Commit 0d5f5f45 authored Oct 09, 2014 by Oleg Nesterov Committed by Linus Torvalds Oct 09, 2014

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: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 23d54837

fs/proc/task_mmu.c

+3 −6

Original line number	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;
		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
		* vmacache most of the time. We have zero last_addr at
		* the beginning and also after lseek. We will have -1 last_addr
		* after the end of the vmas.
		*/

		if (last_addr == -1UL)
		return NULL;

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

		if (!IS_ERR_OR_NULL(v))
		vma_stop(priv);
		if (priv->task)
		if (priv->task) {
		put_task_struct(priv->task);
		priv->task = NULL;
		}
		}

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

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