Based on glibc 2.33 -> 2.34, there is one new feature:
NEWS for version 2.34 =====================
Major new features: * Add _SC_MINSIGSTKSZ and _SC_SIGSTKSZ. When _DYNAMIC_STACK_SIZE_SOURCE or _GNU_SOURCE are defined, MINSIGSTKSZ and SIGSTKSZ are no longer constant on Linux. MINSIGSTKSZ is redefined to sysconf(_SC_MINSIGSTKSZ) and SIGSTKSZ is redefined to sysconf (_SC_SIGSTKSZ). This supports dynamic sized register sets for modern architectural features like Arm SVE.
Build error with the GNU C Library 2.34: DEBUG: | sigreturn.c:150:13: error: variably modified 'altstack_data' at file scope | sigreturn.c:150:13: error: variably modified 'altstack_data' at file scope DEBUG: | 150 | static char altstack_data[SIGSTKSZ]; | 150 | static char altstack_data[SIGSTKSZ]; DEBUG: | | ^~~~~~~~~~~~~
Signed-off-by: Jun Miao jun.miao@windriver.com --- tools/testing/selftests/x86/sigreturn.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/tools/testing/selftests/x86/sigreturn.c b/tools/testing/selftests/x86/sigreturn.c index 57c4f67f16ef..e32ffcc7053d 100644 --- a/tools/testing/selftests/x86/sigreturn.c +++ b/tools/testing/selftests/x86/sigreturn.c @@ -138,9 +138,6 @@ static unsigned short LDT3(int idx) return (idx << 3) | 7; }
-/* Our sigaltstack scratch space. */ -static char altstack_data[SIGSTKSZ]; - static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *), int flags) { @@ -771,7 +768,8 @@ int main() setup_ldt();
stack_t stack = { - .ss_sp = altstack_data, + /* Our sigaltstack scratch space. */ + .ss_sp = malloc (sizeof(char) * SIGSTKSZ), .ss_size = SIGSTKSZ, }; if (sigaltstack(&stack, NULL) != 0) @@ -872,5 +870,6 @@ int main() total_nerrs += test_nonstrict_ss(); #endif
+ free(stack.ss_sp); return total_nerrs ? 1 : 0; }