linux-kernel - Re: [PATCH V2] perf/x86/intel/uncore: Fix iounmap() leak on global

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Message-ID: <b09f882b-fa14-4ccb-aee5-7024747af83c@linux.intel.com>
Date: Mon, 19 Jan 2026 08:48:08 +0800
From: "Mi, Dapeng" <dapeng1.mi@...ux.intel.com>
To: Zide Chen <zide.chen@...el.com>, Peter Zijlstra <peterz@...radead.org>,
 Ingo Molnar <mingo@...hat.com>, Arnaldo Carvalho de Melo <acme@...nel.org>,
 Namhyung Kim <namhyung@...nel.org>, Ian Rogers <irogers@...gle.com>,
 Adrian Hunter <adrian.hunter@...el.com>,
 Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
 Andi Kleen <ak@...ux.intel.com>, Eranian Stephane <eranian@...gle.com>,
 Markus Elfring <Markus.Elfring@....de>
Cc: linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
 Xudong Hao <xudong.hao@...el.com>, Falcon Thomas <thomas.falcon@...el.com>,
 kernel test robot <lkp@...el.com>
Subject: Re: [PATCH V2] perf/x86/intel/uncore: Fix iounmap() leak on
 global_init failure


On 1/15/2026 3:38 AM, Zide Chen wrote:
> Kernel test robot reported:
>
> Unverified Error/Warning (likely false positive, kindly check if
> interested):
>     arch/x86/events/intel/uncore_discovery.c:293:2-8:
>     ERROR: missing iounmap; ioremap on line 288 and execution via
>     conditional on line 292
>
> If domain->global_init() fails in __parse_discovery_table(), the
> ioremap'ed MMIO region is not released before returning, resulting
> in an MMIO mapping leak.
>
> Reported-by: kernel test robot <lkp@...el.com>
> Fixes: b575fc0e3357 ("perf/x86/intel/uncore: Add domain global init callback")
> Signed-off-by: Zide Chen <zide.chen@...el.com>
> ---
>  arch/x86/events/intel/uncore_discovery.c | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/events/intel/uncore_discovery.c b/arch/x86/events/intel/uncore_discovery.c
> index 0e414cecb6f2..efd1fc99a908 100644
> --- a/arch/x86/events/intel/uncore_discovery.c
> +++ b/arch/x86/events/intel/uncore_discovery.c
> @@ -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 *domain,

LGTM.

Reviewed-by: Dapeng Mi <dapeng1.mi@...ux.intel.com>