Re: [PATCH] perf/x86/intel/uncore: Fix iounmap() leak on global_init failure

Markus Elfring
2026-01-14T07:51:12Z

>>> If domain->global_init() fails in __parse_discovery_table(), the
>>> mapped MMIO region is not released before returning, resulting in
>>> an iounmap() leak.
>>
>> How do you think about to avoid a bit of duplicate source code here?
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/coding-style.rst?h=v6.19-rc5#n526
>
> Thank you for the suggestion!
>
> Yes, I agree this is better.

Thanks for this positive feedback.

> In V1 I followed the existing style in this API.

This variant might be nicer for backporting.

> I will post a v2 with this change:
>
> @@ -264,6 +264,7 @@ static int __parse_discovery_table(struct
> uncore_discovery_domain *domain,
> struct uncore_unit_discovery unit;
> void __iomem *io_addr;
> unsigned long size;
> + int ret = 0;
> int i;

Would scope adjustments become helpful for any of these local vartiables?

> size = UNCORE_DISCOVERY_GLOBAL_MAP_SIZE;
> @@ -273,21 +274,23 @@ static int __parse_discovery_table(struct
…
> - if (domain->global_init && domain->global_init(global.ctl))
> - return -ENODEV;
> + if (domain->global_init && domain->global_init(global.ctl)) {
> + ret = -ENODEV;
> + goto out;
> + }
…
> *parsed = true;
> +
> +out:

Would an other label be a bit clearer here?

unmap_io:

> iounmap(io_addr);
> - return 0;
> + return ret;
> }
>
> static int parse_discovery_table(struct uncore_discovery_domain
>
>> See also once more:
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.19-rc5#n94

Will another imperative wording become helpful for an improved change description?

> Are you suggesting that I add a Closes tag?

It depends …

> This issue was reported by Intel internal LKP, and there is no public
> URL available.

Thanks for such a bit of background information.
Some contributors would appreciate further hints on involved development tools
(and known source code analysis approaches).

Regards,
Markus