From: Song Liu <liu.song.a23@gmail.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Steven Rostedt <rostedt@goodmis.org>,
mhiramat@kernel.org, Peter Zijlstra <peterz@infradead.org>,
mingo@redhat.com, acme@kernel.org,
alexander.shishkin@linux.intel.com, jolsa@redhat.com,
namhyung@kernel.org, open list <linux-kernel@vger.kernel.org>,
ananth@linux.vnet.ibm.com,
Alexis Berlemont <alexis.berlemont@gmail.com>,
naveen.n.rao@linux.vnet.ibm.com,
linux-arm-kernel@lists.infradead.org, linux-mips@linux-mips.org,
linux@armlinux.org.uk, ralf@linux-mips.org, paul.burton@mips.com
Subject: Re: [PATCH v8 3/6] Uprobes: Support SDT markers having reference count (semaphore)
Date: Mon, 13 Aug 2018 10:12:14 -0700 [thread overview]
Message-ID: <CAPhsuW4KT=6vR_0ogTy_+Fwcz7cZ0Rac8sYohLngQmEBCd0HLw@mail.gmail.com> (raw)
In-Reply-To: <20180813131723.GC28360@redhat.com>
On Mon, Aug 13, 2018 at 6:17 AM, Oleg Nesterov <oleg@redhat.com> wrote:
> On 08/13, Ravi Bangoria wrote:
>>
>> > But damn, process creation (exec) is trivial. We could add a new uprobe_exec()
>> > hook and avoid delayed_uprobe_install() in uprobe_mmap().
>>
>> I'm sorry. I didn't get this.
>
> Sorry for confusion...
>
> I meant, if only exec*( could race with _register(), we could add another uprobe
> hook which updates all (delayed) counters before return to user-mode.
>
>> > Afaics, the really problematic case is dlopen() which can race with _register()
>> > too, right?
>>
>> dlopen() should internally use mmap() right? So what is the problem here? Can
>> you please elaborate.
>
> What I tried to say is that we can't avoid uprobe_mmap()->delayed_uprobe_install()
> because dlopen() can race with _register() too, just like exec.
>
> Oleg.
>
How about we do delayed_uprobe_install() per file? Say we keep a list
of delayed_uprobe
in load_elf_binary(). Then we can install delayed_uprobe after loading
all sections of the
file.
Song
WARNING: multiple messages have this Message-ID (diff)
From: liu.song.a23@gmail.com (Song Liu)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v8 3/6] Uprobes: Support SDT markers having reference count (semaphore)
Date: Mon, 13 Aug 2018 10:12:14 -0700 [thread overview]
Message-ID: <CAPhsuW4KT=6vR_0ogTy_+Fwcz7cZ0Rac8sYohLngQmEBCd0HLw@mail.gmail.com> (raw)
In-Reply-To: <20180813131723.GC28360@redhat.com>
On Mon, Aug 13, 2018 at 6:17 AM, Oleg Nesterov <oleg@redhat.com> wrote:
> On 08/13, Ravi Bangoria wrote:
>>
>> > But damn, process creation (exec) is trivial. We could add a new uprobe_exec()
>> > hook and avoid delayed_uprobe_install() in uprobe_mmap().
>>
>> I'm sorry. I didn't get this.
>
> Sorry for confusion...
>
> I meant, if only exec*( could race with _register(), we could add another uprobe
> hook which updates all (delayed) counters before return to user-mode.
>
>> > Afaics, the really problematic case is dlopen() which can race with _register()
>> > too, right?
>>
>> dlopen() should internally use mmap() right? So what is the problem here? Can
>> you please elaborate.
>
> What I tried to say is that we can't avoid uprobe_mmap()->delayed_uprobe_install()
> because dlopen() can race with _register() too, just like exec.
>
> Oleg.
>
How about we do delayed_uprobe_install() per file? Say we keep a list
of delayed_uprobe
in load_elf_binary(). Then we can install delayed_uprobe after loading
all sections of the
file.
