linux-kernel - [PATCH 3/4] ia64: kill thread_matches(), unexport ptrace_check

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Date:	Sun, 20 Jan 2013 20:25:47 +0100
From:	Oleg Nesterov <oleg@...hat.com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Dan Carpenter <dan.carpenter@...cle.com>,
	Kernel Security <security@...nel.org>,
	Michael Davidson <md@...gle.com>,
	Suleiman Souhlal <suleiman@...gle.com>,
	Julien Tinnes <jln@...gle.com>,
	Aaron Durbin <adurbin@...gle.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, Tejun Heo <tj@...nel.org>,
	Roland McGrath <roland@...k.frob.com>,
	Tony Luck <tony.luck@...el.com>,
	Fenghua Yu <fenghua.yu@...el.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: [PATCH 3/4] ia64: kill thread_matches(), unexport
	ptrace_check_attach()

arch/ia64/kernel/ptrace.c:thread_matches() has no users since e868a55c
"[IA64] remove find_thread_for_addr()", remove it.

And this allows us to unexport ptrace_check_attach().

Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---
 arch/ia64/kernel/ptrace.c |   27 ---------------------------
 include/linux/ptrace.h    |    1 -
 kernel/ptrace.c           |    2 +-
 3 files changed, 1 insertions(+), 29 deletions(-)

diff --git a/arch/ia64/kernel/ptrace.c b/arch/ia64/kernel/ptrace.c
index 4265ff6..b7a5fff 100644
--- a/arch/ia64/kernel/ptrace.c
+++ b/arch/ia64/kernel/ptrace.c
@@ -672,33 +672,6 @@ ptrace_attach_sync_user_rbs (struct task_struct *child)
 	read_unlock(&tasklist_lock);
 }
 
-static inline int
-thread_matches (struct task_struct *thread, unsigned long addr)
-{
-	unsigned long thread_rbs_end;
-	struct pt_regs *thread_regs;
-
-	if (ptrace_check_attach(thread, 0) < 0)
-		/*
-		 * If the thread is not in an attachable state, we'll
-		 * ignore it.  The net effect is that if ADDR happens
-		 * to overlap with the portion of the thread's
-		 * register backing store that is currently residing
-		 * on the thread's kernel stack, then ptrace() may end
-		 * up accessing a stale value.  But if the thread
-		 * isn't stopped, that's a problem anyhow, so we're
-		 * doing as well as we can...
-		 */
-		return 0;
-
-	thread_regs = task_pt_regs(thread);
-	thread_rbs_end = ia64_get_user_rbs_end(thread, thread_regs, NULL);
-	if (!on_kernel_rbs(addr, thread_regs->ar_bspstore, thread_rbs_end))
-		return 0;
-
-	return 1;	/* looks like we've got a winner */
-}
-
 /*
  * Write f32-f127 back to task->thread.fph if it has been modified.
  */
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 1693775..89573a3 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -45,7 +45,6 @@ extern long arch_ptrace(struct task_struct *child, long request,
 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
 extern void ptrace_disable(struct task_struct *);
-extern int ptrace_check_attach(struct task_struct *task, bool ignore_state);
 extern int ptrace_request(struct task_struct *child, long request,
 			  unsigned long addr, unsigned long data);
 extern void ptrace_notify(int exit_code);
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 425ff24..6cfa950 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -174,7 +174,7 @@ static void ptrace_unfreeze_traced(struct task_struct *task)
  * RETURNS:
  * 0 on success, -ESRCH if %child is not ready.
  */
-int ptrace_check_attach(struct task_struct *child, bool ignore_state)
+static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
 {
 	int ret = -ESRCH;
 
-- 
1.5.5.1


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