From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Jiangshan Yi <yijiangshan@kylinos.cn>
Cc: andy@kernel.org, gregkh@linuxfoundation.org,
jirislaby@kernel.org, linux-serial@vger.kernel.org,
linux-kernel@vger.kernel.org, 13667453960@163.com,
stable@kernel.org
Subject: Re: [PATCH] serial: 8250_mid: Fix NULL function pointer dereference on DNV/ICX-D/SNR platforms
Date: Wed, 15 Jul 2026 09:10:23 +0300 [thread overview]
Message-ID: <alckT06ko8sfvfMV@ashevche-desk.local> (raw)
In-Reply-To: <20260715030336.1512861-1-yijiangshan@kylinos.cn>
On Wed, Jul 15, 2026 at 11:03:36AM +0800, Jiangshan Yi wrote:
> Commit b1b4efea05a5 ("serial: 8250_mid: Disable DMA for selected
> platforms") replaced the dnv_board setup and exit callbacks with
> PTR_IF(false, ...), which evaluates to NULL. However, the three call
> sites in mid8250_probe() and mid8250_remove() unconditionally dereference
> these function pointers without NULL checks, causing a NULL pointer
> dereference (kernel oops) on any Denverton (DNV), Ice Lake Xeon D
> (ICX-D/CDF), or Snowridge (SNR) platform.
>
> Fix this by adding the missing NULL checks before calling the setup
> and exit callbacks.
Oh, thanks!
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
but I have a nit-pick below.
> Fixes: b1b4efea05a5 ("serial: 8250_mid: Disable DMA for selected platforms")
> Cc: stable@kernel.org
> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
These two Cc may be moved either to --to option of `git format-patch` or after
the cutter '---' line to avoid unneeded noise in the commit message.
...
> - ret = mid->board->setup(mid, &uart.port);
> + ret = mid->board->setup ? mid->board->setup(mid, &uart.port) : 0;
> if (ret)
> return ret;
Likewise the rest, this can be also wrapped to the if-condition:
if (mid->board->setup) {
ret = mid->board->setup(mid, &uart.port);
if (ret)
return ret;
}
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2026-07-15 6:10 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-15 3:03 [PATCH] serial: 8250_mid: Fix NULL function pointer dereference on DNV/ICX-D/SNR platforms Jiangshan Yi
2026-07-15 6:10 ` Andy Shevchenko [this message]
2026-07-15 7:13 ` Jiangshan Yi
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