Commit 597425df authored by Hugh Dickins's avatar Hugh Dickins Committed by Andrew Morton
Browse files

mm: userfaultfd: add new UFFDIO_POISON ioctl: fix 

Smatch has observed that pte_offset_map_lock() is now allowed to fail, and
then ptl should not be unlocked.  Use -EAGAIN here like elsewhere.

Link: https://lkml.kernel.org/r/bc7bba61-d34f-ad3a-ccf1-c191585ef851@google.com


Signed-off-by: default avatarHugh Dickins <hughd@google.com>
Reviewed-by: default avatarAxel Rasmussen <axelrasmussen@google.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent fc71884a

mm/userfaultfd.c

+4 −0
Original line number Diff line number Diff line
@@ -300,7 +300,10 @@ static int mfill_atomic_pte_poison(pmd_t *dst_pmd, 
	spinlock_t *ptl;



	_dst_pte = make_pte_marker(PTE_MARKER_POISONED);

	ret = -EAGAIN;

	dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl);

	if (!dst_pte)

		goto out;



	if (mfill_file_over_size(dst_vma, dst_addr)) {

		ret = -EFAULT;
@@ -319,6 +322,7 @@ static int mfill_atomic_pte_poison(pmd_t *dst_pmd, 
	ret = 0;

out_unlock:

	pte_unmap_unlock(dst_pte, ptl);

out:

	return ret;

}