From: Tariq Toukan <tariqt@nvidia.com>
To: Leon Romanovsky <leon@kernel.org>, Yuho Choi <oss.patchbox@gmail.com>
Cc: Saeed Mahameed <saeedm@nvidia.com>,
Tariq Toukan <tariqt@nvidia.com>, Mark Bloch <mbloch@nvidia.com>,
Andrew Lunn <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@kernel.org>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Ariel Levkovich <lariel@nvidia.com>,
Jianbo Liu <jianbol@nvidia.com>, Alex Vesker <valex@nvidia.com>,
Yevgeny Kliteynik <kliteyn@nvidia.com>,
Itamar Gozlan <igozlan@nvidia.com>,
netdev@vger.kernel.org, linux-rdma@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next v1 0/4] net/mlx5: Don't free CQs whose destroy failed
Date: Tue, 20 Oct 2026 09:35:03 +0300 [thread overview]
Message-ID: <84200f4f-6d39-4941-95fb-675bc8d8ae83@nvidia.com> (raw)
In-Reply-To: <20261018125520.GE64621@unreal>
On 18/10/2026 15:55, Leon Romanovsky wrote:
> On Fri, Oct 16, 2026 at 12:57:45AM -0400, Yuho Choi wrote:
>> mlx5_core_destroy_cq() can fail
>
> No, it should not fail. If it does, the firmware is completely broken
> or some other catastrophic bug.
>
>> nd when it does the CQ may still exist in firmware with access to its buffer and doorbell record. It
>> also returns early in that case, without waiting for EQ handlers that
>> may already hold a reference to the CQ. The four helpers in this series
>> ignore that error and free the CQ buffer anyway, while their teardown
>> paths also free the object that embeds the struct mlx5_core_cq.
>>
>> Keep the buffer and the object that embeds the CQ when DESTROY_CQ
>> fails, as the regular mlx5_ib CQ destroy path does. The HWS send ring
>> CQs are polled and never armed, so the HWS patch keeps only their
>> buffer rather than passing the error up through the queue open and
>> close paths.
>>
>> The issues were found with a static analysis tool from ongoing, not yet
>> published research, and confirmed by code inspection. None of them was
>> reproduced, so this targets net-next; I can resend for net if you
>> prefer.
>
> Please drop this series. The flow is impossible in current HW implementation.
>
> Thanks
pw-bot: cr
prev parent reply other threads:[~2026-10-20 6:35 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-16 4:57 Yuho Choi
2026-10-16 4:57 ` [PATCH net-next v1 1/4] net/mlx5: Don't free the ASO CQ if destroying it fails Yuho Choi
2026-10-20 5:24 ` netdev-bot+sashiko
2026-10-16 4:57 ` [PATCH net-next v1 2/4] net/mlx5: Don't free the WC test " Yuho Choi
2026-10-20 5:24 ` netdev-bot+sashiko
2026-10-16 4:57 ` [PATCH net-next v1 3/4] net/mlx5: DR, Don't free the send ring " Yuho Choi
2026-10-16 4:57 ` [PATCH net-next v1 4/4] net/mlx5: HWS, Don't free the send ring CQ buffer if destroying the CQ fails Yuho Choi
2026-10-16 6:59 ` [PATCH net-next v1 0/4] net/mlx5: Don't free CQs whose destroy failed Junxian Huang
2026-10-16 13:30 ` Yuho Choi
2026-10-18 12:55 ` Leon Romanovsky
2026-10-18 17:51 ` Yuho Choi
2026-10-20 6:35 ` Tariq Toukan [this message]
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