From: Siddhesh Poyarekar <siddhesh.poyarekar@gmail.com>
To: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Alexander Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org, Jamie Lokier <jamie@shareable.org>,
vapier@gentoo.org, Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] Mark thread stack correctly in proc/<pid>/maps
Date: Fri, 24 Feb 2012 10:59:03 +0530 [thread overview]
Message-ID: <CAAHN_R2Awa5X3B09541grAPLkm9RzL9DnixUKFJXpz=1ZkPTFg@mail.gmail.com> (raw)
In-Reply-To: <CAHGf_=oi8_s0Bxn4qSD7S_FBSgp29BPXor4hCf5-kekGnf3qEw@mail.gmail.com>
On Fri, Feb 24, 2012 at 4:47 AM, KOSAKI Motohiro
<kosaki.motohiro@gmail.com> wrote:
> How protect this loop from task exiting? AFAIK, while_each_thread
> require rcu_read_lock or task_list_lock.
I missed this, thanks. I'll send a patch for this on top of my earlier
patch since Andrew has already included the earlier patch.
> Sigh. No, I missed one thing. If application use
> makecontext()/swapcontext() pair,
> ESP is not reliable way to detect pthread stack. At that time the
> stack is still marked
> as anonymous memory.
This is not wrong, because it essentially gives the correct picture of
the state of that task -- the task is using another vma as a stack
during that point and not the one it was allotted by pthreads during
thread creation.
I don't think we can successfully stick to the idea of trying to mark
stack space allocated by pthreads but not used by any task *currently*
as stack as long as the allocation happens outside the kernel space.
The only way to mark this is either by marking the stack as
VM_GROWSDOWN (which will make the stack grow and break some pthreads
functions) or create a new flag, which a simple display such as this
does not deserve. So it's best that this sticks to what the kernel
*knows* is being used as stack.
--
Siddhesh Poyarekar
http://siddhesh.in
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next prev parent reply other threads:[~2012-02-24 5:29 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-14 12:35 Siddhesh Poyarekar
2012-01-16 11:28 ` Jamie Lokier
2012-01-16 13:08 ` Siddhesh Poyarekar
2012-01-16 16:31 ` Jamie Lokier
2012-01-16 17:01 ` Siddhesh Poyarekar
2012-01-17 4:54 ` Siddhesh Poyarekar
2012-02-02 6:24 ` [RESEND][PATCH] " Siddhesh Poyarekar
2012-02-02 21:40 ` KOSAKI Motohiro
2012-02-03 7:09 ` Siddhesh Poyarekar
2012-02-03 8:01 ` KOSAKI Motohiro
2012-02-03 9:49 ` Siddhesh Poyarekar
2012-02-03 10:29 ` Mike Frysinger
2012-02-03 18:34 ` Siddhesh Poyarekar
2012-02-08 4:00 ` Siddhesh Poyarekar
2012-02-08 17:57 ` KOSAKI Motohiro
2012-02-11 10:19 ` Siddhesh Poyarekar
2012-02-11 15:03 ` [PATCH] " Siddhesh Poyarekar
2012-02-21 4:24 ` [RESEND][PATCH] " Siddhesh Poyarekar
2012-02-22 23:00 ` Andrew Morton
2012-02-23 4:03 ` [PATCH] " Siddhesh Poyarekar
2012-02-23 20:22 ` Andrew Morton
2012-02-24 13:05 ` Siddhesh Poyarekar
2012-02-23 23:47 ` Mike Frysinger
2012-02-24 5:47 ` Siddhesh Poyarekar
2012-02-24 16:12 ` Mike Frysinger
2012-02-24 18:23 ` Siddhesh Poyarekar
2012-02-23 23:17 ` KOSAKI Motohiro
2012-02-24 0:49 ` KOSAKI Motohiro
2012-02-24 5:29 ` Siddhesh Poyarekar [this message]
2012-02-24 16:14 ` KOSAKI Motohiro
2012-02-24 18:58 ` Siddhesh Poyarekar
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