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From: Baichuan Qi <zghbqbc@gmail.com>
To: quic_vthiagar@quicinc.com
Cc: ath11k@lists.infradead.org, jjohnson@kernel.org,
	kvalo@kernel.org, linux-kernel@vger.kernel.org,
	linux-wireless@vger.kernel.org, markus.elfring@web.de,
	zghbqbc@gmail.com
Subject: Re: Re: [PATCH v5] NAK
Date: Thu, 28 Nov 2024 14:09:31 +0800	[thread overview]
Message-ID: <20241128060931.94100-1-zghbqbc@gmail.com> (raw)
In-Reply-To: <f0077f4f-922d-56b1-a5b7-bb01e4462e87@quicinc.com>

Thanks for your reply

The reason I submit this patch is that the current 
`ath11k_ce_rx_post_pipe()` NULL pointer check does not ensure 
that `dest_ring` is NON-NULL. And it is not clear to show the 
filtering of tx ce pipes

> This does not really fix any real issue. Please check ath11k_ce_alloc_pipe()
> where initialization would fail if anyone of pipe->dest_ring and
> pipe->status_ring allocation fails for ce pipe used for Rx.

When the driver is running normally, the results of the 
following three are equal:
---
(pipe->dest_ring || pipe->status_ring) // current code
(pipe->dest_ring && pipe->status_ring)
(pipe->dest_ring)
---
However, when some errors occur and `dest_ring` is abnormal,
the OR operation cannot guarantee that the pointer is NON-NULL.

> This will always fail as the caller loops through all the supported ce pipes
> and ce pipes used for Tx will not have either dest_ring or status_ring.
> Please ensure the patch is tested properly.

I tested [PATCH v5] and indeed the wrong return value will lead 
to wrong results when the pointer is null.

Please refer to [PATCH v4].
Link: https://lore.kernel.org/ath11k/20241127114310.26085-1-zghbqbc@gmail.com/
Although it does not return an error code, it can ensure that 
when an unknown error occurs and causes the status of 
`dest_ring` and `status_ring` to be different, the subsequent 
code will not access the null pointer, which will only 
cause the driver to fall into loops.

Thanks for you read.

Thanks
Baichuan Qi

  reply	other threads:[~2024-11-28  6:09 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-11-25  5:08 [PATCH] wifi: ath11k: Fix NULL pointer check in ath11k_ce_rx_post_pipe() Baichuan Qi
2024-11-25 10:34 ` Markus Elfring
2024-11-26  2:33   ` Baichuan Qi
2024-11-26 13:44     ` Markus Elfring
2024-11-27  3:28       ` zgBCQ
2024-11-27 12:40         ` Markus Elfring
2024-11-27 14:35           ` Re: wifi: ath11k: Fix NULL pointer check in ath11k_ce_rx_post_pipe() ERROR code Baichuan Qi
2024-11-27 14:38           ` [PATCH v5] wifi: ath11k: Fix NULL pointer check in ath11k_ce_rx_post_pipe() Baichuan Qi
2024-11-27 15:23             ` Vasanthakumar Thiagarajan
2024-11-28  6:09               ` Baichuan Qi [this message]
2024-11-27  3:32       ` [PATCH v2 1/1] " Baichuan Qi
2024-11-27  9:05         ` [PATCH v4?] " Markus Elfring
2024-11-27  9:43           ` [PATCH v3] " Baichuan Qi
2024-11-27 10:30             ` Kang Yang
2024-11-27 12:00               ` Baichuan Qi
2024-11-27 10:36             ` [PATCH v4?] " Markus Elfring
2024-11-27 11:43               ` [PATCH v4] " Baichuan Qi

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