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authorYang Shi <yang.shi@linux.alibaba.com>2019-11-15 17:34:33 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-11-15 18:33:59 -0800
commita85dfc305a21acfc48fa28a0fa0a0cb6ad496120 (patch)
treebd307c4fe0aebc190733dbcf3854c5877ec9820c
parent875fef493f21e54d20d71a581687990aaa50268c (diff)
downloadlinux-sh-a85dfc305a21acfc48fa28a0fa0a0cb6ad496120.tar.gz
mm: mempolicy: fix the wrong return value and potential pages leak of mbind
Commit d883544515aa ("mm: mempolicy: make the behavior consistent when MPOL_MF_MOVE* and MPOL_MF_STRICT were specified") fixed the return value of mbind() for a couple of corner cases. But, it altered the errno for some other cases, for example, mbind() should return -EFAULT when part or all of the memory range specified by nodemask and maxnode points outside your accessible address space, or there was an unmapped hole in the specified memory range specified by addr and len. Fix this by preserving the errno returned by queue_pages_range(). And, the pagelist may be not empty even though queue_pages_range() returns error, put the pages back to LRU since mbind_range() is not called to really apply the policy so those pages should not be migrated, this is also the old behavior before the problematic commit. Link: http://lkml.kernel.org/r/1572454731-3925-1-git-send-email-yang.shi@linux.alibaba.com Fixes: d883544515aa ("mm: mempolicy: make the behavior consistent when MPOL_MF_MOVE* and MPOL_MF_STRICT were specified") Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Reported-by: Li Xinhai <lixinhai.lxh@gmail.com> Reviewed-by: Li Xinhai <lixinhai.lxh@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@suse.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: <stable@vger.kernel.org> [4.19 and 5.2+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/mempolicy.c14
1 files changed, 9 insertions, 5 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 4ae967bcf954..e08c94170ae4 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -672,7 +672,9 @@ static const struct mm_walk_ops queue_pages_walk_ops = {
* 1 - there is unmovable page, but MPOL_MF_MOVE* & MPOL_MF_STRICT were
* specified.
* 0 - queue pages successfully or no misplaced page.
- * -EIO - there is misplaced page and only MPOL_MF_STRICT was specified.
+ * errno - i.e. misplaced pages with MPOL_MF_STRICT specified (-EIO) or
+ * memory range specified by nodemask and maxnode points outside
+ * your accessible address space (-EFAULT)
*/
static int
queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end,
@@ -1286,7 +1288,7 @@ static long do_mbind(unsigned long start, unsigned long len,
flags | MPOL_MF_INVERT, &pagelist);
if (ret < 0) {
- err = -EIO;
+ err = ret;
goto up_out;
}
@@ -1305,10 +1307,12 @@ static long do_mbind(unsigned long start, unsigned long len,
if ((ret > 0) || (nr_failed && (flags & MPOL_MF_STRICT)))
err = -EIO;
- } else
- putback_movable_pages(&pagelist);
-
+ } else {
up_out:
+ if (!list_empty(&pagelist))
+ putback_movable_pages(&pagelist);
+ }
+
up_write(&mm->mmap_sem);
mpol_out:
mpol_put(new);