From: David Long <dave.long@linaro.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: linux-arm-kernel@lists.infradead.org,
Rabin Vincent <rabin@rab.in>,
"Jon Medhurst (Tixy)" <tixy@linaro.org>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 02/13] uprobes: allow ignoring of probe hits
Date: Mon, 21 Oct 2013 23:45:47 -0400 [thread overview]
Message-ID: <5265F4EB.2060803@linaro.org> (raw)
In-Reply-To: <20131019170214.GA8324@redhat.com>
On 10/19/13 13:02, Oleg Nesterov wrote:
> On 10/15, David Long wrote:
>>
>> @@ -1732,9 +1732,6 @@ static void handle_swbp(struct pt_regs *regs)
>> return;
>> }
>>
>> - /* change it in advance for ->handler() and restart */
>> - instruction_pointer_set(regs, bp_vaddr);
>> -
>
> Well, this looks obviously wrong. This SET_IP() has the comment ;)
>
> Note also that with this breaks __skip_sstep() on x86.
>
> Oleg.
>
Yes, and there's a missing weak stub function in there too. It was a
surprise to me that declaring an external as weak means that it quietly
ignores the fact there is no definition for it at link time, and makes
it zero. I think there may be some similar land mines elsewhere in the
kernel, unrelated to these changes or uprobes in general.
I have an updated version to go out with the v3 patches. It is working
with v3.12-rc6 on x86 and ARM, to the extent I'm able to test it.
-dl
WARNING: multiple messages have this Message-ID (diff)
From: dave.long@linaro.org (David Long)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 02/13] uprobes: allow ignoring of probe hits
Date: Mon, 21 Oct 2013 23:45:47 -0400 [thread overview]
Message-ID: <5265F4EB.2060803@linaro.org> (raw)
In-Reply-To: <20131019170214.GA8324@redhat.com>
On 10/19/13 13:02, Oleg Nesterov wrote:
> On 10/15, David Long wrote:
>>
>> @@ -1732,9 +1732,6 @@ static void handle_swbp(struct pt_regs *regs)
>> return;
>> }
>>
>> - /* change it in advance for ->handler() and restart */
>> - instruction_pointer_set(regs, bp_vaddr);
>> -
>
> Well, this looks obviously wrong. This SET_IP() has the comment ;)
>
> Note also that with this breaks __skip_sstep() on x86.
>
> Oleg.
>
Yes, and there's a missing weak stub function in there too. It was a
surprise to me that declaring an external as weak means that it quietly
ignores the fact there is no definition for it at link time, and makes
it zero. I think there may be some similar land mines elsewhere in the
kernel, unrelated to these changes or uprobes in general.
I have an updated version to go out with the v3 patches. It is working
with v3.12-rc6 on x86 and ARM, to the extent I'm able to test it.
-dl
next prev parent reply other threads:[~2013-10-22 3:45 UTC|newest]
Thread overview: 120+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-15 21:04 [PATCH v2 00/13] uprobes: Add uprobes support for ARM David Long
2013-10-15 21:04 ` David Long
2013-10-15 21:04 ` [PATCH v2 01/13] uprobes: move function declarations out of arch David Long
2013-10-15 21:04 ` David Long
2013-11-05 16:01 ` Oleg Nesterov
2013-11-05 16:01 ` Oleg Nesterov
2013-11-05 18:16 ` Oleg Nesterov
2013-11-05 18:16 ` Oleg Nesterov
2013-11-05 19:01 ` [PATCH] uprobes: Export write_opcode() as uprobe_write_opcode() Oleg Nesterov
2013-11-05 19:01 ` Oleg Nesterov
2013-11-05 19:55 ` David Long
2013-11-05 19:55 ` David Long
2013-11-05 19:13 ` [PATCH v2 01/13] uprobes: move function declarations out of arch David Long
2013-11-05 19:13 ` David Long
2013-10-15 21:04 ` [PATCH v2 02/13] uprobes: allow ignoring of probe hits David Long
2013-10-15 21:04 ` David Long
2013-10-19 17:02 ` Oleg Nesterov
2013-10-19 17:02 ` Oleg Nesterov
2013-10-22 3:45 ` David Long [this message]
2013-10-22 3:45 ` David Long
2013-10-22 11:25 ` Oleg Nesterov
2013-10-22 11:25 ` Oleg Nesterov
2013-10-22 23:56 ` David Long
2013-10-22 23:56 ` David Long
2013-10-28 18:54 ` Oleg Nesterov
2013-10-28 18:54 ` Oleg Nesterov
2013-10-30 21:11 ` David Long
