| Message ID | 20230228045459.13524-1-joseph.qi@linux.alibaba.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | io_uring: fix fget leak when fs don't support nowait buffered read | expand |
On Tue, 28 Feb 2023 12:54:59 +0800, Joseph Qi wrote: > Heming reported a BUG when using io_uring doing link-cp on ocfs2. [1] > > Do the following steps can reproduce this BUG: > mount -t ocfs2 /dev/vdc /mnt/ocfs2 > cp testfile /mnt/ocfs2/ > ./link-cp /mnt/ocfs2/testfile /mnt/ocfs2/testfile.1 > umount /mnt/ocfs2 > > [...] Applied, thanks! [1/1] io_uring: fix fget leak when fs don't support nowait buffered read commit: 54aa7f2330b82884f4a1afce0220add6e8312f8b Best regards,
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 1df68da89f99..7ad3b8af2a4b 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -1777,7 +1777,7 @@ int io_req_prep_async(struct io_kiocb *req) const struct io_issue_def *def = &io_issue_defs[req->opcode]; /* assign early for deferred execution for non-fixed file */ - if (def->needs_file && !(req->flags & REQ_F_FIXED_FILE)) + if (def->needs_file && !(req->flags & REQ_F_FIXED_FILE) && !req->file) req->file = io_file_get_normal(req, req->cqe.fd); if (!cdef->prep_async) return 0;
Heming reported a BUG when using io_uring doing link-cp on ocfs2. [1] Do the following steps can reproduce this BUG: mount -t ocfs2 /dev/vdc /mnt/ocfs2 cp testfile /mnt/ocfs2/ ./link-cp /mnt/ocfs2/testfile /mnt/ocfs2/testfile.1 umount /mnt/ocfs2 Then umount will fail, and it outputs: umount: /mnt/ocfs2: target is busy. While tracing umount, it blames mnt_get_count() not return as expected. Do a deep investigation for fget()/fput() on related code flow, I've finally found that fget() leaks since ocfs2 doesn't support nowait buffered read. io_issue_sqe |-io_assign_file // do fget() first |-io_read |-io_iter_do_read |-ocfs2_file_read_iter // return -EOPNOTSUPP |-kiocb_done |-io_rw_done |-__io_complete_rw_common // set REQ_F_REISSUE |-io_resubmit_prep |-io_req_prep_async // override req->file, leak happens This was introduced by commit a196c78b5443 in v5.18. Fix it by don't re-assign req->file if it has already been assigned. [1] https://lore.kernel.org/ocfs2-devel/ab580a75-91c8-d68a-3455-40361be1bfa8@linux.alibaba.com/T/#t Fixes: a196c78b5443 ("io_uring: assign non-fixed early for async work") Cc: <stable@vger.kernel.org> Reported-by: Heming Zhao <heming.zhao@suse.com> Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com> --- io_uring/io_uring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)