Re: [PATCH 6/7] PCI/AER: Renumber severity constants

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Critical] ras/aer: ABI breakage in aer_event tracepoint severity values
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commit 1b45a2c88d40942123bcb76f3b3bbf8eb9ec2cac
Author: Lukas Wunner <lukas@wunner.de>

PCI/AER: Renumber severity constants

This commit modifies the AER severity constants to align with the Device Status
Register bit numbers defined in the PCIe specification. It updates the severity
strings and the ras_event documentation to reflect the new constant values.

> diff --git a/include/linux/aer.h b/include/linux/aer.h
> index df0f5c382286f..795c551320088 100644
> --- a/include/linux/aer.h
> +++ b/include/linux/aer.h
> @@ -11,10 +11,10 @@
>  #include <linux/errno.h>
>  #include <linux/types.h>
>  
> -#define AER_NONFATAL			0
> -#define AER_FATAL			1
> -#define AER_CORRECTABLE			2
> -#define DPC_FATAL			3
> +/* Must match bit number in Device Status Register (PCIe r7.1, sec 7.5.3.5) */
> +#define AER_CORRECTABLE			0
> +#define AER_NONFATAL			1
> +#define AER_FATAL			2

[ ... ]

> diff --git a/include/ras/ras_event.h b/include/ras/ras_event.h
> index fdb785fa4613a..1e03ade99386b 100644
> --- a/include/ras/ras_event.h
> +++ b/include/ras/ras_event.h
> @@ -302,7 +302,7 @@ TRACE_EVENT(non_standard_event,
>   *			([domain:]bus:device.function).
>   * u32 status -		Either the correctable or uncorrectable register
>   *			indicating what error or errors have been seen
> - * u8 severity -	error severity 0:NONFATAL 1:FATAL 2:CORRECTED
> + * u8 severity -	error severity 0:CORRECTED 1:NONFATAL 2:FATAL
>   */

[Severity: Critical]
Does this change unintentionally break the userspace ABI for the aer_event
tracepoint?

The tracepoint exports the severity field as a raw u8 integer in the binary
trace ring buffer. By renumbering the underlying AER constants in
include/linux/aer.h, the tracepoint now emits different integers for hardware
error events without an ABI translation layer.

Userspace tools like rasdaemon that rely on the historical raw integer values
will now misclassify hardware error severities. For example, a correctable
error (now 0) would be incorrectly interpreted as non-fatal by older tools
expecting the previous ABI layout.

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Sashiko AI review · https://sashiko.dev/#/patchset/cover.1790531238.git.lukas@wunner.de?part=6