From: Jakub Kicinski <kuba@kernel.org>
To: Vadim Fedorenko <vadfed@meta.com>
Cc: Vadim Fedorenko <vadim.fedorenko@linux.dev>,
Rahul Rameshbabu <rrameshbabu@nvidia.com>,
"Tariq Toukan" <ttoukan.linux@gmail.com>,
Gal Pressman <gal@nvidia.com>,
"Saeed Mahameed" <saeed@kernel.org>, <netdev@vger.kernel.org>
Subject: Re: [PATCH net v4 2/2] mlx5: fix possible ptp queue fifo use-after-free
Date: Wed, 1 Feb 2023 19:08:01 -0800 [thread overview]
Message-ID: <20230201190801.5082bb49@kernel.org> (raw)
In-Reply-To: <20230201122605.1350664-3-vadfed@meta.com>
On Wed, 1 Feb 2023 04:26:05 -0800 Vadim Fedorenko wrote:
> + if (skb_cc > skb_id || PTP_WQE_CTR2IDX(ptpsq->skb_fifo_pc) < skb_id) {
FWIW I still can't understand why this is correct. If we lose ts for
the last elem before wrap we'll see something like (assume wrap at 256
for easier math):
cc: 255 pc: 2 skb_id: 0 => cc > skb_id, OOO, drop
cc: 255 pc: 2 skb_id: 1 => cc > skb_id, OOO, drop
cc: 255 pc: 3 // produce
cc: 255 pc: 3 skb_id: 2 => cc > skb_id, OOO, drop
cc: 255 pc: 4 // produce
cc: 255 pc: 4 skb_id: 3 => cc > skb_id, OOO, drop
No?
next prev parent reply other threads:[~2023-02-02 3:08 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-01 12:26 [PATCH net v4 0/2] mlx5: ptp fifo bugfixes Vadim Fedorenko
2023-02-01 12:26 ` [PATCH net v4 1/2] mlx5: fix skb leak while fifo resync and push Vadim Fedorenko
2023-02-01 12:26 ` [PATCH net v4 2/2] mlx5: fix possible ptp queue fifo use-after-free Vadim Fedorenko
2023-02-01 18:19 ` Saeed Mahameed
2023-02-01 21:36 ` Vadim Fedorenko
2023-02-01 23:40 ` Saeed Mahameed
2023-02-02 1:34 ` Vadim Fedorenko
2023-02-02 3:01 ` Jakub Kicinski
2023-02-02 3:08 ` Jakub Kicinski [this message]
2023-02-02 11:48 ` Vadim Fedorenko
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