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Message-Id: <3df75cdc89ce91167f0f5fef068dcc27e387c73f.1581157341.git.asml.silence@gmail.com>
Date: Sat, 8 Feb 2020 13:28:02 +0300
From: Pavel Begunkov <asml.silence@...il.com>
To: Jens Axboe <axboe@...nel.dk>, io-uring@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] io_uring: fix double prep iovec leak
Requests may be prepared multiple times with ->io allocated (i.e. async
prepared). Preparation functions doesn'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 to check, whether they already allocated resources,
what is true IFF REQ_F_NEED_CLEANUP is set.
Signed-off-by: Pavel Begunkov <asml.silence@...il.com>
---
fs/io_uring.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 1698b4950366..f5aa2fdccf7a 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2187,7 +2187,8 @@ 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;
@@ -2275,7 +2276,8 @@ 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;
@@ -2981,6 +2983,9 @@ 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,
@@ -3131,6 +3136,9 @@ 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,
--
2.24.0
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