From: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
To: Song Liu <liu.song.a23@gmail.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,
Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Subject: Re: [PATCH v9 0/4] Uprobes: Support SDT markers having reference count (semaphore)
Date: Tue, 21 Aug 2018 10:12:13 +0530 [thread overview]
Message-ID: <b0b9e181-0df7-dc8f-927a-a2cf52bed93d@linux.ibm.com> (raw)
In-Reply-To: <CAPhsuW70nRkwM8C76m4c_XF4tjepdRWYezg15sTvkMUDtHZ8JQ@mail.gmail.com>
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.
Ravi
next prev parent reply other threads:[~2018-08-21 4:42 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 [this message]
2018-08-21 4:55 ` Song Liu
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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