From: Andi Kleen <andi@firstfloor.org>
To: Stefani Seibold <stefani@seibold.net>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Americo Wang <xiyou.wangcong@gmail.com>
Subject: Re: [PATCH] update fix X86_64 procfs provide stack information for threads
Date: Wed, 04 Nov 2009 12:17:52 +0100 [thread overview]
Message-ID: <874opaa68v.fsf@basil.nowhere.org> (raw)
In-Reply-To: <1257233486.22553.6.camel@wall-e> (Stefani Seibold's message of "Tue, 03 Nov 2009 08:31:26 +0100")
Stefani Seibold <stefani@seibold.net> writes:
>
> +#ifdef CONFIG_IA32_EMULATION
> +unsigned long KSTK_ESP(struct task_struct *task)
> +{
> + return (test_tsk_thread_flag(task, TIF_IA32)) ? \
> + (task_pt_regs(task)->sp) : \
> + ((task)->thread.usersp);
Usersp is only set for system calls, but not when the process is blocked
in a interrupt.
In general if you really want a reliable implementation of this
you would really need to stop the task and grab the stack pointer;
otherwise it can be arbitarily outdated anyways.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2009-11-04 11:17 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-03 7:31 [PATCH] update fix X86_64 procfs provide stack information for threads Stefani Seibold
2009-11-03 8:28 ` Ingo Molnar
2009-11-03 9:06 ` Stefani Seibold
2009-11-03 18:16 ` Ingo Molnar
2009-11-05 8:19 ` [PATCH] RFC x86_64 more accurate KSTK_ESP implementation Stefani Seibold
2009-11-05 11:08 ` Andi Kleen
2009-11-05 12:11 ` Stefani Seibold
2009-11-08 11:35 ` Ingo Molnar
2009-11-08 12:51 ` Stefani Seibold
2009-11-08 12:55 ` Ingo Molnar
2009-11-08 14:00 ` Stefani Seibold
2009-11-08 16:34 ` H. Peter Anvin
2009-11-08 19:37 ` Andi Kleen
2009-11-05 13:02 ` [PATCH] fix /proc/<pid>/stat stack pointer for kernel threads Stefani Seibold
2009-11-13 8:01 ` [tip:x86/urgent] fs: " Stefani Seibold
2009-11-04 11:17 ` Andi Kleen [this message]
2009-11-04 11:50 ` [PATCH] update fix X86_64 procfs provide stack information for threads Stefani Seibold
2009-11-04 12:00 ` Andi Kleen
2009-11-04 12:22 ` Stefani Seibold
2009-11-04 15:42 ` Stefani Seibold
2009-11-04 22:21 ` Stefani Seibold
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