From: Andrea Righi <righi.andrea@gmail.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
Ingo Molnar <mingo@redhat.com>,
peterz@infradead.org,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/2] kprobes: Fix kretprobe incorrect stacking order problem
Date: Mon, 7 Jan 2019 20:52:09 +0100 [thread overview]
Message-ID: <20190107195209.GB5966@xps-13> (raw)
In-Reply-To: <20190107142749.34231bb6@gandalf.local.home>
On Mon, Jan 07, 2019 at 02:27:49PM -0500, Steven Rostedt wrote:
> On Mon, 7 Jan 2019 19:34:44 +0100
> Andrea Righi <righi.andrea@gmail.com> wrote:
>
> > On Mon, Jan 07, 2019 at 10:31:34PM +0900, Masami Hiramatsu wrote:
> > ...
> > > BTW, this is not all of issues. To remove CONFIG_KPROBE_EVENTS_ON_NOTRACE
> > > I'm trying to find out other notrace functions which can cause
> > > kernel crash by probing. Mostly done on x86, so I'll post it
> > > after this series.
> >
> > Not sure if you found it already, but it looks like some of the
> > _raw_spin_lock/unlock* functions (when they're not inlined) are causing
> > the same problem (or something similar), I can deadlock the system by
> > doing this for example:
> >
> > echo "r:event_1 __fdget" >> kprobe_events
> > echo "r:event_2 _raw_spin_lock_irqsave" >> kprobe_events
> > echo 1 > events/kprobes/enable
> > [DEADLOCK]
> >
> > Sending the following just in case...
> >
>
> Ug, kretprobe calls spinlocks in the callback? I wonder if we can
> remove them.
>
> I'm guessing this is a different issue than the one that this patch
> fixes. This sounds like we are calling kretprobe from kretprobe?
>
> -- Steve
kretprobe_trampoline()
-> trampoline_handler()
-> kretprobe_hash_lock()
-> raw_spin_lock_irqsave()
If we put a kretprobe to raw_spin_lock_irqsave() it looks like
kretprobe is going to call kretprobe...
-Andrea
next prev parent reply other threads:[~2019-01-07 19:52 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-07 13:31 [PATCH 0/2] kprobes: Fix kretprobe incorrect stacking order problem Masami Hiramatsu
2019-01-07 13:32 ` [PATCH 1/2] x86/kprobes: Verify stack frame on kretprobe Masami Hiramatsu
2019-01-07 13:32 ` [PATCH 2/2] kprobes: Mark ftrace mcount handler functions nokprobe Masami Hiramatsu
2019-01-07 14:55 ` Andrea Righi
2019-01-07 17:29 ` Steven Rostedt
2019-01-08 2:41 ` Masami Hiramatsu
2019-01-08 2:40 ` Masami Hiramatsu
2019-01-07 17:23 ` kbuild test robot
2019-01-07 17:38 ` kbuild test robot
2019-01-07 17:28 ` [PATCH 0/2] kprobes: Fix kretprobe incorrect stacking order problem Andrea Righi
2019-01-07 18:34 ` Andrea Righi
2019-01-07 19:27 ` Steven Rostedt
2019-01-07 19:52 ` Andrea Righi [this message]
2019-01-07 19:59 ` Steven Rostedt
2019-01-07 21:19 ` Andrea Righi
2019-01-07 21:28 ` Steven Rostedt
2019-01-07 21:34 ` Andrea Righi
2019-01-08 2:56 ` Masami Hiramatsu
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