linux-kernel - Re: [PATCH RESEND] powerpc/tools: drop `-o pipefail` in gcc check scripts

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Message-ID: <d2e51443-49dd-445a-88aa-f29d7b777bce@csgroup.eu>
Date: Mon, 10 Nov 2025 12:33:22 +0100
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Jan Stancek <jstancek@...hat.com>,
 Justin Forbes <jforbes@...oraproject.org>
Cc: maddy@...ux.ibm.com, mpe@...erman.id.au, linuxppc-dev@...ts.ozlabs.org,
 npiggin@...il.com, linux-kernel@...r.kernel.org, joe.lawrence@...hat.com
Subject: Re: [PATCH RESEND] powerpc/tools: drop `-o pipefail` in gcc check
 scripts



Le 30/10/2025 à 19:09, Jan Stancek a écrit :
> On Mon, Oct 6, 2025 at 10:19 PM Justin Forbes <jforbes@...oraproject.org> wrote:
>>
>> On Tue, Sep 23, 2025 at 9:31 AM Jan Stancek <jstancek@...hat.com> wrote:
>>>
>>> We've been observing rare non-deterministic kconfig failures during
>>> olddefconfig, where ARCH_USING_PATCHABLE_FUNCTION_ENTRY was getting
>>> disabled and with it number of other config options that depend on it.
>>>
>>> The reason is that gcc-check-fpatchable-function-entry.sh can fail
>>> if `grep -q` (or scripts/dummy-tools/gcc) is fast enough to exit while
>>> there is still someone writing on other side of pipe. `pipefail`
>>> propagates that error up to kconfig.
>>>
>>> This can be seen for example with:
>>>    # (set -e; set -o pipefail; yes | grep -q y); echo $?
>>>    141
>>>
>>> or by running the actual check script in loop extensively:
>>>    ----------------------------- 8< -------------------------------
>>>    function kconfig()
>>>    {
>>>      for i in `seq 1 100`; do
>>>        arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh \
>>>          ./scripts/dummy-tools/gcc -mlittle-endian \
>>>          || { echo "Oops"; exit 1; }
>>>      done
>>>    }
>>>
>>>    for ((i=0; i<$(nproc); i++)); do kconfig & done
>>>    wait; echo "Done"
>>>    ----------------------------- >8 -------------------------------
>>>
>>> Fixes: 0f71dcfb4aef ("powerpc/ftrace: Add support for -fpatchable-function-entry")
>>> Fixes: b71c9ffb1405 ("powerpc: Add arch/powerpc/tools directory")
>>> Reported-by: Joe Lawrence <joe.lawrence@...hat.com>
>>> Acked-by: Joe Lawrence <joe.lawrence@...hat.com>
>>> Signed-off-by: Jan Stancek <jstancek@...hat.com>
>>> ---
>>>   arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh | 1 -
>>>   arch/powerpc/tools/gcc-check-mprofile-kernel.sh           | 1 -
>>>   2 files changed, 2 deletions(-)
>>>
>>> diff --git a/arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh b/arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh
>>> index 06706903503b..baed467a016b 100755
>>> --- a/arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh
>>> +++ b/arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh
>>> @@ -2,7 +2,6 @@
>>>   # SPDX-License-Identifier: GPL-2.0
>>>
>>>   set -e
>>> -set -o pipefail
>>>
>>>   # To debug, uncomment the following line
>>>   # set -x
>>> diff --git a/arch/powerpc/tools/gcc-check-mprofile-kernel.sh b/arch/powerpc/tools/gcc-check-mprofile-kernel.sh
>>> index 73e331e7660e..6193b0ed0c77 100755
>>> --- a/arch/powerpc/tools/gcc-check-mprofile-kernel.sh
>>> +++ b/arch/powerpc/tools/gcc-check-mprofile-kernel.sh
>>> @@ -2,7 +2,6 @@
>>>   # SPDX-License-Identifier: GPL-2.0
>>>
>>>   set -e
>>> -set -o pipefail
>>>
>>>   # To debug, uncomment the following line
>>>   # set -x
>>> --
>>> 2.47.1
>>
>> Would love to see this picked up, it fixes a problem we have run into
>> with our CI.
>>
>> Tested-by: Justin M. Forbes <jforbes@...oraproject.org>
> 
> Thanks Justin.
> 
> Would any maintainers also care to review? Ty.
> 

Is the problem only with those scripts ? I see other scripts using 
pipefail in the kernel:

arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh:set -o pipefail
arch/powerpc/tools/gcc-check-mprofile-kernel.sh:set -o pipefail
drivers/gpu/drm/ci/dt-binding-check.sh:set -euxo pipefail
drivers/gpu/drm/ci/dtbs-check.sh:set -euxo pipefail
drivers/gpu/drm/ci/kunit.sh:set -euxo pipefail
drivers/gpu/drm/ci/setup-llvm-links.sh:set -euo pipefail
scripts/check-uapi.sh:set -o pipefail

Christophe