 3bbfe05967
			
		
	
	
	3bbfe05967
	
	
	
		
			
			After commit 831830b5a2 aka
"restrict reading from /proc/<pid>/maps to those who share ->mm or can ptrace"
sysctl stopped being relevant because commit moved security checks from ->show
time to ->start time (mm_for_maps()).
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Kees Cook <kees.cook@canonical.com>
		
	
			
		
			
				
	
	
		
			195 lines
		
	
	
	
		
			4.3 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			195 lines
		
	
	
	
		
			4.3 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
| 
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| #include <linux/mm.h>
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| #include <linux/file.h>
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| #include <linux/fdtable.h>
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| #include <linux/mount.h>
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| #include <linux/ptrace.h>
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| #include <linux/seq_file.h>
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| #include "internal.h"
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| 
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| /*
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|  * Logic: we've got two memory sums for each process, "shared", and
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|  * "non-shared". Shared memory may get counted more then once, for
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|  * each process that owns it. Non-shared memory is counted
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|  * accurately.
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|  */
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| void task_mem(struct seq_file *m, struct mm_struct *mm)
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| {
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| 	struct vm_list_struct *vml;
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| 	unsigned long bytes = 0, sbytes = 0, slack = 0;
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|         
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| 	down_read(&mm->mmap_sem);
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| 	for (vml = mm->context.vmlist; vml; vml = vml->next) {
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| 		if (!vml->vma)
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| 			continue;
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| 
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| 		bytes += kobjsize(vml);
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| 		if (atomic_read(&mm->mm_count) > 1 ||
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| 		    atomic_read(&vml->vma->vm_usage) > 1
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| 		    ) {
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| 			sbytes += kobjsize((void *) vml->vma->vm_start);
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| 			sbytes += kobjsize(vml->vma);
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| 		} else {
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| 			bytes += kobjsize((void *) vml->vma->vm_start);
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| 			bytes += kobjsize(vml->vma);
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| 			slack += kobjsize((void *) vml->vma->vm_start) -
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| 				(vml->vma->vm_end - vml->vma->vm_start);
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| 		}
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| 	}
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| 
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| 	if (atomic_read(&mm->mm_count) > 1)
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| 		sbytes += kobjsize(mm);
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| 	else
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| 		bytes += kobjsize(mm);
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| 	
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| 	if (current->fs && atomic_read(¤t->fs->count) > 1)
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| 		sbytes += kobjsize(current->fs);
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| 	else
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| 		bytes += kobjsize(current->fs);
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| 
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| 	if (current->files && atomic_read(¤t->files->count) > 1)
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| 		sbytes += kobjsize(current->files);
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| 	else
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| 		bytes += kobjsize(current->files);
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| 
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| 	if (current->sighand && atomic_read(¤t->sighand->count) > 1)
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| 		sbytes += kobjsize(current->sighand);
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| 	else
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| 		bytes += kobjsize(current->sighand);
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| 
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| 	bytes += kobjsize(current); /* includes kernel stack */
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| 
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| 	seq_printf(m,
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| 		"Mem:\t%8lu bytes\n"
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| 		"Slack:\t%8lu bytes\n"
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| 		"Shared:\t%8lu bytes\n",
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| 		bytes, slack, sbytes);
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| 
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| 	up_read(&mm->mmap_sem);
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| }
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| 
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| unsigned long task_vsize(struct mm_struct *mm)
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| {
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| 	struct vm_list_struct *tbp;
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| 	unsigned long vsize = 0;
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| 
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| 	down_read(&mm->mmap_sem);
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| 	for (tbp = mm->context.vmlist; tbp; tbp = tbp->next) {
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| 		if (tbp->vma)
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| 			vsize += kobjsize((void *) tbp->vma->vm_start);
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| 	}
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| 	up_read(&mm->mmap_sem);
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| 	return vsize;
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| }
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| 
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| int task_statm(struct mm_struct *mm, int *shared, int *text,
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| 	       int *data, int *resident)
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| {
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| 	struct vm_list_struct *tbp;
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| 	int size = kobjsize(mm);
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| 
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| 	down_read(&mm->mmap_sem);
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| 	for (tbp = mm->context.vmlist; tbp; tbp = tbp->next) {
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| 		size += kobjsize(tbp);
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| 		if (tbp->vma) {
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| 			size += kobjsize(tbp->vma);
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| 			size += kobjsize((void *) tbp->vma->vm_start);
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| 		}
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| 	}
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| 
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| 	size += (*text = mm->end_code - mm->start_code);
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| 	size += (*data = mm->start_stack - mm->start_data);
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| 	up_read(&mm->mmap_sem);
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| 	*resident = size;
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| 	return size;
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| }
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| 
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| /*
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|  * display mapping lines for a particular process's /proc/pid/maps
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|  */
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| static int show_map(struct seq_file *m, void *_vml)
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| {
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| 	struct vm_list_struct *vml = _vml;
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| 
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| 	return nommu_vma_show(m, vml->vma);
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| }
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| 
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| static void *m_start(struct seq_file *m, loff_t *pos)
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| {
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| 	struct proc_maps_private *priv = m->private;
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| 	struct vm_list_struct *vml;
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| 	struct mm_struct *mm;
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| 	loff_t n = *pos;
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| 
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| 	/* pin the task and mm whilst we play with them */
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| 	priv->task = get_pid_task(priv->pid, PIDTYPE_PID);
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| 	if (!priv->task)
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| 		return NULL;
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| 
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| 	mm = mm_for_maps(priv->task);
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| 	if (!mm) {
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| 		put_task_struct(priv->task);
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| 		priv->task = NULL;
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| 		return NULL;
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| 	}
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| 
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| 	/* start from the Nth VMA */
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| 	for (vml = mm->context.vmlist; vml; vml = vml->next)
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| 		if (n-- == 0)
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| 			return vml;
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| 	return NULL;
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| }
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| 
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| static void m_stop(struct seq_file *m, void *_vml)
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| {
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| 	struct proc_maps_private *priv = m->private;
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| 
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| 	if (priv->task) {
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| 		struct mm_struct *mm = priv->task->mm;
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| 		up_read(&mm->mmap_sem);
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| 		mmput(mm);
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| 		put_task_struct(priv->task);
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| 	}
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| }
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| 
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| static void *m_next(struct seq_file *m, void *_vml, loff_t *pos)
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| {
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| 	struct vm_list_struct *vml = _vml;
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| 
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| 	(*pos)++;
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| 	return vml ? vml->next : NULL;
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| }
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| 
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| static const struct seq_operations proc_pid_maps_ops = {
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| 	.start	= m_start,
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| 	.next	= m_next,
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| 	.stop	= m_stop,
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| 	.show	= show_map
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| };
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| 
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| static int maps_open(struct inode *inode, struct file *file)
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| {
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| 	struct proc_maps_private *priv;
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| 	int ret = -ENOMEM;
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| 
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| 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
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| 	if (priv) {
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| 		priv->pid = proc_pid(inode);
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| 		ret = seq_open(file, &proc_pid_maps_ops);
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| 		if (!ret) {
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| 			struct seq_file *m = file->private_data;
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| 			m->private = priv;
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| 		} else {
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| 			kfree(priv);
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| 		}
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| 	}
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| 	return ret;
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| }
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| 
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| const struct file_operations proc_maps_operations = {
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| 	.open		= maps_open,
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| 	.read		= seq_read,
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| 	.llseek		= seq_lseek,
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| 	.release	= seq_release_private,
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| };
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| 
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