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Commit 0d5f5f45 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
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fs/proc/task_mmu.c: shift "priv->task = NULL" from m_start() to m_stop() 



1. There is no reason to reset ->tail_vma in m_start(), if we return
   IS_ERR_OR_NULL() it won't be used.

2. m_start() also clears priv->task to ensure that m_stop() won't use
   the stale pointer if we fail before get_task_struct(). But this is
   ugly and confusing, move this initialization in m_stop().

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: default avatarCyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 23d54837

fs/proc/task_mmu.c

+3 −6
Original line number Original line Diff line number Diff line
@@ -146,17 +146,12 @@ static void *m_start(struct seq_file *m, loff_t *pos) 
	struct vm_area_struct *vma, *tail_vma = NULL;

	struct vm_area_struct *vma, *tail_vma = NULL;

	loff_t l = *pos;

	loff_t l = *pos;





	/* Clear the per syscall fields in priv */

	priv->task = NULL;

	priv->tail_vma = NULL;



	/*

	/*

	 * We remember last_addr rather than next_addr to hit with

	 * We remember last_addr rather than next_addr to hit with

	 * vmacache most of the time. We have zero last_addr at

	 * vmacache most of the time. We have zero last_addr at

	 * the beginning and also after lseek. We will have -1 last_addr

	 * the beginning and also after lseek. We will have -1 last_addr

	 * after the end of the vmas.

	 * after the end of the vmas.

	 */

	 */



	if (last_addr == -1UL)

	if (last_addr == -1UL)

		return NULL;

		return NULL;
@@ -228,8 +223,10 @@ static void m_stop(struct seq_file *m, void *v) 




	if (!IS_ERR_OR_NULL(v))

	if (!IS_ERR_OR_NULL(v))

		vma_stop(priv);

		vma_stop(priv);

	if (priv->task)

	if (priv->task) {

		put_task_struct(priv->task);

		put_task_struct(priv->task);

		priv->task = NULL;

	}

}

}





static int proc_maps_open(struct inode *inode, struct file *file,

static int proc_maps_open(struct inode *inode, struct file *file,