From: masami.hiramatsu.pt@hitachi•com (Masami Hiramatsu)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH RFC 2/6] arm64: Kprobes with single stepping support
Date: Sat, 09 Nov 2013 18:10:52 +0900 [thread overview]
Message-ID: <527DFC1C.1020107@hitachi.com> (raw)
In-Reply-To: <20131108165639.GD15074@mudshark.cambridge.arm.com>
(2013/11/09 1:56), Will Deacon wrote:
> Hi Sandeepa,
>
> On Thu, Oct 17, 2013 at 12:17:47PM +0100, Sandeepa Prabhu wrote:
>> Add support for basic kernel probes(kprobes), jump probes (jprobes)
>> for ARM64.
>
> I think this series will conflict quite heavily with the jump_label series,
> since they both introduce some common instruction manipulation code. On the
> debug side, there will also be conflicts with the kgdb series, so it might
> make sense for us to merge those two first, then you can rebase on a stable
> branch from us.
[...]
> In fact, how do you avoid a race with hardware breakpoints? E.g., somebody
> places a hardware breakpoint on an instruction in the kernel for which
> kprobes has patched in a brk. We take the hardware breakpoint, disable the
> breakpoint and set up a single step before returning to the brk. The brk
> then traps, but we must take care not to disable single-step and/or unmask
> debug exceptions, because that will cause the hardware breakpoint code to
> re-arm its breakpoint before we've stepped off the brk instruction.
Hmm, frankly to say, this kind of race issue is not seriously discussed
on x86 too, since kgdb is still a special tool (not used on the production
system).
I think under such situation kgdb operator must have full control of the
system, and he can (and has to) avoid such kind of race.
Thank you,
--
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt at hitachi.com
next prev parent reply other threads:[~2013-11-09 9:10 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-17 11:17 [PATCH RFC v2 0/6] ARM64: Add kernel probes(Kprobes) support Sandeepa Prabhu
2013-10-17 11:17 ` [PATCH RFC v4 1/6] arm64: support single-step and breakpoint handler hooks Sandeepa Prabhu
2013-10-25 15:22 ` Will Deacon
2013-12-03 14:33 ` Sandeepa Prabhu
2013-12-03 19:44 ` Will Deacon
2013-10-17 11:17 ` [PATCH RFC 2/6] arm64: Kprobes with single stepping support Sandeepa Prabhu
2013-11-08 16:56 ` Will Deacon
2013-11-09 9:10 ` Masami Hiramatsu [this message]
2013-11-11 5:39 ` Sandeepa Prabhu
2013-11-11 7:54 ` Masami Hiramatsu
2013-11-11 10:51 ` Masami Hiramatsu
2013-11-11 10:58 ` Will Deacon
2013-11-11 17:32 ` Masami Hiramatsu
2013-11-12 6:23 ` Sandeepa Prabhu
2013-11-12 7:27 ` Masami Hiramatsu
2013-11-12 8:44 ` Sandeepa Prabhu
2013-11-12 10:17 ` Masami Hiramatsu
2013-11-12 10:55 ` Sandeepa Prabhu
2013-11-12 14:11 ` Masami Hiramatsu
2013-11-12 16:59 ` Steven Rostedt
2013-11-13 16:05 ` Masami Hiramatsu
[not found] ` <CA+b37P1sNsEXrJFfVL51sZ-SeGNCBiwXnOwCiFY8CBwSXPw+mQ@mail.gmail.com>
2013-11-13 7:08 ` Sandeepa Prabhu
2013-11-13 14:07 ` Masami Hiramatsu
2013-11-13 14:31 ` Will Deacon
2013-11-13 15:55 ` Sandeepa Prabhu
2013-11-15 16:39 ` Will Deacon
2013-11-18 6:55 ` Sandeepa Prabhu
2013-11-18 8:51 ` Sandeepa Prabhu
2013-11-13 13:58 ` Peter Zijlstra
2013-11-13 14:20 ` Will Deacon
2013-11-11 5:35 ` Sandeepa Prabhu
2013-11-11 11:21 ` Will Deacon
2013-11-12 6:52 ` Sandeepa Prabhu
2013-11-15 16:37 ` Will Deacon
2013-11-18 6:43 ` Sandeepa Prabhu
2013-10-17 11:17 ` [PATCH RFC 3/6] arm64: Kprobes instruction simulation support Sandeepa Prabhu
2013-11-08 17:03 ` Will Deacon
2013-11-11 5:58 ` Sandeepa Prabhu
2013-10-17 11:17 ` [PATCH RFC 4/6] arm64: Add kernel return probes support(kretprobes) Sandeepa Prabhu
2013-11-08 17:04 ` Will Deacon
2013-11-11 4:29 ` Sandeepa Prabhu
2013-11-11 7:53 ` AKASHI Takahiro
2013-11-11 8:55 ` Sandeepa Prabhu
2013-10-17 11:17 ` [PATCH RFC 5/6] arm64: Enable kprobes support for arm64 platform Sandeepa Prabhu
2013-10-17 11:17 ` [PATCH RFC 6/6] kprobes: Add cases for arm and arm64 in sample module Sandeepa Prabhu
2013-10-25 15:24 ` Will Deacon
2013-11-06 11:05 ` Sandeepa Prabhu
2013-10-18 8:32 ` [PATCH RFC v2 0/6] ARM64: Add kernel probes(Kprobes) support Masami Hiramatsu
2013-10-21 4:17 ` Sandeepa Prabhu
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