From: Oleg Nesterov <oleg@redhat.com>
To: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: mhiramat@kernel.org, peterz@infradead.org,
srikar@linux.vnet.ibm.com, acme@kernel.org,
ananth@linux.vnet.ibm.com, akpm@linux-foundation.org,
alexander.shishkin@linux.intel.com, alexis.berlemont@gmail.com,
corbet@lwn.net, dan.j.williams@intel.com,
gregkh@linuxfoundation.org, huawei.libin@huawei.com,
hughd@google.com, jack@suse.cz, jglisse@redhat.com,
jolsa@redhat.com, kan.liang@intel.com,
kirill.shutemov@linux.intel.com, kjlx@templeofstupid.com,
kstewart@linuxfoundation.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
mhocko@suse.com, milian.wolff@kdab.com, mingo@redhat.com,
namhyung@kernel.org, naveen.n.rao@linux.vnet.ibm.com,
pc@us.ibm.com, pombredanne@nexb.com, rostedt@goodmis.org,
tglx@linutronix.de, tmricht@linux.vnet.ibm.com,
willy@infradead.org, yao.jin@linux.intel.com,
fengguang.wu@intel.com
Subject: Re: [PATCH 6/8] trace_uprobe/sdt: Fix multiple update of same reference counter
Date: Mon, 19 Mar 2018 14:40:51 +0100 [thread overview]
Message-ID: <20180319134050.GA12554@redhat.com> (raw)
In-Reply-To: <4b337afd-fc5e-6110-888b-d4fa36a797ee@linux.vnet.ibm.com>
Hi Ravi,
On 03/19, Ravi Bangoria wrote:
>
> On 03/16/2018 11:20 PM, Oleg Nesterov wrote:
> >
> > And it seems that you are trying to confuse yourself, not only me ;) Just
> > suppose that an application does mmap+munmap in a loop and the mapped region
> > contains uprobe but not the counter.
>
> this is fine because ...
Yes, I guess I tried to say "counter but not uprobe" but possibly I was actually
confused.
> Our initial design was to increment counter in install_breakpoint() but
> uprobed instruction gets patched in a very early stage of binary loading
> and vma that holds the counter may not be mapped yet.
Yes, yes, I understand this is not that simple...
> > Btw, why do we need a counter, not a boolean? Who else can modify it?
> > Or different uprobes can share the same counter?
>
> Yes, multiple SDT markers can share the counter.
OK, thanks.
Oleg.
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WARNING: multiple messages have this Message-ID (diff)
From: Oleg Nesterov <oleg@redhat.com>
To: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: mhiramat@kernel.org, peterz@infradead.org,
srikar@linux.vnet.ibm.com, acme@kernel.org,
ananth@linux.vnet.ibm.com, akpm@linux-foundation.org,
alexander.shishkin@linux.intel.com, alexis.berlemont@gmail.com,
corbet@lwn.net, dan.j.williams@intel.com,
gregkh@linuxfoundation.org, huawei.libin@huawei.com,
hughd@google.com, jack@suse.cz, jglisse@redhat.com,
jolsa@redhat.com, kan.liang@intel.com,
kirill.shutemov@linux.intel.com, kjlx@templeofstupid.com,
kstewart@linuxfoundation.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
mhocko@suse.com, milian.wolff@kdab.com, mingo@redhat.com,
namhyung@kernel.org, naveen.n.rao@linux.vnet.ibm.com,
pc@us.ibm.com, pombredanne@nexb.com, rostedt@goodmis.org,
tglx@linutronix.de, tmricht@linux.vnet.ibm.com,
willy@infradead.org, yao.jin@linux.intel.com,
fengguang.wu@intel.com
Subject: Re: [PATCH 6/8] trace_uprobe/sdt: Fix multiple update of same reference counter
Date: Mon, 19 Mar 2018 14:40:51 +0100 [thread overview]
Message-ID: <20180319134050.GA12554@redhat.com> (raw)
In-Reply-To: <4b337afd-fc5e-6110-888b-d4fa36a797ee@linux.vnet.ibm.com>
Hi Ravi,
On 03/19, Ravi Bangoria wrote:
>
> On 03/16/2018 11:20 PM, Oleg Nesterov wrote:
> >
> > And it seems that you are trying to confuse yourself, not only me ;) Just
> > suppose that an application does mmap+munmap in a loop and the mapped region
> > contains uprobe but not the counter.
