> never been the intention as is evident from the comment above 'nmissed'
> in 'struct kprobe':
>
> /*count the number of times this probe was temporarily disarmed */
> unsigned long nmissed;
>
> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
> ---
> I'm posting this here so that these can go together, if the patch is ok
> otherwise.
I had the other two queued in perf/core and was about to push then to
tip, Masami are you good with adding this on top?
next prev parent reply other threads:[~2021-06-01 13:20 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-25 7:25 [PATCH 0/2] kprobes: Remove kprobe::fault_handler Peter Zijlstra
2021-05-25 7:25 ` [PATCH 1/2] " Peter Zijlstra
2021-05-25 14:06 ` Masami Hiramatsu
2021-05-26 10:50 ` Naveen N. Rao
2021-05-26 13:51 ` Masami Hiramatsu
2021-06-01 12:01 ` [PATCH] kprobes: Do not increment probe miss count in the fault handler Naveen N. Rao
2021-06-01 13:20 ` Peter Zijlstra [this message]
2021-06-01 23:48 ` Masami Hiramatsu
2021-06-04 13:38 ` [tip: perf/core] " tip-bot2 for Naveen N. Rao
2021-06-01 14:04 ` [tip: perf/core] kprobes: Remove kprobe::fault_handler tip-bot2 for Peter Zijlstra
2021-05-25 7:25 ` [PATCH 2/2] x86,kprobes: WARN if kprobes tries to handle a fault Peter Zijlstra
2021-05-25 14:21 ` Masami Hiramatsu
2021-06-01 14:04 ` [tip: perf/core] " tip-bot2 for Peter Zijlstra
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