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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <e8c743dfb16c6c00fd793d7afa6eed33c49f895f.1756202009.git.jstancek@redhat.com>
Date: Tue, 26 Aug 2025 11:54:34 +0200
From: Jan Stancek <jstancek@...hat.com>
To: maddy@...ux.ibm.com,
	mpe@...erman.id.au,
	linuxppc-dev@...ts.ozlabs.org
Cc: npiggin@...il.com,
	christophe.leroy@...roup.eu,
	jstancek@...hat.com,
	linux-kernel@...r.kernel.org,
	joe.lawrence@...hat.com
Subject: [PATCH] powerpc/tools: drop `-o pipefail` in gcc check scripts

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")
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