Re: [PATCH] serial: 8250_mid: Fix NULL function pointer dereference on DNV/ICX-D/SNR platforms
Andy Shevchenko <[email protected]>
| Newsgroups | org.kernel.vger.linux-serial,org.kernel.vger.linux-kernel |
|---|---|
| Organization | Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo |
| Message-ID | <[email protected]> |
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 <[email protected]>
but I have a nit-pick below.
> Fixes: b1b4efea05a5 ("serial: 8250_mid: Disable DMA for selected platforms")
> Cc: [email protected]
> Cc: Andy Shevchenko <[email protected]>
> Cc: Greg Kroah-Hartman <[email protected]>
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