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authorAl Viro <viro@zeniv.linux.org.uk>2017-05-08 13:54:47 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2017-05-08 13:54:47 -0400
commit5b47d59af68a8735e4637bacedcb4baf6f47c73f (patch)
treeca26a750a251a2d70c9c3f1616aa58f0c1c3c46d /mm/filemap.c
parenta6a5993243550b09f620941dea741b7421fdf79c (diff)
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fix braino in generic_file_read_iter()
Wrong sign of iov_iter_revert() argument. Unfortunately, slipped through the testing, since most of the time we don't do anything to the iterator afterwards and potential oops on walking the iter->iov too far backwards is too infrequent to be easily triggered. Add a sanity check in iov_iter_revert() to catch bugs like this one; fortunately, the same braino hadn't happened in other callers, but we'd better have a warning if such thing crops up. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index cc480c07c71b..d6e67be1802e 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2048,7 +2048,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
iocb->ki_pos += retval;
count -= retval;
}
- iov_iter_revert(iter, iov_iter_count(iter) - count);
+ iov_iter_revert(iter, count - iov_iter_count(iter));
/*
* Btrfs can have a short DIO read if we encounter