On Mon, Feb 03, 2025 at 12:35:42PM +0200, Dmitry V. Levin wrote:
> On Mon, Feb 03, 2025 at 10:29:37AM +0100, Alexander Gordeev wrote:
> > On Mon, Feb 03, 2025 at 08:58:49AM +0200, Dmitry V. Levin wrote:
> >
> > Hi Dmitry,
> >
> > > PTRACE_SET_SYSCALL_INFO is a generic ptrace API that complements
> > > PTRACE_GET_SYSCALL_INFO by letting the ptracer modify details of
> > > system calls the tracee is blocked in.
> > ...
> >
> > FWIW, I am getting these on s390:
> >
> > # ./tools/testing/selftests/ptrace/set_syscall_info
> > TAP version 13
> > 1..1
> > # Starting 1 tests from 1 test cases.
> > # RUN global.set_syscall_info ...
> > # set_syscall_info.c:87:set_syscall_info:Expected exp_entry->nr (-1) == info->entry.nr (65535)
> > # set_syscall_info.c:88:set_syscall_info:wait #3: PTRACE_GET_SYSCALL_INFO #2: syscall nr mismatch
> > # set_syscall_info: Test terminated by assertion
> > # FAIL global.set_syscall_info
> > not ok 1 global.set_syscall_info
> > # FAILED: 0 / 1 tests passed.
> > # Totals: pass:0 fail:1 xfail:0 xpass:0 skip:0 error:0
> >
> > I remember one of the earlier versions (v1 or v2) was working for me.
> >
> > Thanks!
>
> In v3, this test was extended to check whether PTRACE_GET_SYSCALL_INFO
> called immediately after PTRACE_SET_SYSCALL_INFO returns the same syscall
> number, and on s390 it apparently doesn't, thanks to its implementation
> of syscall_get_nr() that returns 0xffff in this case.
>
> To workaround this, we could either change syscall_get_nr() to return -1
> in this case, or add an #ifdef __s390x__ exception to the test.
>
> What would you prefer?
OK, I'm going to apply the following s390 workaround to the test:
diff --git a/tools/testing/selftests/ptrace/set_syscall_info.c b/tools/testing/selftests/ptrace/set_syscall_info.c
index 0ec69401c008..4198248ef874 100644
--- a/tools/testing/selftests/ptrace/set_syscall_info.c
+++ b/tools/testing/selftests/ptrace/set_syscall_info.c
@@ -71,6 +71,11 @@ check_psi_entry(struct __test_metadata *_metadata,
const char *text)
{
unsigned int i;
+ int exp_nr = exp_entry->nr;
+#if defined __s390__ || defined __s390x__
+ /* s390 is the only architecture that has 16-bit syscall numbers */
+ exp_nr &= 0xffff;
+#endif
ASSERT_EQ(PTRACE_SYSCALL_INFO_ENTRY, info->op) {
LOG_KILL_TRACEE("%s: entry stop mismatch", text);
@@ -84,7 +89,7 @@ check_psi_entry(struct __test_metadata *_metadata,
ASSERT_TRUE(info->stack_pointer) {
LOG_KILL_TRACEE("%s: entry stop mismatch", text);
}
- ASSERT_EQ(exp_entry->nr, info->entry.nr) {
+ ASSERT_EQ(exp_nr, info->entry.nr) {
LOG_KILL_TRACEE("%s: syscall nr mismatch", text);
}
for (i = 0; i < ARRAY_SIZE(exp_entry->args); ++i) {
--
ldv
