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Commit 20cbc972 authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds
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Fix clear_refs_write() use of struct mm_walk 



Don't use a static entry, so as to prevent races during concurrent use
of this function.

Reported-by: default avatarAlexey Dobriyan <adobriyan@gmail.com>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent fbe08257

fs/proc/task_mmu.c

+4 −4
Original line number Diff line number Diff line
@@ -476,10 +476,10 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf, 
		return -ESRCH;

	mm = get_task_mm(task);

	if (mm) {

		static struct mm_walk clear_refs_walk;

		memset(&clear_refs_walk, 0, sizeof(clear_refs_walk));

		clear_refs_walk.pmd_entry = clear_refs_pte_range;

		clear_refs_walk.mm = mm;

		struct mm_walk clear_refs_walk = {

			.pmd_entry = clear_refs_pte_range,

			.mm = mm,

		};

		down_read(&mm->mmap_sem);

		for (vma = mm->mmap; vma; vma = vma->vm_next) {

			clear_refs_walk.private = vma;