kernel/linux.git/scripts/cc-can-link.sh, branch v6.19.11

kbuild: Fix CC_CAN_LINK detection

2026-03-04T12:21:41+00:00

[ Upstream commit be55899b71630c79ad01df54c92e467e47644f87 ] Most samples cannot be build on some environments because they depend on CC_CAN_LINK, which is set according to the result of scripts/cc-can-link.sh called by cc_can_link_user. Because cc-can-link.sh must now build without warning, it may fail because it is calling printf() with an empty string: + cat + gcc -m32 -Werror -Wl,--fatal-warnings -x c - -o /dev/null : In function ‘main’: :4:9: error: zero-length gnu_printf format string [-Werror=format-zero-length] cc1: all warnings being treated as errors Fix this warning and the samples build by actually printing something. Cc: stable@vger.kernel.org Fixes: d81d9d389b9b ("kbuild: don't enable CC_CAN_LINK if the dummy program generates warnings") Signed-off-by: Mickaël Salaün Reviewed-by: Nicolas Schier Reviewed-by: Thomas Weißschuh Link: https://patch.msgid.link/20260212133544.1331437-1-mic@digikod.net Signed-off-by: Nathan Chancellor Signed-off-by: Sasha Levin

kbuild: don't enable CC_CAN_LINK if the dummy program generates warnings

2025-11-14T19:20:34+00:00

It is possible that the kernel toolchain generates warnings when used together with the system toolchain. This happens for example when the older kernel toolchain does not handle new versions of sframe debug information. While these warnings where ignored during the evaluation of CC_CAN_LINK, together with CONFIG_WERROR the actual userprog build will later fail. Example warning: .../x86_64-linux/13.2.0/../../../../x86_64-linux/bin/ld: error in /lib/../lib64/crt1.o(.sframe); no .sframe will be created collect2: error: ld returned 1 exit status Make sure that the very simple example program does not generate warnings already to avoid breaking the userprog compilations. Fixes: ec4a3992bc0b ("kbuild: respect CONFIG_WERROR for linker and assembler") Fixes: 3f0ff4cc6ffb ("kbuild: respect CONFIG_WERROR for userprogs") Signed-off-by: Thomas Weißschuh Reviewed-by: Nicolas Schier Reviewed-by: Nathan Chancellor Link: https://patch.msgid.link/20251114-kbuild-userprogs-bits-v3-1-4dee0d74d439@linutronix.de Signed-off-by: Nicolas Schier

bpfilter: check compiler capability in Kconfig

2018-06-28T04:36:39+00:00

With the brand-new syntax extension of Kconfig, we can directly check the compiler capability in the configuration phase. If the cc-can-link.sh fails, the BPFILTER_UMH is automatically hidden by the dependency. I also deleted 'default n', which is no-op. Signed-off-by: Masahiro Yamada Acked-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller

bpfilter: switch to CC from HOSTCC

2018-06-05T14:21:18+00:00

check that CC can build executables and use that compiler instead of HOSTCC Suggested-by: Arnd Bergmann Signed-off-by: Alexei Starovoitov Signed-off-by: David S. Miller