From: Helge Deller <deller@gmx.de>
To: Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>
Cc: linux-parisc@vger.kernel.org,
James Bottomley <James.Bottomley@hansenpartnership.com>,
John David Anglin <dave.anglin@bell.net>
Subject: Re: [PATCH] parisc: ftrace: get_kprobe() must be called with preempt disabled
Date: Fri, 6 Nov 2020 10:03:05 +0100 [thread overview]
Message-ID: <4859f6fe-4c96-a415-3193-e5ac888c6702@gmx.de> (raw)
In-Reply-To: <20201105214346.2d142cfc@oasis.local.home>
On 11/6/20 3:43 AM, Steven Rostedt wrote:
> On Fri, 6 Nov 2020 11:17:58 +0900
> Masami Hiramatsu <mhiramat@kernel.org> wrote:
>
>> On Tue, 3 Nov 2020 08:42:44 +0100
>> Helge Deller <deller@gmx.de> wrote:
>>
>>> As noticed by Masami Hiramatsu, get_kprobe() must be called with preempt
>>> disabled.
>>
>> Doesn't parisc ftrace implementation preempt off? Then it is required.
>>
>> Steve, can we expect that op->func() is called under preempt off always
>> on any arch or is it arch dependent?
>>
>
> Currently all kprobe function callbacks are called with preempt
> disabled, because it doesn't have the RECURSIVE_SAFE flag set. And for
> callbacks without that set, it goes through a helper function that
> disables preemption. My current patch set (which is not upstreamed yet)
> is changing that, and I just posted a new patch series that does the
> preempt disable before the get_kprobe() function for parsic and other
> archs, to handle the new code.
Seems good. Thanks!
> Thus, parsic is currently OK (without my new patch set, it's called
> with preemption disabled).
Ok.
Helge
prev parent reply other threads:[~2020-11-06 9:03 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-03 7:42 [PATCH] parisc: ftrace: get_kprobe() must be called with preempt disabled Helge Deller
2020-11-06 2:17 ` Masami Hiramatsu
2020-11-06 2:43 ` Steven Rostedt
2020-11-06 9:03 ` Helge Deller [this message]
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