From: Greg KH <gregkh@linuxfoundation.org>
To: Christoph Hellwig <hch@lst.de>
Cc: viro@zeniv.linux.org.uk, Avi Kivity <avi@scylladb.com>,
linux-aio@kvack.org, linux-fsdevel@vger.kernel.org,
linux-api@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/9] aio: sanitize ki_list handling
Date: Wed, 21 Mar 2018 10:16:48 +0100 [thread overview]
Message-ID: <20180321091648.GL14085@kroah.com> (raw)
In-Reply-To: <20180321073232.13366-5-hch@lst.de>
On Wed, Mar 21, 2018 at 08:32:27AM +0100, Christoph Hellwig wrote:
> 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: Christoph Hellwig <hch@lst.de>
> Acked-by: Jeff Moyer <jmoyer@redhat.com>
> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
> fs/aio.c | 13 ++++++-------
> 1 file changed, 6 insertions(+), 7 deletions(-)
>
> diff --git a/fs/aio.c b/fs/aio.c
> index 6295fc00f104..c32c315f05b5 100644
> --- a/fs/aio.c
> +++ b/fs/aio.c
> @@ -555,13 +555,12 @@ 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;
Will be fun to see if the syzkaller code ends up tripping on this one,
their use of panic-on-warn always is "interesting"...
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>
> + 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);
> @@ -1034,7 +1033,7 @@ 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:
> @@ -1080,7 +1079,7 @@ static void aio_complete(struct aio_kiocb *iocb, long res, long res2)
> unsigned tail, pos, head;
> unsigned long flags;
>
> - if (iocb->ki_list.next) {
> + if (!list_empty_careful(iocb->ki_list.next)) {
> unsigned long flags;
>
> spin_lock_irqsave(&ctx->ctx_lock, flags);
> --
> 2.14.2
>
> --
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next prev parent reply other threads:[~2018-03-21 9:16 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-21 7:32 io_pgetevents & aio fsync Christoph Hellwig
2018-03-21 7:32 ` [PATCH 1/9] aio: don't print the page size at boot time Christoph Hellwig
2018-03-21 9:12 ` Greg KH
2018-03-21 7:32 ` [PATCH 2/9] aio: remove an outdated comment in aio_complete Christoph Hellwig
2018-03-21 9:14 ` Greg KH
2018-03-21 9:17 ` Christoph Hellwig
2018-03-21 7:32 ` [PATCH 3/9] aio: refactor read/write iocb setup Christoph Hellwig
2018-03-21 9:15 ` Greg KH
2018-03-21 7:32 ` [PATCH 4/9] aio: sanitize ki_list handling Christoph Hellwig
2018-03-21 9:16 ` Greg KH [this message]
2018-03-22 15:24 ` Al Viro
2018-03-22 17:04 ` Christoph Hellwig
2018-03-21 7:32 ` [PATCH 5/9] aio: simplify cancellation Christoph Hellwig
2018-03-21 9:17 ` Greg KH
2018-03-21 16:23 ` Darrick J. Wong
2018-03-21 7:32 ` [PATCH 6/9] aio: delete iocbs from the active_reqs list in kiocb_cancel Christoph Hellwig
2018-03-21 9:17 ` Greg KH
2018-03-21 16:23 ` Darrick J. Wong
2018-03-21 7:32 ` [PATCH 7/9] aio: add delayed cancel support Christoph Hellwig
2018-03-21 9:18 ` Greg KH
2018-03-21 16:23 ` Darrick J. Wong
2018-03-22 16:33 ` Al Viro
2018-03-21 7:32 ` [PATCH 8/9] aio: implement io_pgetevents Christoph Hellwig
2018-03-21 9:24 ` Greg KH
2018-03-21 9:29 ` Christoph Hellwig
2018-03-21 14:39 ` Greg KH
2018-03-21 16:26 ` Darrick J. Wong
2018-03-21 7:32 ` [PATCH 9/9] aio: implement IOCB_CMD_FSYNC and IOCB_CMD_FDSYNC Christoph Hellwig
2018-03-21 9:27 ` Greg KH
2018-03-21 9:30 ` Christoph Hellwig
2018-03-21 16:26 ` Darrick J. Wong
2018-03-22 16:36 ` io_pgetevents & aio fsync Al Viro
2018-03-22 16:36 ` Al Viro
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