linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
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 5/8] trace_uprobe: Support SDT markers having reference count (semaphore)
Date: Fri, 16 Mar 2018 12:39:18 +0100	[thread overview]
Message-ID: <20180316113917.GA21303@redhat.com> (raw)
In-Reply-To: <3b303a2d-35dd-9178-fc03-de9f2d588797@linux.vnet.ibm.com>

On 03/16, Ravi Bangoria wrote:
>
> On 03/15/2018 08:00 PM, Oleg Nesterov wrote:
> > Note to mention that sdt_find_vma() can return NULL but the callers do
> > vma_offset_to_vaddr(vma) without any check.
>
> If the "mm" we are passing to sdt_find_vma() is returned by
> uprobe_build_map_info(ref_ctr_offset), sdt_find_vma() must
> _not_ return NULL.

Not at all.

Once build_map_info() returns any mapping can go away. Otherwise, why do
you think the caller has to take ->mmap_sem and use find_vma()? If you
were right, build_map_info() could just return the list of vma's instead
of list of mm's.

Oleg.

  reply	other threads:[~2018-03-16 11:39 UTC|newest]

Thread overview: 54+ 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 ` [PATCH 1/8] Uprobe: Export vaddr <-> offset conversion functions Ravi Bangoria
2018-03-13 20:36   ` Jerome Glisse
2018-03-15 16:27   ` Steven Rostedt
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 20:38   ` Jerome Glisse
2018-03-15 16:28   ` Steven Rostedt
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 20:39   ` Jerome Glisse
2018-03-15 16:44   ` Steven Rostedt
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 20:40   ` Jerome Glisse
2018-03-15 16:32   ` Steven Rostedt
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
2018-03-14 13:48   ` Masami Hiramatsu
2018-03-14 15:12     ` Ravi Bangoria
2018-03-14 16:59   ` Oleg Nesterov
2018-03-15 11:23     ` Ravi Bangoria
2018-03-19  4:28     ` Ravi Bangoria
2018-03-19 13:46       ` Oleg Nesterov
2018-03-14 21:58   ` Steven Rostedt
2018-03-15 14:21   ` Oleg Nesterov
2018-03-15 14:30     ` Oleg Nesterov
2018-03-16  9:28       ` Ravi Bangoria
2018-03-16 11:39         ` Oleg Nesterov [this message]
2018-03-16 11:46           ` Ravi Bangoria
2018-03-16  9:21     ` Ravi Bangoria
2018-03-15 15:01   ` Oleg Nesterov
2018-03-16  9:31     ` Ravi Bangoria
2018-03-15 16:48   ` Steven Rostedt
2018-03-16  9:01     ` Ravi Bangoria
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
2018-03-14 14:15   ` Masami Hiramatsu
2018-03-14 15:15     ` Ravi Bangoria
2018-03-15 14:49   ` Oleg Nesterov
2018-03-16 12:12     ` Ravi Bangoria
2018-03-16 13:49       ` Ravi Bangoria
2018-03-16 17:50       ` Oleg Nesterov
2018-03-19  9:18         ` Ravi Bangoria
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
2018-03-14 14:09   ` Masami Hiramatsu
2018-03-14 15:21     ` Ravi Bangoria
2018-03-13 12:56 ` [PATCH 8/8] trace_uprobe/sdt: Document about reference counter Ravi Bangoria
2018-03-14 13:50   ` Masami Hiramatsu
2018-03-14 15:22     ` Ravi Bangoria
2018-03-15 12:47       ` Masami Hiramatsu
2018-03-16  9:42         ` Ravi Bangoria
2018-03-16 14:26           ` Masami Hiramatsu

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20180316113917.GA21303@redhat.com \
    --to=oleg@redhat.com \
    --cc=acme@kernel.org \
    --cc=akpm@linux-foundation.org \
    --cc=alexander.shishkin@linux.intel.com \
    --cc=alexis.berlemont@gmail.com \
    --cc=ananth@linux.vnet.ibm.com \
    --cc=corbet@lwn.net \
    --cc=dan.j.williams@intel.com \
    --cc=fengguang.wu@intel.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=huawei.libin@huawei.com \
    --cc=hughd@google.com \
    --cc=jack@suse.cz \
    --cc=jglisse@redhat.com \
    --cc=jolsa@redhat.com \
    --cc=kan.liang@intel.com \
    --cc=kirill.shutemov@linux.intel.com \
    --cc=kjlx@templeofstupid.com \
    --cc=kstewart@linuxfoundation.org \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mhiramat@kernel.org \
    --cc=mhocko@suse.com \
    --cc=milian.wolff@kdab.com \
    --cc=mingo@redhat.com \
    --cc=namhyung@kernel.org \
    --cc=naveen.n.rao@linux.vnet.ibm.com \
    --cc=pc@us.ibm.com \
    --cc=peterz@infradead.org \
    --cc=pombredanne@nexb.com \
    --cc=ravi.bangoria@linux.vnet.ibm.com \
    --cc=rostedt@goodmis.org \
    --cc=srikar@linux.vnet.ibm.com \
    --cc=tglx@linutronix.de \
    --cc=tmricht@linux.vnet.ibm.com \
    --cc=willy@infradead.org \
    --cc=yao.jin@linux.intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).