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io_uring/msg_ring: fix missing lock on overflow for IOPOLL

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If the target ring is configured with IOPOLL, then we always need to hold
the target ring uring_lock before posting CQEs. We could just grab it
unconditionally, but since we don't expect many target rings to be of this
type, make grabbing the uring_lock conditional on the ring type.

Link: https://lore.kernel.org/io-uring/Y8krlYa52%2F0YGqkg@ip-172-31-85-199.ec2.internal/
Reported-by: Xingyuan Mo <hdthky0@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2023-01-19 09:04:40 -07:00
parent 423d5081d0
commit e12d7a46f6
1 changed files with 30 additions and 9 deletions
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39
io_uring/msg_ring.c
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@ -65,20 +65,33 @@ static void io_msg_tw_complete(struct callback_head *head)
struct io_ring_ctx *target_ctx = req->file->private_data;
int ret = 0;
if (current->flags & PF_EXITING)
if (current->flags & PF_EXITING) {
ret = -EOWNERDEAD;
else if (!io_post_aux_cqe(target_ctx, msg->user_data, msg->len, 0))
ret = -EOVERFLOW;
} else {
/*
* If the target ring is using IOPOLL mode, then we need to be
* holding the uring_lock for posting completions. Other ring
* types rely on the regular completion locking, which is
* handled while posting.
*/
if (target_ctx->flags & IORING_SETUP_IOPOLL)
mutex_lock(&target_ctx->uring_lock);
if (!io_post_aux_cqe(target_ctx, msg->user_data, msg->len, 0))
ret = -EOVERFLOW;
if (target_ctx->flags & IORING_SETUP_IOPOLL)
mutex_unlock(&target_ctx->uring_lock);
}
if (ret < 0)
req_set_fail(req);
io_req_queue_tw_complete(req, ret);
}
static int io_msg_ring_data(struct io_kiocb *req)
static int io_msg_ring_data(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_ring_ctx *target_ctx = req->file->private_data;
struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
int ret;
if (msg->src_fd || msg->dst_fd || msg->flags)
return -EINVAL;
@ -93,10 +106,18 @@ static int io_msg_ring_data(struct io_kiocb *req)
return IOU_ISSUE_SKIP_COMPLETE;
}
if (io_post_aux_cqe(target_ctx, msg->user_data, msg->len, 0))
return 0;
return -EOVERFLOW;
ret = -EOVERFLOW;
if (target_ctx->flags & IORING_SETUP_IOPOLL) {
if (unlikely(io_double_lock_ctx(target_ctx, issue_flags)))
return -EAGAIN;
if (io_post_aux_cqe(target_ctx, msg->user_data, msg->len, 0))
ret = 0;
io_double_unlock_ctx(target_ctx);
} else {
if (io_post_aux_cqe(target_ctx, msg->user_data, msg->len, 0))
ret = 0;
}
return ret;
}
static struct file *io_msg_grab_file(struct io_kiocb *req, unsigned int issue_flags)
@ -223,7 +244,7 @@ int io_msg_ring(struct io_kiocb *req, unsigned int issue_flags)
switch (msg->cmd) {
case IORING_MSG_DATA:
ret = io_msg_ring_data(req);
ret = io_msg_ring_data(req, issue_flags);
break;
case IORING_MSG_SEND_FD:
ret = io_msg_send_fd(req, issue_flags);