when running strace tests, we noticed that si_addr appears to be wrong. the attached test shows the problem -- si_addr isn't set to the faulting address. i hacked arch/s390/mm/fault.c:do_sigsegv to load regs->psw.addr (sans mask), and it worked for insn based crashes. but obviously that doesn't work for data based ones. i'm not familiar with how regs->int_parm_long works though, so maybe it's supposed to be loaded indirectly. the use of __FAIL_ADDR_MASK blindly is most certainly incorrect ... whatever the fix, do_sigbus probably needs it too. on x86_64, both work: $ gcc test.c -O3 $ ./a.out data crash received signal 11 si_addr 0xa0 crasher 0xa0 PASS $ ./a.out asdf text crash received signal 11 si_addr 0xa0 crasher 0xa0 PASS on s390 both fail: $ gcc test.c -O3 $ ./a.out data crash received signal 11 si_addr (nil) crasher 0xa0 FAIL $ ./a.out asdf text crash received signal 11 si_addr (nil) crasher 0xa0 FAIL -mike
#include <inttypes.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
static bool text = true;
union {
void (*fn)(void);
uintptr_t ptr;
} crasher;
static int *ptr;
__attribute__((__noinline__))
void crashit(void)
{
if (text) {
crasher.ptr = 0xA0;
crasher.fn();
} else {
ptr = (void *)0xA0;
*ptr = 1;
}
}
void sigcatcher(int signum, siginfo_t *siginfo, void *ucontext)
{
printf("received signal %i\n", signum);
if (signum != SIGSEGV) {
puts("FAIL (not SIGSEGV)");
exit(2);
}
printf("si_addr %p\n", siginfo->si_addr);
bool passed;
if (text) {
printf("crasher %p\n", crasher.fn);
passed = (crasher.ptr == (uintptr_t)siginfo->si_addr);
} else {
printf("crasher %p\n", ptr);
passed = (ptr == siginfo->si_addr);
}
if (passed) {
puts("PASS");
exit(0);
} else {
puts("FAIL");
exit(1);
}
}
int main(int argc, char *argv[])
{
struct sigaction sa;
sa.sa_flags = SA_RESTART | SA_SIGINFO;
sa.sa_sigaction = sigcatcher;
sigaction(SIGSEGV, &sa, NULL);
text = argc > 1 ? true : false;
puts(text ? "text crash" : "data crash");
crashit();
return 10;
}
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