>
> this is fine because ...
Yes, I guess I tried to say "counter but not uprobe" but possibly I was actually
confused.
> Our initial design was to increment counter in install_breakpoint() but
> uprobed instruction gets patched in a very early stage of binary loading
> and vma that holds the counter may not be mapped yet.
Yes, yes, I understand this is not that simple...
> > Btw, why do we need a counter, not a boolean? Who else can modify it?
> > Or different uprobes can share the same counter?
>
> Yes, multiple SDT markers can share the counter.
OK, thanks.
Oleg.
next prev parent reply other threads:[~2018-03-19 13:41 UTC|newest]
Thread overview: 116+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-13 12:55 [PATCH 0/8] trace_uprobe: Support SDT markers having reference count (semaphore) Ravi Bangoria
2018-03-13 12:55 ` Ravi Bangoria
2018-03-13 12:55 ` [PATCH 1/8] Uprobe: Export vaddr <-> offset conversion functions Ravi Bangoria
2018-03-13 12:55 ` Ravi Bangoria
2018-03-13 20:36 ` Jerome Glisse
2018-03-13 20:36 ` Jerome Glisse
2018-03-13 20:36 ` Jerome Glisse
2018-03-15 16:27 ` Steven Rostedt
2018-03-15 16:27 ` Steven Rostedt
2018-03-16 8:54 ` Ravi Bangoria
2018-03-16 8:54 ` Ravi Bangoria
2018-03-13 12:55 ` [PATCH 2/8] mm: Prefix vma_ to vaddr_to_offset() and offset_to_vaddr() Ravi Bangoria
2018-03-13 12:55 ` Ravi Bangoria
2018-03-13 20:38 ` Jerome Glisse
2018-03-13 20:38 ` Jerome Glisse
2018-03-13 20:38 ` Jerome Glisse
2018-03-15 16:28 ` Steven Rostedt
2018-03-15 16:28 ` Steven Rostedt
2018-03-16 8:58 ` Ravi Bangoria
2018-03-16 8:58 ` Ravi Bangoria
2018-03-13 12:55 ` [PATCH 3/8] Uprobe: Rename map_info to uprobe_map_info Ravi Bangoria
2018-03-13 12:55 ` Ravi Bangoria
2018-03-13 20:39 ` Jerome Glisse
2018-03-13 20:39 ` Jerome Glisse
2018-03-13 20:39 ` Jerome Glisse
2018-03-15 16:44 ` Steven Rostedt
2018-03-15 16:44 ` Steven Rostedt
2018-03-16 8:56 ` Ravi Bangoria
2018-03-16 8:56 ` Ravi Bangoria
2018-03-13 12:55 ` [PATCH 4/8] Uprobe: Export uprobe_map_info along with uprobe_{build/free}_map_info() Ravi Bangoria
2018-03-13 12:55 ` Ravi Bangoria
2018-03-13 20:40 ` Jerome Glisse
2018-03-13 20:40 ` Jerome Glisse
2018-03-13 20:40 ` Jerome Glisse
2018-03-15 16:32 ` Steven Rostedt
2018-03-15 16:32 ` Steven Rostedt
2018-03-16 8:59 ` Ravi Bangoria
2018-03-16 8:59 ` Ravi Bangoria
2018-03-13 12:56 ` [PATCH 5/8] trace_uprobe: Support SDT markers having reference count (semaphore) Ravi Bangoria
2018-03-13 12:56 ` Ravi Bangoria
2018-03-14 13:48 ` Masami Hiramatsu
2018-03-14 13:48 ` Masami Hiramatsu
2018-03-14 15:12 ` Ravi Bangoria
2018-03-14 15:12 ` Ravi Bangoria
2018-03-14 16:59 ` Oleg Nesterov
