Re: [PATCH v2 1/3] PCI/AER: Fix incorrect return from aer_hest_parse()

Chen Gong
2013-06-04T07:49:19Z

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On Thu, May 30, 2013 at 08:39:27AM -0600, Betty Dall wrote:
> Date: Thu, 30 May 2013 08:39:27 -0600
> From: Betty Dall <betty.dall@hp.com>
> To: rjw@sisk.pl, bhelgaas@google.com
> Cc: ying.huang@intel.com, linux-acpi@vger.kernel.org,
> linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, Betty Dall
> <betty.dall@hp.com>
> Subject: [PATCH v2 1/3] PCI/AER: Fix incorrect return from aer_hest_parse()
> X-Mailer: git-send-email 1.7.7.6
>
> The function aer_hest_parse() is called to determine if the given
> PCI device is firmware first or not. The code loops through each
> section of the HEST table to look for a match. The bug is that
> the function always returns whether the last HEST section is firmware
> first. The fix stops the iteration once the info.firmware_first
> variable is set. This is similar to how the function aer_hest_parse_aff()
> stops the iteration.
>
> Signed-off-by: Betty Dall <betty.dall@hp.com>

The patch is good. But I have further concern based on your patch.
1) aer_hest_parse never checks the 2nd input parameter (void *data),
which means once it is NULL, it will crash the kernel.

2) both aer_hest_parse and aer_hest_parse_aff utilize some flag
as shortcut, if so, why not adding similar logic in apei_hest_parse
to stop meaningless loops once FFM is confirmed as enabled.

> ---
>
> drivers/pci/pcie/aer/aerdrv_acpi.c | 3 +++
> 1 files changed, 3 insertions(+), 0 deletions(-)
>
>
> diff --git a/drivers/pci/pcie/aer/aerdrv_acpi.c b/drivers/pci/pcie/aer/aerdrv_acpi.c
> index 5194a7d..39b8671 100644
> --- a/drivers/pci/pcie/aer/aerdrv_acpi.c
> +++ b/drivers/pci/pcie/aer/aerdrv_acpi.c
> @@ -42,6 +42,9 @@ static int aer_hest_parse(struct acpi_hest_header *hest_hdr, void *data)
> u8 bridge = 0;
> int ff = 0;
>
> + if (info->firmware_first)
> + return 0;
> +
> switch (hest_hdr->type) {
> case ACPI_HEST_TYPE_AER_ROOT_PORT:
> pcie_type = PCI_EXP_TYPE_ROOT_PORT;
> --
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