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Sender: Ingo Molnar <mingo.kernel.org@gmail.com>
Date:   Fri, 13 Oct 2023 09:30:46 +0200
From:   Ingo Molnar <mingo@kernel.org>
To:     Dan Carpenter <dan.carpenter@linaro.org>
Cc:     Sandipan Das <sandipan.das@amd.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>, linux-perf-users@vger.kernel.org,
        linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org,
        Uros Bizjak <ubizjak@gmail.com>
Subject: Re: [PATCH] perf/x86/amd/uncore: fix error codes in amd_uncore_init()
Message-ID: <ZSjyJuqk3z0RyKP2@gmail.com>
References: <cec62eba-c4b8-4cb7-9671-58894dd4b974@moroto.mountain>
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* Dan Carpenter <dan.carpenter@linaro.org> wrote:

> Some of the error paths in this function return don't initialize the
> error code.  Return -ENODEV.
> 
> Fixes: d6389d3ccc13 ("perf/x86/amd/uncore: Refactor uncore management")
> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> ---
>  arch/x86/events/amd/uncore.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/events/amd/uncore.c b/arch/x86/events/amd/uncore.c
> index 9b444ce24108..a389828f378c 100644
> --- a/arch/x86/events/amd/uncore.c
> +++ b/arch/x86/events/amd/uncore.c
> @@ -1009,7 +1009,8 @@ static struct amd_uncore uncores[UNCORE_TYPE_MAX] = {
>  static int __init amd_uncore_init(void)
>  {
>  	struct amd_uncore *uncore;
> -	int ret, i;
> +	int ret = -ENODEV;
> +	int i;
>  
>  	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
>  	    boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)

Ugh, why on Earth didn't GCC warn about this? The bad pattern is pretty 
simple & obvious once pointed out ... compilers should have no trouble 
realizing that 'ret' is returned uninitialized in some of these control 
paths. Yet not a peep from the compiler ...

Thanks for the fix!

	Ingo