From: Xiubo Li <xiubli@xxxxxxxxxx> [ Upstream commit d1d9655052606fd9078e896668ec90191372d513 ] In aio case, if the completion comes very fast just before the ceph_read_iter() returns to fs/aio.c, the kiocb will be freed in the completion callback, then if ceph_read_iter() access again we will potentially hit the use-after-free bug. [ jlayton: initialize direct_lock early, and use it everywhere ] URL: https://tracker.ceph.com/issues/45649 Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- fs/ceph/file.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/ceph/file.c b/fs/ceph/file.c index ce54a1b12819b..4a6b14a2bd7f9 100644 --- a/fs/ceph/file.c +++ b/fs/ceph/file.c @@ -1260,6 +1260,7 @@ static ssize_t ceph_read_iter(struct kiocb *iocb, struct iov_iter *to) struct inode *inode = file_inode(filp); struct ceph_inode_info *ci = ceph_inode(inode); struct page *pinned_page = NULL; + bool direct_lock = iocb->ki_flags & IOCB_DIRECT; ssize_t ret; int want, got = 0; int retry_op = 0, read = 0; @@ -1268,7 +1269,7 @@ again: dout("aio_read %p %llx.%llx %llu~%u trying to get caps on %p\n", inode, ceph_vinop(inode), iocb->ki_pos, (unsigned)len, inode); - if (iocb->ki_flags & IOCB_DIRECT) + if (direct_lock) ceph_start_io_direct(inode); else ceph_start_io_read(inode); @@ -1325,7 +1326,7 @@ again: } ceph_put_cap_refs(ci, got); - if (iocb->ki_flags & IOCB_DIRECT) + if (direct_lock) ceph_end_io_direct(inode); else ceph_end_io_read(inode); -- 2.25.1
