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Date:   Mon, 10 Jun 2019 16:21:45 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Ignat Korchagin <ignat@cloudflare.com>
Cc:     Ivan Babrou <ivan@cloudflare.com>,
        Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>,
        Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Ingo Molnar <mingo@redhat.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@redhat.com>,
        Namhyung Kim <namhyung@kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
        kernel-team <kernel-team@cloudflare.com>
Subject: Re: Linux 4.19 and GCC 9
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On Mon, Jun 10, 2019 at 10:32:25AM +0100, Ignat Korchagin wrote:
> Hi Greg,
> 
> For us it seems applying the following 4 mainline patches makes 4.19.x
> branch perf compile with GCC-9:
> 
> 4d0f16d059ddb91424480d88473f7392f24aebdc: perf ui helpline: Use
> strlcpy() as a shorter form of strncpy() + explicit set nul
> b6313899f4ed2e76b8375cf8069556f5b94fbff0: perf help: Remove needless
> use of strncpy()
> 5192bde7d98c99f2cd80225649e3c2e7493722f7: perf header: Fix unchecked
> usage of strncpy()
> 97acec7df172cd1e450f81f5e293c0aa145a2797: perf data: Fix 'strncat may
> truncate' build failure with recent gcc
> 
> I also checked that 4.19.49 compiles fine with GCC 9, although with a
> lot of warnings, mostly from objtool, like "warning: objtool:
> sock_register()+0xd: sibling call from callable instruction with
> modified stack frame". But it's a start.
> 
> Can we apply the above-mentioned patches, please?

I'll look into these after the next round of kernels are released.  I
guess I'll go find a distro that has gcc9 on it to actually test
things...

thanks,

greg k-h