2018-03-14 16:59 ` Oleg Nesterov
2018-03-15 11:23 ` Ravi Bangoria
2018-03-15 11:23 ` Ravi Bangoria
2018-03-19 4:28 ` Ravi Bangoria
2018-03-19 4:28 ` Ravi Bangoria
2018-03-19 13:46 ` Oleg Nesterov
2018-03-19 13:46 ` Oleg Nesterov
2018-03-14 21:58 ` Steven Rostedt
2018-03-14 21:58 ` Steven Rostedt
2018-03-15 14:21 ` Oleg Nesterov
2018-03-15 14:21 ` Oleg Nesterov
2018-03-15 14:30 ` Oleg Nesterov
2018-03-15 14:30 ` Oleg Nesterov
2018-03-16 9:28 ` Ravi Bangoria
2018-03-16 9:28 ` Ravi Bangoria
2018-03-16 11:39 ` Oleg Nesterov
2018-03-16 11:39 ` Oleg Nesterov
2018-03-16 11:46 ` Ravi Bangoria
2018-03-16 11:46 ` Ravi Bangoria
2018-03-16 9:21 ` Ravi Bangoria
2018-03-16 9:21 ` Ravi Bangoria
2018-03-15 15:01 ` Oleg Nesterov
2018-03-15 15:01 ` Oleg Nesterov
2018-03-16 9:31 ` Ravi Bangoria
2018-03-16 9:31 ` Ravi Bangoria
2018-03-15 16:48 ` Steven Rostedt
2018-03-15 16:48 ` Steven Rostedt
2018-03-16 9:01 ` Ravi Bangoria
2018-03-16 9:01 ` Ravi Bangoria
2018-03-16 16:16 ` Oleg Nesterov
2018-03-16 16:16 ` Oleg Nesterov
2018-03-13 12:56 ` [PATCH 6/8] trace_uprobe/sdt: Fix multiple update of same reference counter Ravi Bangoria
2018-03-13 12:56 ` Ravi Bangoria
2018-03-14 14:15 ` Masami Hiramatsu
2018-03-14 14:15 ` Masami Hiramatsu
2018-03-14 15:15 ` Ravi Bangoria
2018-03-14 15:15 ` Ravi Bangoria
2018-03-15 14:49 ` Oleg Nesterov
2018-03-15 14:49 ` Oleg Nesterov
2018-03-16 12:12 ` Ravi Bangoria
2018-03-16 12:12 ` Ravi Bangoria
2018-03-16 12:12 ` Ravi Bangoria
2018-03-16 13:49 ` Ravi Bangoria
2018-03-16 13:49 ` Ravi Bangoria
2018-03-16 13:49 ` Ravi Bangoria
2018-03-16 17:50 ` Oleg Nesterov
2018-03-16 17:50 ` Oleg Nesterov
2018-03-16 17:50 ` Oleg Nesterov
2018-03-19 9:18 ` Ravi Bangoria
2018-03-19 9:18 ` Ravi Bangoria
2018-03-19 9:18 ` Ravi Bangoria
2018-03-19 13:40 ` Oleg Nesterov [this message]
2018-03-19 13:40 ` Oleg Nesterov
2018-03-13 12:56 ` [PATCH 7/8] perf probe: Support SDT markers having reference counter (semaphore) Ravi Bangoria
2018-03-13 12:56 ` Ravi Bangoria
2018-03-14 14:09 ` Masami Hiramatsu
2018-03-14 14:09 ` Masami Hiramatsu
2018-03-14 15:21 ` Ravi Bangoria
2018-03-14 15:21 ` Ravi Bangoria
2018-03-13 12:56 ` [PATCH 8/8] trace_uprobe/sdt: Document about reference counter Ravi Bangoria
2018-03-13 12:56 ` Ravi Bangoria
2018-03-14 13:50 ` Masami Hiramatsu
2018-03-14 13:50 ` Masami Hiramatsu
2018-03-14 15:22 ` Ravi Bangoria
2018-03-14 15:22 ` Ravi Bangoria
2018-03-15 12:47 ` Masami Hiramatsu
2018-03-15 12:47 ` Masami Hiramatsu
2018-03-16 9:42 ` Ravi Bangoria
2018-03-16 9:42 ` Ravi Bangoria
2018-03-16 14:26 ` Masami Hiramatsu
2018-03-16 14:26 ` Masami Hiramatsu
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