Song
next prev parent reply other threads:[~2018-08-13 17:12 UTC|newest]
Thread overview: 84+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-09 4:18 [PATCH v8 0/6] Uprobes: Support SDT markers having reference count (semaphore) Ravi Bangoria
2018-08-09 4:18 ` Ravi Bangoria
2018-08-09 4:18 ` [PATCH v8 1/6] Uprobes: Simplify uprobe_register() body Ravi Bangoria
2018-08-09 4:18 ` Ravi Bangoria
2018-08-11 8:00 ` Song Liu
2018-08-11 8:00 ` Song Liu
2018-08-13 8:56 ` Srikar Dronamraju
2018-08-13 8:56 ` Srikar Dronamraju
2018-08-14 0:07 ` Steven Rostedt
2018-08-14 0:07 ` Steven Rostedt
2018-08-09 4:18 ` [PATCH v8 2/6] Uprobe: Additional argument arch_uprobe to uprobe_write_opcode() Ravi Bangoria
2018-08-09 4:18 ` Ravi Bangoria
2018-08-11 8:01 ` Song Liu
2018-08-11 8:01 ` Song Liu
2018-08-13 8:51 ` Srikar Dronamraju
2018-08-13 8:51 ` Srikar Dronamraju
2018-08-09 4:18 ` [PATCH v8 3/6] Uprobes: Support SDT markers having reference count (semaphore) Ravi Bangoria
2018-08-09 4:18 ` Ravi Bangoria
2018-08-09 14:38 ` Oleg Nesterov
2018-08-09 14:38 ` Oleg Nesterov
2018-08-10 19:58 ` Steven Rostedt
2018-08-10 19:58 ` Steven Rostedt
2018-08-11 6:14 ` Song Liu
2018-08-11 6:14 ` Song Liu
2018-08-14 0:01 ` Steven Rostedt
2018-08-14 0:01 ` Steven Rostedt
2018-08-14 0:05 ` Steven Rostedt
2018-08-14 0:05 ` Steven Rostedt
2018-08-11 7:57 ` Song Liu
2018-08-11 7:57 ` Song Liu
2018-08-11 15:37 ` Steven Rostedt
2018-08-11 15:37 ` Steven Rostedt
2018-08-13 5:47 ` Ravi Bangoria
2018-08-13 5:47 ` Ravi Bangoria
2018-08-13 7:38 ` Ravi Bangoria
2018-08-13 7:38 ` Ravi Bangoria
2018-08-13 11:50 ` Oleg Nesterov
2018-08-13 11:50 ` Oleg Nesterov
2018-08-13 13:01 ` Ravi Bangoria
2018-08-13 13:01 ` Ravi Bangoria
2018-08-13 13:17 ` Oleg Nesterov
2018-08-13 13:17 ` Oleg Nesterov
2018-08-13 14:26 ` Ravi Bangoria
2018-08-13 14:26 ` Ravi Bangoria
2018-08-13 14:51 ` Oleg Nesterov
2018-08-13 14:51 ` Oleg Nesterov
2018-08-13 17:12 ` Song Liu [this message]
2018-08-13 17:12 ` Song Liu
2018-08-14 4:37 ` Ravi Bangoria
2018-08-14 4:37 ` Ravi Bangoria
2018-08-14 16:35 ` Song Liu
2018-08-14 16:35 ` Song Liu
2018-08-14 0:03 ` Steven Rostedt
2018-08-14 0:03 ` Steven Rostedt
2018-08-13 16:50 ` Song Liu
2018-08-13 16:50 ` Song Liu
2018-08-13 10:03 ` Srikar Dronamraju
2018-08-13 10:03 ` Srikar Dronamraju
2018-08-13 11:23 ` Oleg Nesterov
2018-08-13 11:23 ` Oleg Nesterov
2018-08-14 8:56 ` Ravi Bangoria
2018-08-14 8:56 ` Ravi Bangoria
2018-08-09 4:18 ` [PATCH v8 4/6] Uprobes/sdt: Prevent multiple reference counter for same uprobe Ravi Bangoria
2018-08-09 4:18 ` Ravi Bangoria
2018-08-11 8:04 ` Song Liu
2018-08-11 8:04 ` Song Liu
2018-08-13 8:50 ` Srikar Dronamraju
2018-08-13 8:50 ` Srikar Dronamraju
2018-08-09 4:18 ` [PATCH v8 5/6] trace_uprobe/sdt: " Ravi Bangoria
2018-08-09 4:18 ` Ravi Bangoria
2018-08-11 8:12 ` Song Liu
2018-08-11 8:12 ` Song Liu
2018-08-13 8:19 ` Ravi Bangoria
2018-08-13 8:19 ` Ravi Bangoria
2018-08-13 8:49 ` Srikar Dronamraju
2018-08-13 8:49 ` Srikar Dronamraju
2018-08-13 16:27 ` Song Liu
2018-08-13 16:27 ` Song Liu
2018-08-13 8:48 ` Srikar Dronamraju
2018-08-13 8:48 ` Srikar Dronamraju
2018-08-09 4:18 ` [PATCH v8 6/6] perf probe: Support SDT markers having reference counter (semaphore) Ravi Bangoria
2018-08-09 4:18 ` Ravi Bangoria
2018-08-13 16:55 ` [PATCH v8 0/6] Uprobes: Support SDT markers having reference count (semaphore) Oleg Nesterov
2018-08-13 16:55 ` Oleg Nesterov
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