On Wed, Feb 12, 2025, at 15:29, Naresh Kamboju wrote:
The kselftest-vDSO/vdso_test_abi test encounters failures when built and executed using GCC-13 on armv7 architecture. The issue has been observed on both TI X15 devices and QEMU-armv7.
Interestingly, the same test passes without any issues when built using Clang-19.This failure is specific to GCC-13. but test case should have been failed on clang toolchain but it did not.
To clarify: the failure depends on how the toolchain is built: for compilers using the default 32-bit time_t in glibc, ltp does not notice a problem, but using gcc it will run into a testcase bug because the vdso_test_abi.c file incorrectly mixes libc types and kernel types.
The Clang toolchain likely defaults to the traditional 32-bit time_t on 32-bit Debian Trixie (except x86), leading to an ABI issue similar to older compilers. This is affecting compatibility.
This is not a new regression, this report generated on Linux next but also seen on Linux stable tree.
Test name: kselftest-vDSO/vdso_test_abi Fails: gcc-13 pass: clang-19
Arnd Bergmann investigated and proposed a patch which fixes the problem.
The patch only makes changes ltp so it tests the old system calls correctly regardless of the toolchain settings.
Someone still needs to change LTP to include this change as well as add tests for the 64-bit time_t vdso functions.
Arnd