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@xxxxxxxxxxxxx>
---
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
