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From:   Kalle Valo <kvalo@kernel.org>
To:     Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= <toke@toke.dk>
Cc:     Kalle Valo <quic_kvalo@quicinc.com>,
        Colin Ian King <colin.i.king@gmail.com>,
        linux-wireless@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] wifi: ath9k: Don't mark channelmap stack variable read-only in ath9k_mci_update_wlan_channels()
References: <20230413214118.153781-1-toke@toke.dk>
Date:   Fri, 14 Apr 2023 13:00:34 +0300
In-Reply-To: <20230413214118.153781-1-toke@toke.dk> ("Toke
        \=\?utf-8\?Q\?H\=C3\=B8iland-J\=C3\=B8rgensen\=22's\?\= message of "Thu, 13 Apr 2023
 23:41:18 +0200")
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Toke H=C3=B8iland-J=C3=B8rgensen <toke@toke.dk> writes:

> This partially reverts commit e161d4b60ae3a5356e07202e0bfedb5fad82c6aa.
>
> Turns out the channelmap variable is not actually read-only, it's modified
> through the MCI_GPM_CLR_CHANNEL_BIT() macro further down in the function,
> so making it read-only causes page faults when that code is hit.
>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=3D217183
> Fixes: e161d4b60ae3 ("wifi: ath9k: Make arrays prof_prio and channelmap s=
tatic const")
> Cc: stable@vger.kernel.org
> Signed-off-by: Toke H=C3=B8iland-J=C3=B8rgensen <toke@toke.dk>

I guess the casting in MCI_GPM_CLR_CHANNEL_BIT() hide this and made it
impossible for the compiler to detect it? A perfect example why I hate
casting :)

--=20
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