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io_uring: fix double prep iovec leak 

Requests may be prepared multiple times with ->io allocated (i.e. async
prepared). Preparation functions don't handle it and forget about
previously allocated resources. This may happen in case of:
- spurious defer_check
- non-head (i.e. async prepared) request executed in sync (via nxt).

Make the handlers check, whether they already allocated resources, which
is true IFF REQ_F_NEED_CLEANUP is set.

Cc: stable@vger.kernel.org # 5.5
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
alistair/sensors
Pavel Begunkov 2020-02-08 13:28:02 +03:00 committed by Jens Axboe
parent a93b33312f
commit 5f798beaf3
1 changed files with 10 additions and 2 deletions
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12
fs/io_uring.c
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@ -2205,7 +2205,8 @@ static int io_read_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
if (unlikely(!(req->file->f_mode & FMODE_READ)))
return -EBADF;
if (!req->io)
/* either don't need iovec imported or already have it */
if (!req->io || req->flags & REQ_F_NEED_CLEANUP)
return 0;
io = req->io;
@ -2293,7 +2294,8 @@ static int io_write_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
if (unlikely(!(req->file->f_mode & FMODE_WRITE)))
return -EBADF;
if (!req->io)
/* either don't need iovec imported or already have it */
if (!req->io || req->flags & REQ_F_NEED_CLEANUP)
return 0;
io = req->io;
@ -2993,6 +2995,9 @@ static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
if (!io || req->opcode == IORING_OP_SEND)
return 0;
/* iovec is already imported */
if (req->flags & REQ_F_NEED_CLEANUP)
return 0;
io->msg.iov = io->msg.fast_iov;
ret = sendmsg_copy_msghdr(&io->msg.msg, sr->msg, sr->msg_flags,
@ -3143,6 +3148,9 @@ static int io_recvmsg_prep(struct io_kiocb *req,
if (!io || req->opcode == IORING_OP_RECV)
return 0;
/* iovec is already imported */
if (req->flags & REQ_F_NEED_CLEANUP)
return 0;
io->msg.iov = io->msg.fast_iov;
ret = recvmsg_copy_msghdr(&io->msg.msg, sr->msg, sr->msg_flags,