On 8/23/21 3:30 AM, Jun Miao wrote:

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; }

Please see comments on your v2 that includes this change.

thanks, -- Shuah