[PATCH AUTOSEL 5.7 57/61] ceph: do not access the kiocb after aio requests
From: Sasha Levin <sashal@kernel.org>
Date: 2020-08-21 17:12:05
Also in:
ceph-devel, lkml
Subsystem:
ceph distributed file system client (ceph), filesystems (vfs and infrastructure), the rest · Maintainers:
Ilya Dryomov, Alex Markuze, Viacheslav Dubeyko, Alexander Viro, Christian Brauner, Linus Torvalds
From: Xiubo Li <redacted> [ 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 <redacted> Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org> --- 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 afdfca965a7fc..599eca249973d 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c@@ -1508,6 +1508,7 @@ 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;
@@ -1516,7 +1517,7 @@ static ssize_t ceph_read_iter(struct kiocb *iocb, struct iov_iter *to) 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);
@@ -1573,7 +1574,7 @@ static ssize_t ceph_read_iter(struct kiocb *iocb, struct iov_iter *to) } 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