linux-kernel - Re: [PATCH] fix X86_64 procfs provide stack information for threads

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Date:	Tue, 3 Nov 2009 13:58:47 +0800
From:	Américo Wang <xiyou.wangcong@...il.com>
To:	Stefani Seibold <stefani@...bold.net>
Cc:	linux-kernel <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Alexey Dobriyan <adobriyan@...il.com>
Subject: Re: [PATCH] fix X86_64 procfs provide stack information for threads

On Mon, Nov 02, 2009 at 11:47:09AM +0100, Stefani Seibold wrote:
>This patch fix two issues in the procfs stack information on X86_64
>linux. 
>
>The 32 bit loader compat_do_execve did not store stack start (this was
>figured out by alexey).
>
>The stack information on a X64_64 kernel always show 0 kbyte stack
>usage, because of a miss implemented KSTK_ESP macro which always return
>-1. The new implementation returns now the right value. 
>
>The patch is against 2.6.32-rc5-git5.
>
>Andrew would you so kind to apply this patch?
>
>Greetings,
>Stefani
>
>Signed-off-by: Stefani Seibold <stefani@...bold.net>
>---
> arch/x86/include/asm/processor.h |    9 ++++++++-
> arch/x86/kernel/process_64.c     |    8 ++++++++
> fs/compat.c                      |    2 ++
> 3 files changed, 18 insertions(+), 1 deletion(-)
>
>--- linux-2.6.32-rc5/fs/compat.c	2009-10-16 02:41:50.000000000 +0200
>+++ linux-2.6.32-rc5.new/fs/compat.c	2009-11-02 09:00:52.871909633 +0100
>@@ -1532,6 +1532,8 @@
> 	if (retval < 0)
> 		goto out;
> 
>+	current->stack_start = current->mm->start_stack;
>+
> 	/* execve succeeded */
> 	current->fs->in_exec = 0;
> 	current->in_execve = 0;
>--- linux-2.6.32-rc5/arch/x86/include/asm/processor.h	2009-10-16 02:41:50.000000000 +0200
>+++ linux-2.6.32-rc5.new/arch/x86/include/asm/processor.h	2009-11-02 10:39:47.177909657 +0100
>@@ -29,6 +29,7 @@
> #include <linux/threads.h>
> #include <linux/math64.h>
> #include <linux/init.h>
>+//#include <linux/sched.h>

Hey, what is this? :)

Except this, this patch looks fine for me:

Reviewed-by: WANG Cong <xiyou.wangcong@...il.com>

> 
> /*
>  * Default implementation of macro that returns current
>@@ -1000,7 +1001,13 @@
> #define thread_saved_pc(t)	(*(unsigned long *)((t)->thread.sp - 8))
> 
> #define task_pt_regs(tsk)	((struct pt_regs *)(tsk)->thread.sp0 - 1)
>-#define KSTK_ESP(tsk)		-1 /* sorry. doesn't work for syscall. */
>+
>+#ifdef CONFIG_IA32_EMULATION
>+extern unsigned long KSTK_ESP(struct task_struct *task);
>+#else
>+#define KSTK_ESP(task)		((task)->thread.usersp)
>+#endif
>+
> #endif /* CONFIG_X86_64 */
> 
> extern void start_thread(struct pt_regs *regs, unsigned long new_ip,
>--- linux-2.6.32-rc5/arch/x86/kernel/process_64.c	2009-10-16 02:41:50.000000000 +0200
>+++ linux-2.6.32-rc5.new/arch/x86/kernel/process_64.c	2009-11-02 10:48:23.614936810 +0100
>@@ -664,3 +669,11 @@
> 	return do_arch_prctl(current, code, addr);
> }
> 
>+#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);
>+}
>+#endif
>
>
>--
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