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Subject: Re: [PATCH v5] perf tools: Fix arm64 build error with gcc-11
To:     Jianlin Lv <Jianlin.Lv@arm.com>, <will@kernel.org>,
        <mathieu.poirier@linaro.org>, <leo.yan@linaro.org>,
        <peterz@infradead.org>, <mingo@redhat.com>, <acme@kernel.org>,
        <mark.rutland@arm.com>, <alexander.shishkin@linux.intel.com>,
        <jolsa@redhat.com>, <namhyung@kernel.org>, <guoren@kernel.org>,
        <paul.walmsley@sifive.com>, <palmer@dabbelt.com>,
        <aou@eecs.berkeley.edu>, <kjain@linux.ibm.com>,
        <atrajeev@linux.vnet.ibm.com>, <ravi.bangoria@linux.ibm.com>,
        <anju@linux.vnet.ibm.com>
CC:     <iecedge@gmail.com>, <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-csky@vger.kernel.org>, <linux-riscv@lists.infradead.org>
References: <20210218031245.2078492-1-Jianlin.Lv@arm.com>
From:   John Garry <john.garry@huawei.com>
Message-ID: <bd474bfa-2bdb-53ea-5142-3a6570d63b7f@huawei.com>
Date:   Thu, 18 Feb 2021 09:26:17 +0000
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On 18/02/2021 03:12, Jianlin Lv wrote:
> gcc version: 11.0.0 20210208 (experimental) (GCC)
> 
> Following build error on arm64:
> 
> .......
> In function ‘printf’,
>      inlined from ‘regs_dump__printf’ at util/session.c:1141:3,
>      inlined from ‘regs__printf’ at util/session.c:1169:2:
> /usr/include/aarch64-linux-gnu/bits/stdio2.h:107:10: \
>    error: ‘%-5s’ directive argument is null [-Werror=format-overflow=]
> 
> 107 |   return __printf_chk (__USE_FORTIFY_LEVEL - 1, __fmt, \
>                  __va_arg_pack ());
> 
> ......
> In function ‘fprintf’,
>    inlined from ‘perf_sample__fprintf_regs.isra’ at \
>      builtin-script.c:622:14:
> /usr/include/aarch64-linux-gnu/bits/stdio2.h:100:10: \
>      error: ‘%5s’ directive argument is null [-Werror=format-overflow=]
>    100 |   return __fprintf_chk (__stream, __USE_FORTIFY_LEVEL - 1, __fmt,
>    101 |                         __va_arg_pack ());
> 
> cc1: all warnings being treated as errors
> .......
> 
> This patch fixes Wformat-overflow warnings. Add helper function to
> convert NULL to "unknown".
> 
> Signed-off-by: Jianlin Lv<Jianlin.Lv@arm.com>

thanks
Reviewed-by: John Garry <john.garry@huawei.com>