https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=165351

diff --git a/fs/proc/base.c b/fs/proc/base.c
index a3a3eec..3f262cd 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -408,6 +408,26 @@ static int proc_task_root_link(struct in
 	 (task->state == TASK_STOPPED || task->state == TASK_TRACED) && \
 	 security_ptrace(current,task) == 0))
 
+struct mm_struct *mm_for_maps(struct task_struct *task)
+{
+	struct mm_struct *mm = get_task_mm(task);
+	if (!mm)
+		return NULL;
+	down_read(&mm->mmap_sem);
+	task_lock(task);
+	if (task->mm != mm)
+		goto out;
+	if (task->mm != current->mm && tracehook_allow_access_process_vm(task))
+		goto out;
+	task_unlock(task);
+	return mm;
+out:
+	task_unlock(task);
+	up_read(&mm->mmap_sem);
+	mmput(mm);
+	return NULL;
+}
+
 static int proc_pid_environ(struct task_struct *task, char * buffer)
 {
 	int res = 0;
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 0502f17..cd172ce 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -16,6 +16,8 @@ struct vmalloc_info {
 	unsigned long	largest_chunk;
 };
 
+extern struct mm_struct *mm_for_maps(struct task_struct *);
+
 #ifdef CONFIG_MMU
 #define VMALLOC_TOTAL (VMALLOC_END - VMALLOC_START)
 extern void get_vmalloc_info(struct vmalloc_info *vmi);
--- linux-2.6.17.noarch/fs/proc/task_mmu.c~	2006-06-26 19:16:06.064089000 -0400
+++ linux-2.6.17.noarch/fs/proc/task_mmu.c	2006-06-26 19:19:02.178798000 -0400
@@ -344,12 +344,11 @@ static void *m_start(struct seq_file *m,
 	if (!priv->task)
 		return NULL;
 
-	mm = get_task_mm(priv->task);
+	mm = mm_for_maps(priv->task);
 	if (!mm)
 		return NULL;
 
 	priv->tail_vma = tail_vma = get_gate_vma(priv->task);
-	down_read(&mm->mmap_sem);
 
 	/* Start with last addr hint */
 	if (last_addr && (vma = find_vma(mm, last_addr))) {
Date: Mon, 2 Oct 2006 12:10:07 -0400
From: Alexander Viro <aviro@redhat.com>
Subject: [RHEL5 patch] bz #208589 fix

	Patch fixing the breakage in /proc/*/smaps access control
follows.

diff -urN linux-2.6.18.x86_64/fs/proc/base.c foo/fs/proc/base.c
--- linux-2.6.18.x86_64/fs/proc/base.c	2006-09-29 07:30:57.000000000 -0400
+++ foo/fs/proc/base.c	2006-09-29 08:06:52.000000000 -0400
@@ -415,7 +415,7 @@
 	task_lock(task);
 	if (task->mm != mm)
 		goto out;
-	if (task->mm != current->mm && tracehook_allow_access_process_vm(task))
+	if (task->mm != current->mm && __ptrace_may_attach(task) < 0)
 		goto out;
 	task_unlock(task);
 	return mm;
diff -urN linux-2.6.18.x86_64/include/linux/ptrace.h foo/include/linux/ptrace.h
--- linux-2.6.18.x86_64/include/linux/ptrace.h	2006-09-29 07:30:56.000000000 -0400
+++ foo/include/linux/ptrace.h	2006-09-29 08:05:09.000000000 -0400
@@ -57,6 +57,7 @@
 
 
 extern int ptrace_may_attach(struct task_struct *task);
+extern int __ptrace_may_attach(struct task_struct *task);
 
 
 #ifdef CONFIG_PTRACE
diff -urN linux-2.6.18.x86_64/kernel/ptrace.c foo/kernel/ptrace.c
--- linux-2.6.18.x86_64/kernel/ptrace.c	2006-09-29 07:30:56.000000000 -0400
+++ foo/kernel/ptrace.c	2006-09-29 08:04:23.000000000 -0400
@@ -32,7 +32,7 @@
 
 //#define PTRACE_DEBUG
 
-static int may_attach(struct task_struct *task)
+int __ptrace_may_attach(struct task_struct *task)
 {
 	/* May we inspect the given task?
 	 * This check is used both for attaching with ptrace
@@ -66,7 +66,7 @@
 {
 	int err;
 	task_lock(task);
-	err = may_attach(task);
+	err = __ptrace_may_attach(task);
 	task_unlock(task);
 	return !err;
 }