2013-10-30 21:11 ` David Long
2013-10-15 21:04 ` [PATCH v2 03/13] uprobes: allow arch access to xol slot David Long
2013-10-15 21:04 ` David Long
2013-10-19 16:36 ` Oleg Nesterov
2013-10-19 16:36 ` Oleg Nesterov
2013-10-23 0:03 ` David Long
2013-10-23 0:03 ` David Long
2013-10-29 15:40 ` Oleg Nesterov
2013-10-29 15:40 ` Oleg Nesterov
2013-11-04 19:49 ` [PATCH] uprobes: introduce arch_uprobe->ixol Oleg Nesterov
2013-11-04 19:49 ` Oleg Nesterov
2013-11-04 21:25 ` David Long
2013-11-04 21:25 ` David Long
2013-11-05 16:04 ` David Long
2013-11-05 16:04 ` David Long
2013-11-05 18:01 ` Oleg Nesterov
2013-11-05 18:01 ` Oleg Nesterov
2013-11-05 18:45 ` David Long
2013-11-05 18:45 ` David Long
2013-10-15 21:04 ` [PATCH v2 04/13] uprobes: allow arch-specific initialization David Long
2013-10-15 21:04 ` David Long
2013-10-19 16:42 ` Oleg Nesterov
2013-10-19 16:42 ` Oleg Nesterov
2013-10-23 1:21 ` David Long
2013-10-23 1:21 ` David Long
2013-10-28 18:58 ` Oleg Nesterov
2013-10-28 18:58 ` Oleg Nesterov
2013-10-31 18:41 ` David Long
2013-10-31 18:41 ` David Long
2013-11-01 13:52 ` Oleg Nesterov
2013-11-01 13:52 ` Oleg Nesterov
2013-11-04 3:24 ` David Long
2013-11-04 3:24 ` David Long
2013-10-15 21:04 ` [PATCH v2 05/13] uprobes: add arch write opcode hook David Long
2013-10-15 21:04 ` David Long
2013-10-19 16:50 ` Oleg Nesterov
2013-10-19 16:50 ` Oleg Nesterov
2013-10-23 18:20 ` David Long
2013-10-23 18:20 ` David Long
2013-10-28 19:49 ` Oleg Nesterov
2013-10-28 19:49 ` Oleg Nesterov
2013-10-29 19:59 ` Oleg Nesterov
2013-10-29 19:59 ` Oleg Nesterov
2013-11-02 3:33 ` David Long
2013-11-02 3:33 ` David Long
2013-11-02 14:03 ` Oleg Nesterov
2013-11-02 14:03 ` Oleg Nesterov
2013-10-15 21:04 ` [PATCH v2 06/13] ARM: move shared uprobe/kprobe definitions into new include file David Long
2013-10-15 21:04 ` David Long
2013-10-15 21:04 ` [PATCH v2 07/13] ARM: move generic thumb instruction parsing code to new files for use by other features David Long
2013-11-13 17:09 ` Jon Medhurst (Tixy)
2013-11-13 17:09 ` Jon Medhurst (Tixy)
2013-11-14 14:13 ` David Long
2013-11-14 14:13 ` David Long
2013-10-15 21:04 ` [PATCH v2 08/13] ARM: use a function table for determining instruction interpreter actions David Long
2013-11-13 17:11 ` Jon Medhurst (Tixy)
2013-11-13 17:11 ` Jon Medhurst (Tixy)
2013-11-14 15:17 ` David Long
2013-11-14 15:17 ` David Long
2013-10-15 21:04 ` [PATCH v2 09/13] ARM: Disable jprobe selftests in thumb kernels David Long
2013-10-15 21:04 ` David Long
2013-11-07 17:26 ` Jon Medhurst (Tixy)
2013-11-07 17:26 ` Jon Medhurst (Tixy)
2013-11-10 22:57 ` David Long
2013-11-10 22:57 ` David Long
2013-10-15 21:04 ` [PATCH v2 10/13] kprobes: Remove uneeded kernel dependency on struct arch_specific_insn David Long
2013-10-15 21:04 ` David Long
2013-11-13 17:13 ` Jon Medhurst (Tixy)
2013-11-13 17:13 ` Jon Medhurst (Tixy)
2013-11-14 2:02 ` Masami Hiramatsu
2013-11-14 2:02 ` Masami Hiramatsu
2013-11-14 14:15 ` Jon Medhurst (Tixy)
2013-11-14 14:15 ` Jon Medhurst (Tixy)
2013-11-14 20:33 ` David Long
2013-11-14 20:33 ` David Long
2013-11-15 10:23 ` Masami Hiramatsu
2013-11-15 10:23 ` Masami Hiramatsu
2013-11-15 15:16 ` David Long
2013-11-15 15:16 ` David Long
2013-11-15 10:11 ` Re: " Masami Hiramatsu
2013-11-15 10:11 ` Masami Hiramatsu
2013-11-14 1:20 ` Masami Hiramatsu
2013-11-14 1:20 ` Masami Hiramatsu
2013-10-15 21:04 ` [PATCH v2 11/13] ARM: Finish renaming ARM kprobes APIs for sharing with uprobes David Long
2013-10-15 21:04 ` David Long
2013-11-13 17:16 ` Jon Medhurst (Tixy)
2013-11-13 17:16 ` Jon Medhurst (Tixy)
2013-11-15 15:45 ` David Long
2013-11-15 15:45 ` David Long
2013-10-15 21:04 ` [PATCH v2 12/13] ARM: add uprobes support David Long
2013-10-15 21:04 ` David Long
2013-10-15 21:04 ` [PATCH v2 13/13] ARM: Remove uprobes dependency on kprobes David Long
2013-10-15 21:04 ` David Long
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