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由 Carsten Otte 提交于
Fix do_wp_page for VM_MIXEDMAP mappings. In the case where pfn_valid returns 0 for a pfn at the beginning of do_wp_page and the mapping is not shared writable, the code branches to label `gotten:' with old_page == NULL. In case the vma is locked (vma->vm_flags & VM_LOCKED), lock_page, clear_page_mlock, and unlock_page try to access the old_page. This patch checks whether old_page is valid before it is dereferenced. The regression was introduced by "mlock: mlocked pages are unevictable" (commit b291f000). Signed-off-by: NCarsten Otte <cotte@de.ibm.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: <stable@kernel.org> [2.6.28.x] Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
ab92661d