linux-kernel - Re: [PATCH] perf/x86/intel/uncore: Fix iounmap() leak on global

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Message-ID: <548c93bc-bba4-4257-a8da-5cc384a2ec7b@web.de>
Date: Wed, 14 Jan 2026 08:25:32 +0100
From: Markus Elfring <Markus.Elfring@....de>
To: "Chen, Zide" <zide.chen@...el.com>, linux-perf-users@...r.kernel.org,
 Adrian Hunter <adrian.hunter@...el.com>,
 Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
 Andi Kleen <ak@...ux.intel.com>, Arnaldo Carvalho de Melo <acme@...nel.org>,
 Dapeng Mi <dapeng1.mi@...ux.intel.com>, Eranian Stephane
 <eranian@...gle.com>, Ian Rogers <irogers@...gle.com>,
 Ingo Molnar <mingo@...hat.com>, Peter Zijlstra <peterz@...radead.org>,
 Namhyung Kim <namhyung@...nel.org>
Cc: lkp@...el.com, LKML <linux-kernel@...r.kernel.org>,
 Thomas Falcon <thomas.falcon@...el.com>, Xudong Hao <xudong.hao@...el.com>
Subject: Re: [PATCH] perf/x86/intel/uncore: Fix iounmap() leak on global_init
 failure



Am 13.01.26 um 23:04 schrieb Chen, Zide:
> 
> 
> On 1/13/2026 8:21 AM, Markus Elfring wrote:
>>> 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. In V1 I followed the existing style in this
> API.
> 
> 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;
> 
>         size = UNCORE_DISCOVERY_GLOBAL_MAP_SIZE;
> @@ -273,21 +274,23 @@ static int __parse_discovery_table(struct
> uncore_discovery_domain *domain,
> 
>         /* Read Global Discovery State */
>         memcpy_fromio(&global, io_addr, sizeof(struct
> uncore_global_discovery));
> +       iounmap(io_addr);
> +
>         if (uncore_discovery_invalid_unit(global)) {
>                 pr_info("Invalid Global Discovery State: 0x%llx 0x%llx
> 0x%llx\n",
>                         global.table1, global.ctl, global.table3);
> -               iounmap(io_addr);
>                 return -EINVAL;
>         }
> -       iounmap(io_addr);
> 
>         size = (1 + global.max_units) * global.stride * 8;
>         io_addr = ioremap(addr, size);
>         if (!io_addr)
>                 return -ENOMEM;
> 
> -       if (domain->global_init && domain->global_init(global.ctl))
> -               return -ENODEV;
> +       if (domain->global_init && domain->global_init(global.ctl)) {
> +               ret = -ENODEV;
> +               goto out;
> +       }
> 
>         /* Parsing Unit Discovery State */
>         for (i = 0; i < global.max_units; i++) {
> @@ -307,8 +310,10 @@ static int __parse_discovery_table(struct
> uncore_discovery_domain *domain,
>         }
> 
>         *parsed = true;
> +
> +out:
>         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
> 
> Are you suggesting that I add a Closes tag?
> This issue was reported by Intel internal LKP, and there is no public
> URL available.
> 
> 
>> Regards,
>> Markus
>