Commit 75321b50 authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

aio: sanitize ki_list handling 



Instead of handcoded non-null checks always initialize ki_list to an
empty list and use list_empty / list_empty_careful on it.  While we're
at it also error out on a double call to kiocb_set_cancel_fn instead
of ignoring it.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarJeff Moyer <jmoyer@redhat.com>
Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
parent c213dc82

fs/aio.c

+6 −7
Original line number Diff line number Diff line
@@ -553,13 +553,12 @@ void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel) 
	struct kioctx *ctx = req->ki_ctx;

	unsigned long flags;



	spin_lock_irqsave(&ctx->ctx_lock, flags);



	if (!req->ki_list.next)

		list_add(&req->ki_list, &ctx->active_reqs);

	if (WARN_ON_ONCE(!list_empty(&req->ki_list)))

		return;



	spin_lock_irqsave(&ctx->ctx_lock, flags);

	list_add_tail(&req->ki_list, &ctx->active_reqs);

	req->ki_cancel = cancel;



	spin_unlock_irqrestore(&ctx->ctx_lock, flags);

}

EXPORT_SYMBOL(kiocb_set_cancel_fn);
@@ -1039,7 +1038,7 @@ static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx) 
		goto out_put;



	percpu_ref_get(&ctx->reqs);



	INIT_LIST_HEAD(&req->ki_list);

	req->ki_ctx = ctx;

	return req;

out_put:
@@ -1107,7 +1106,7 @@ static void aio_complete(struct kiocb *kiocb, long res, long res2) 
		file_end_write(file);

	}



	if (iocb->ki_list.next) {

	if (!list_empty_careful(&iocb->ki_list)) {

		unsigned long flags;



		spin_lock_irqsave(&ctx->ctx_lock, flags);

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