After the call to ->direct_IO the final reference to the file might have
been dropped by aio_complete already, and the call to file_accessed might
cause a use after free.
Instead update the access time before the I/O, similar to how we
update the time stamps before writes.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
mm/filemap.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index 8a287df..2f1175e 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1910,16 +1910,18 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
if (iocb->ki_flags & IOCB_DIRECT) {
struct address_space *mapping = file->f_mapping;
struct inode *inode = mapping->host;
+ struct iov_iter data = *iter;
loff_t size;
size = i_size_read(inode);
retval = filemap_write_and_wait_range(mapping, iocb->ki_pos,
iocb->ki_pos + count - 1);
- if (!retval) {
- struct iov_iter data = *iter;
- retval = mapping->a_ops->direct_IO(iocb, &data);
- }
+ if (retval < 0)
+ goto out;
+ file_accessed(file);
+
+ retval = mapping->a_ops->direct_IO(iocb, &data);
if (retval > 0) {
iocb->ki_pos += retval;
iov_iter_advance(iter, retval);
@@ -1935,10 +1937,8 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
* DAX files, so don't bother trying.
*/
if (retval < 0 || !iov_iter_count(iter) || iocb->ki_pos >= size ||
- IS_DAX(inode)) {
- file_accessed(file);
+ IS_DAX(inode))
goto out;
- }
}
retval = do_generic_file_read(file, &iocb->ki_pos, iter, retval);
--
2.1.4
--
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