From: peterz@infradead.org
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: "Eddy_Wu@trendmicro.com" <Eddy_Wu@trendmicro.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>,
"David S. Miller" <davem@davemloft.net>
Subject: Re: x86/kprobes: kretprobe fails to triggered if kprobe at function entry is not optimized (trigger by int3 breakpoint)
Date: Tue, 25 Aug 2020 15:30:05 +0200 [thread overview]
Message-ID: <20200825133005.GY1362448@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200825221555.a2d72c9754284feced6a8536@kernel.org>
On Tue, Aug 25, 2020 at 10:15:55PM +0900, Masami Hiramatsu wrote:
> > damn... one last problem is dangling instances.. so close.
> > We can apparently unregister a kretprobe while there's still active
> > kretprobe_instance's out referencing it.
>
> Yeah, kretprobe already provided the per-instance data (as far as
> I know, only systemtap depends on it). We need to provide it for
> such users.
> But if we only have one lock, we can avoid checking NMI because
> we can check the recursion with trylock. It is needed only if the
> kretprobe uses per-instance data. Or we can just pass a dummy
> instance on the stack.
I think it is true in general, you can unregister a rp while tasks are
preempted.
Anyway,. I think I have a solution, just need to talk to paulmck for a
bit.
> > Ignoring that issue for the moment, the below seems to actually work.
>
> OK, this looks good to me too.
> I'll make a series to rewrite kretprobe based on this patch, OK?
Please, I'll send the fix along when I have it.
next prev parent reply other threads:[~2020-08-25 13:30 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-24 12:02 x86/kprobes: kretprobe fails to triggered if kprobe at function entry is not optimized (trigger by int3 breakpoint) Eddy_Wu
2020-08-24 14:14 ` Peter Zijlstra
2020-08-24 16:18 ` Eddy_Wu
2020-08-24 18:15 ` Masami Hiramatsu
2020-08-25 7:36 ` peterz
2020-08-24 15:54 ` Masami Hiramatsu
2020-08-24 16:41 ` Eddy_Wu
2020-08-25 6:15 ` Masami Hiramatsu
2020-08-25 8:33 ` Eddy_Wu
2020-08-25 11:06 ` [PATCH] kprobes/x86: Fixes NMI context check on x86 kernel test robot
2020-08-25 12:09 ` x86/kprobes: kretprobe fails to triggered if kprobe at function entry is not optimized (trigger by int3 breakpoint) peterz
2020-08-25 13:15 ` Masami Hiramatsu
2020-08-25 13:30 ` peterz [this message]
2020-08-25 13:59 ` Masami Hiramatsu
2020-08-25 14:15 ` peterz
2020-08-25 14:10 ` peterz
2020-08-25 14:19 ` Masami Hiramatsu
2020-08-27 9:02 ` peterz
2020-08-26 7:07 ` Eddy_Wu
2020-08-26 8:22 ` Masami Hiramatsu
2020-08-26 9:06 ` Masami Hiramatsu
2020-08-26 10:00 ` Masami Hiramatsu
2020-08-26 10:25 ` peterz
2020-08-26 13:36 ` Eddy_Wu
2020-08-26 13:51 ` Masami Hiramatsu
2020-08-26 9:01 ` peterz
2020-08-26 9:21 ` peterz
2020-08-26 8:31 ` Masami Hiramatsu
2020-08-25 12:20 ` [PATCH] kprobes/x86: Fixes NMI context check on x86 kernel test robot
2020-08-25 12:25 ` kernel test robot
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