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Date: Thu, 26 Jan 2017 10:00:44 +1100
From: Anton Blanchard <anton@samba.org>
To: Michael Ellerman <mpe@ellerman.id.au>, Benjamin Herrenschmidt
 <benh@kernel.crashing.org>, Paul Mackerras <paulus@samba.org>,
 rric@kernel.org
Cc: linuxppc-dev@lists.ozlabs.org, oprofile-list@lists.sf.net
Subject: gcc trunk fails to build kernel on PowerPC64 due to oprofile warnings
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Hi,

gcc trunk has failed to build PowerPC64 kernels for a month or so. The issue
is in oprofile, which is common code but ends up being sucked into
arch/powerpc and therefore subject to the -Werror applied to arch/powerpc:
=20
linux/arch/powerpc/oprofile/../../../drivers/oprofile/oprofile_stats.c: In =
function =E2=80=98oprofile_create_stats_files=E2=80=99:
linux/arch/powerpc/oprofile/../../../drivers/oprofile/oprofile_stats.c:55:2=
5: error: =E2=80=98%d=E2=80=99 directive output may be truncated writing be=
tween 1 and 11 bytes into a region of size 7 [-Werror=3Dformat-truncation=
=3D]
   snprintf(buf, 10, "cpu%d", i);
                         ^~
linux/arch/powerpc/oprofile/../../../drivers/oprofile/oprofile_stats.c:55:2=
1: note: using the range [1, -2147483648] for directive argument
   snprintf(buf, 10, "cpu%d", i);
                     ^~~~~~~
linux/arch/powerpc/oprofile/../../../drivers/oprofile/oprofile_stats.c:55:3=
: note: format output between 5 and 15 bytes into a destination of size 10
   snprintf(buf, 10, "cpu%d", i);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  LD      crypto/async_tx/built-in.o
  CC      lib/random32.o
cc1: all warnings being treated as errors

Anton