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

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Message-ID: <fc565620-a3ef-4a28-bfb8-87bb5ce135f5@intel.com>
Date: Tue, 13 Jan 2026 14:04:49 -0800
From: "Chen, Zide" <zide.chen@...el.com>
To: Markus Elfring <Markus.Elfring@....de>, 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



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