From: Steve Capper <steve.capper@linaro.org>
To: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: David Long <dave.long@linaro.org>,
"Jon Medhurst (Tixy)" <tixy@linaro.org>,
Russell King <linux@arm.linux.org.uk>,
Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
Sandeepa Prabhu <sandeepa.prabhu@linaro.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
William Cohen <wcohen@redhat.com>,
David Miller <davem@davemloft.net>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v3 0/5] ARM64: Add kernel probes(Kprobes) support
Date: Tue, 9 Dec 2014 13:33:42 +0000 [thread overview]
Message-ID: <20141209133340.GA20265@linaro.org> (raw)
In-Reply-To: <54804B1F.3020703@hitachi.com>
On Thu, Dec 04, 2014 at 08:53:03PM +0900, Masami Hiramatsu wrote:
> (2014/12/04 20:29), Steve Capper wrote:
>
> >> I'd like to ask you to try my fix on your machine, with my reproducing
> >> methods. (do not use sytemtap nor perf, those can have other issues)
> >>
> >
> > Thank you Masami,
> >
> > I tried the following commands:
> >
> > echo "p:trace_event_buffer_lock_reserve
> > trace_event_buffer_lock_reserve" >
> > /sys/kernel/debug/tracing/kprobe_events
> > echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable
> > echo 1 > /sys/kernel/debug/tracing/events/sched/sched_process_exec/enable
> >
> > The system appeared okay, I then cat'ed out:
> > # cat /sys/kernel/debug/tracing/kprobe_profile
> > trace_event_buffer_lock_reserve 25 25
> >
> > I got similar output (i.e. no crashes) both with and without the
> > interrupt fix you recommended.
> >
> > I'm not sure how to interpret this, please let me know if you would
> > like me to run any other tests?
> >
> > (I did also try your proposed fix with perf + memcpy and that crashed
> > in a similar way as before).
>
> Hmm, then the bug is still there, and the bug may not be in the recursive
> call path... We need to find another suspicious code in the patch.
>
Not sure if this is helpful, but the following also caused a crash for
me:
echo "p:trace_event_buffer_lock_reserve trace_event_buffer_lock_reserve" > /sys/kernel/debug/tracing/kprobe_events
echo "p:memcpy memcpy" >> /sys/kernel/debug/tracing/kprobe_events
echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable
[immediate crash]
The crash point for me is in the arm64 ASID allocator, it again looks
like the interrupts are in an unexpected state.
(check_and_switch_context goes down the irqs disabled code path, I
think incorrectly).
This occurred for me both with and without the proposed irq saving fix.
I will do some more digging.
Cheers,
--
Steve
next prev parent reply other threads:[~2014-12-09 13:33 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-18 6:32 [PATCH v3 0/5] ARM64: Add kernel probes(Kprobes) support David Long
2014-11-18 6:32 ` [PATCH v3 1/5] arm64: Kprobes with single stepping support David Long
2014-11-18 13:28 ` Jon Medhurst (Tixy)
2014-11-21 4:28 ` David Long
2014-11-18 14:38 ` William Cohen
2014-11-18 14:39 ` William Cohen
2014-11-18 14:56 ` Will Deacon
2014-11-19 11:21 ` Sandeepa Prabhu
2014-11-19 11:25 ` Will Deacon
2014-11-19 14:55 ` David Long
2014-11-20 5:10 ` Sandeepa Prabhu
2014-11-26 6:46 ` David Long
2014-11-26 10:09 ` Will Deacon
2014-12-22 10:10 ` Pratyush Anand
2014-11-18 6:32 ` [PATCH v3 2/5] arm64: Kprobes instruction simulation support David Long
2014-11-18 14:43 ` William Cohen
2014-11-18 6:32 ` [PATCH v3 3/5] arm64: Add kernel return probes support(kretprobes) David Long
2014-11-18 14:50 ` William Cohen
2014-11-18 6:32 ` [PATCH v3 4/5] kprobes: Add arm64 case in kprobe example module David Long
2014-11-18 6:32 ` [PATCH v3 5/5] arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature David Long
2014-11-18 14:52 ` Will Deacon
2014-11-20 7:20 ` Masami Hiramatsu
2014-11-21 6:16 ` David Long
2014-11-20 15:02 ` [PATCH v3 0/5] ARM64: Add kernel probes(Kprobes) support Steve Capper
2014-11-26 8:33 ` Masami Hiramatsu
2014-11-26 10:03 ` Steve Capper
2014-11-26 17:46 ` David Long
2014-11-26 18:59 ` Steve Capper
2014-11-27 6:07 ` Masami Hiramatsu
2014-11-28 16:01 ` Steve Capper
2014-12-01 9:37 ` Masami Hiramatsu
2014-12-02 19:27 ` William Cohen
2014-12-02 20:00 ` William Cohen
2014-12-03 3:36 ` Masami Hiramatsu
2014-12-03 14:54 ` William Cohen
2014-12-03 22:54 ` David Long
2014-12-04 0:02 ` David Long
2014-12-04 1:16 ` William Cohen
2014-12-04 2:48 ` David Long
2014-12-04 10:21 ` Steve Capper
2014-12-04 10:43 ` Masami Hiramatsu
2014-12-04 11:29 ` Steve Capper
2014-12-04 11:53 ` Masami Hiramatsu
2014-12-09 13:33 ` Steve Capper [this message]
2014-12-09 14:27 ` David Long
2014-12-10 16:38 ` Steve Capper
2014-12-12 22:42 ` David Long
2014-12-12 23:10 ` Steve Capper
2014-12-15 5:58 ` Masami Hiramatsu
2014-12-15 6:29 ` David Long
2014-12-05 5:08 ` William Cohen
2014-11-27 5:13 ` Masami Hiramatsu
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