From: Song Liu <liu.song.a23@gmail.com>
To: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Oleg Nesterov <oleg@redhat.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 v9 0/4] Uprobes: Support SDT markers having reference count (semaphore)
Date: Mon, 20 Aug 2018 21:55:38 -0700 [thread overview]
Message-ID: <CAPhsuW4SQA+uu9=a2jT+KW0Yq=yCyWqe13KtsB_ATTMiNzCXkQ@mail.gmail.com> (raw)
In-Reply-To: <b0b9e181-0df7-dc8f-927a-a2cf52bed93d@linux.ibm.com>
On Mon, Aug 20, 2018 at 9:42 PM, Ravi Bangoria
<ravi.bangoria@linux.ibm.com> wrote:
> Hi Song,
>
>> root@virt-test:~# ~/a.out
>> 11
>> semaphore 0
>> semaphore 0
>> semaphore 2 <<< when the uprobe is enabled
>
> Yes, this happens when multiple vmas points to the same file portion.
> Can you check /proc/`pgrep a.out`/maps.
>
> Logic is simple. If we are going to patch an instruction, increment the
> reference counter. If we are going to unpatch an instruction, decrement
> the reference counter. In this case, we patched instruction twice and
> thus incremented reference counter twice as well.
Yes, this makes sense.
Song
>
> Ravi
>
next prev parent reply other threads:[~2018-08-21 4:55 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-20 4:42 [PATCH v9 0/4] Uprobes: Support SDT markers having reference count (semaphore) Ravi Bangoria
2018-08-20 4:42 ` [PATCH v9 1/4] " Ravi Bangoria
2018-08-20 5:53 ` Song Liu
2018-08-21 21:35 ` Song Liu
2018-08-22 12:39 ` Srikar Dronamraju
2018-08-28 19:07 ` Song Liu
2018-08-28 19:34 ` Steven Rostedt
2018-08-20 4:42 ` [PATCH v9 2/4] Uprobes/sdt: Prevent multiple reference counter for same uprobe Ravi Bangoria
2018-08-20 5:54 ` Song Liu
2018-08-21 21:35 ` Song Liu
2018-08-20 4:42 ` [PATCH v9 3/4] trace_uprobe/sdt: " Ravi Bangoria
2018-08-21 20:46 ` Song Liu
2018-08-20 4:42 ` [PATCH v9 4/4] perf probe: Support SDT markers having reference counter (semaphore) Ravi Bangoria
2018-08-21 21:33 ` Song Liu
2018-08-30 18:45 ` Steven Rostedt
2018-08-30 18:50 ` Arnaldo Carvalho de Melo
2018-08-30 19:43 ` Steven Rostedt
2018-08-20 17:38 ` [PATCH v9 0/4] Uprobes: Support SDT markers having reference count (semaphore) Song Liu
2018-08-21 4:42 ` Ravi Bangoria
2018-08-21 4:55 ` Song Liu [this message]
2018-08-21 5:23 ` Ravi Bangoria
2018-08-21 6:20 ` Ravi Bangoria
2018-08-21 7:34 ` Naveen N. Rao
2018-08-21 11:58 ` Ravi Bangoria
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