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serial: 8250_mid: Fix NULL function pointer dereference on DNV/ICX-D/SNR platforms

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Commit b1b4efea05 ("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.

Fixes: b1b4efea05 ("serial: 8250_mid: Disable DMA for selected platforms")
Cc: stable <stable@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Jiangshan Yi <yijiangshan@kylinos.cn>
Link: https://patch.msgid.link/20260715073546.1875083-1-yijiangshan@kylinos.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiangshan Yi 2026-07-15 15:35:46 +08:00 committed by Greg Kroah-Hartman
parent a13c140cc2
commit 7fb13fd7e9
1 changed files with 9 additions and 5 deletions
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14
drivers/tty/serial/8250/8250_mid.c
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@ -318,9 +318,11 @@ static int mid8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
if (!uart.port.membase)
return -ENOMEM;
ret = mid->board->setup(mid, &uart.port);
if (ret)
return ret;
if (mid->board->setup) {
ret = mid->board->setup(mid, &uart.port);
if (ret)
return ret;
}
ret = mid8250_dma_setup(mid, &uart);
if (ret)
@ -336,7 +338,8 @@ static int mid8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
return 0;
err:
mid->board->exit(mid);
if (mid->board->exit)
mid->board->exit(mid);
return ret;
}
@ -346,7 +349,8 @@ static void mid8250_remove(struct pci_dev *pdev)
serial8250_unregister_port(mid->line);
mid->board->exit(mid);
if (mid->board->exit)
mid->board->exit(mid);
}
static const struct mid8250_board pnw_board = {