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From: Al Viro <viro@ZenIV.linux.org.uk>
To: Christoph Hellwig <hch@lst.de>
Cc: Avi Kivity <avi@scylladb.com>,
	linux-aio@kvack.org, linux-fsdevel@vger.kernel.org,
	netdev@vger.kernel.org, linux-api@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 08/32] aio: replace kiocb_set_cancel_fn with a cancel_kiocb file operation
Date: Fri, 6 Apr 2018 03:15:53 +0100	[thread overview]
Message-ID: <20180406021553.GS30522@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20180330150809.28094-9-hch@lst.de>

On Fri, Mar 30, 2018 at 05:07:45PM +0200, Christoph Hellwig wrote:
> The current kiocb_set_cancel_fn implementation assumes the kiocb is
> embedded into an aio_kiocb, which is fundamentally unsafe as it might
> have been submitted by non-aio callers.  Instead add a cancel_kiocb
> file operation that replaced the ki_cancel function pointer set by
> kiocb_set_cancel_fn, and only adds iocbs to the active list when
> the read/write_iter methods return -EIOCBQUEUED and the file has
> a cancel_kiocb method.

> @@ -1440,6 +1423,16 @@ static inline ssize_t aio_rw_ret(struct kiocb *req, ssize_t ret)
>  {
>  	switch (ret) {
>  	case -EIOCBQUEUED:
> +		if (req->ki_filp->f_op->cancel_kiocb) {

... and by that point req might've been already freed by IO completion on
another CPU.
> +			struct aio_kiocb *iocb =
> +				container_of(req, struct aio_kiocb, rw);
> +			struct kioctx *ctx = iocb->ki_ctx;
> +			unsigned long flags;
> +
> +			spin_lock_irqsave(&ctx->ctx_lock, flags);
> +			list_add_tail(&iocb->ki_list, &ctx->active_reqs);

  reply	other threads:[~2018-04-06  2:15 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-30 15:07 aio poll and a new in-kernel poll API V9 Christoph Hellwig
2018-03-30 15:07 ` [PATCH 01/32] fs: unexport poll_schedule_timeout Christoph Hellwig
2018-03-30 15:07 ` [PATCH 02/32] fs: cleanup do_pollfd Christoph Hellwig
2018-03-30 15:07 ` [PATCH 03/32] fs: update documentation to mention __poll_t and match the code Christoph Hellwig
2018-03-30 15:07 ` [PATCH 04/32] fs: add new vfs_poll and file_can_poll helpers Christoph Hellwig
2018-03-30 15:07 ` [PATCH 05/32] fs: introduce new ->get_poll_head and ->poll_mask methods Christoph Hellwig
2018-04-06  4:58   ` Al Viro
2018-03-30 15:07 ` [PATCH 06/32] aio: simplify KIOCB_KEY handling Christoph Hellwig
2018-03-30 15:07 ` [PATCH 07/32] aio: simplify cancellation Christoph Hellwig
2018-03-30 15:07 ` [PATCH 08/32] aio: replace kiocb_set_cancel_fn with a cancel_kiocb file operation Christoph Hellwig
2018-04-06  2:15   ` Al Viro [this message]
2018-03-30 15:07 ` [PATCH 09/32] aio: add delayed cancel support Christoph Hellwig
2018-03-30 15:07 ` [PATCH 10/32] aio: implement IOCB_CMD_POLL Christoph Hellwig
2018-03-30 15:07 ` [PATCH 11/32] net: refactor socket_poll Christoph Hellwig
2018-03-30 15:07 ` [PATCH 12/32] net: add support for ->poll_mask in proto_ops Christoph Hellwig
2018-03-30 15:07 ` [PATCH 13/32] net: remove sock_no_poll Christoph Hellwig
2018-03-30 15:07 ` [PATCH 14/32] net/tcp: convert to ->poll_mask Christoph Hellwig
2018-03-30 15:07 ` [PATCH 15/32] net/unix: " Christoph Hellwig
2018-03-30 15:07 ` [PATCH 16/32] net: convert datagram_poll users tp ->poll_mask Christoph Hellwig
2018-03-30 15:07 ` [PATCH 17/32] net/dccp: convert to ->poll_mask Christoph Hellwig
2018-03-30 15:07 ` [PATCH 18/32] net/atm: " Christoph Hellwig
2018-03-30 15:07 ` [PATCH 19/32] net/vmw_vsock: " Christoph Hellwig
2018-03-30 15:07 ` [PATCH 20/32] net/tipc: " Christoph Hellwig
2018-03-30 15:07 ` [PATCH 21/32] net/sctp: " Christoph Hellwig
2018-03-30 15:07 ` [PATCH 22/32] net/bluetooth: " Christoph Hellwig
2018-03-30 15:08 ` [PATCH 23/32] net/caif: " Christoph Hellwig
2018-03-30 15:08 ` [PATCH 24/32] net/nfc: " Christoph Hellwig
2018-03-30 15:08 ` [PATCH 25/32] net/phonet: " Christoph Hellwig
2018-03-30 15:08 ` [PATCH 26/32] net/iucv: " Christoph Hellwig
2018-03-30 15:08 ` [PATCH 27/32] net/rxrpc: " Christoph Hellwig
2018-03-30 15:08 ` [PATCH 28/32] crypto: af_alg: " Christoph Hellwig
2018-03-30 15:08 ` [PATCH 29/32] pipe: " Christoph Hellwig
2018-03-30 15:08 ` [PATCH 30/32] eventfd: switch " Christoph Hellwig
2018-03-30 15:08 ` [PATCH 31/32] timerfd: convert " Christoph Hellwig
2018-03-30 15:08 ` [PATCH 32/32] random: " Christoph Hellwig
2018-05-11 11:07 aio poll and a new in-kernel poll API V10 Christoph Hellwig
2018-05-11 11:07 ` [PATCH 08/32] aio: replace kiocb_set_cancel_fn with a cancel_kiocb file operation Christoph Hellwig
2018-05-15 19:48 aio poll and a new in-kernel poll API V11 Christoph Hellwig
2018-05-15 19:48 ` [PATCH 08/32] aio: replace kiocb_set_cancel_fn with a cancel_kiocb file operation Christoph Hellwig
2018-05-20  5:27   ` Al Viro

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