On 2026-10-14 16:01:27-0400, Sasha Levin wrote: > get_size provides its own _start and is linked statically against the C > library with -nostartfiles. That combination assumes startup and TLS > details that vary between architectures and C library versions: errno > lives in thread-local storage that is never set up, and the static link > expects symbols from the skipped startup files. CI builds have failed > with undefined _init/_fini on ARM with clang and an undefined _DYNAMIC > on LoongArch.
I get the _DYNAMIC failures even on my boring x86_64 distro setup. > Build the test with the in-tree nolibc instead. nolibc provides the > startup code, so the test returns from main(), and it provides the > write() and syscall() wrappers without the TLS errno problem. A failing > sysinfo() is now reported as a TAP failure instead of crashing the > test. Keep the static link and the existing TAP output. > > Since the test no longer uses the system C library headers, the kernel > UAPI headers have to be installed before it is built. Add the headers > target as an order-only prerequisite, as nolibc-test does, so that a > standalone build installs them. Link libgcc only when the selected > compiler is GCC, which needs it for division helpers on ARM, and detect > that from the compiler rather than from LLVM so that CC=clang builds do > not try to link a libgcc that clang does not provide. > > nolibc does not support arc, csky, microblaze, nios2 or xtensa, yet... > so the > test can no longer be built for those architectures. This conversion > also makes the separate i386 vDSO workaround proposed for get_size > unnecessary. Nobody seems to build the selftests for these architectures anyways. > Link: https://lore.kernel.org/r/[email protected] > Fixes: 3ce51050fadd ("selftest: size: Add size test for Linux kernel") > Cc: [email protected] # 6.18.x I am not so excited about Fixes and Cc: stable. But if it breaks, it will land on your plate anyways :-) > Signed-off-by: Sasha Levin <[email protected]> Reviewed-by: Thomas Weißschuh <[email protected]> > --- > tools/testing/selftests/size/Makefile | 9 ++++++- > tools/testing/selftests/size/get_size.c | 33 +++++++------------------ > 2 files changed, 17 insertions(+), 25 deletions(-) (...) > --- a/tools/testing/selftests/size/get_size.c > +++ b/tools/testing/selftests/size/get_size.c (...) > -#include <sys/sysinfo.h> > -#include <unistd.h> > -#include <sys/syscall.h> > - > -#define STDOUT_FILENO 1 > +#include <nolibc.h> Note: The newfangled way to use nolibc would be to stick to the regular libc includes: #include <unistd.h> #include <sys/syscall.h> #include <linux/sysinfo.h> But what you have also works, obviously. > +#include <linux/sysinfo.h> (...)
