Commit 29dc539d authored by Sean Christopherson's avatar Sean Christopherson
Browse files

KVM: selftests: Report stacktraces SIGBUS, SIGSEGV, SIGILL, and SIGFPE by default 



Register handlers for signals for all selftests that are likely happen due
to test (or kernel) bugs, and explicitly fail tests on unexpected signals
so that users get a stack trace, i.e. don't have to go spelunking to do
basic triage.

Register the handlers as early as possible, to catch as many unexpected
signals as possible, and also so that the common code doesn't clobber a
handler that's installed by test (or arch) code.

Tested-by: default avatarAckerley Tng <ackerleytng@google.com>
Reviewed-by: default avatarAckerley Tng <ackerleytng@google.com>
Reviewed-by: default avatarShivank Garg <shivankg@amd.com>
Tested-by: default avatarShivank Garg <shivankg@amd.com>
Link: https://lore.kernel.org/r/20251016172853.52451-8-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 3223560c

tools/testing/selftests/kvm/lib/kvm_util.c

+24 −0
Original line number Diff line number Diff line
@@ -2290,11 +2290,35 @@ __weak void kvm_selftest_arch_init(void) 
{

}



static void report_unexpected_signal(int signum)

{

#define KVM_CASE_SIGNUM(sig)					\

	case sig: TEST_FAIL("Unexpected " #sig " (%d)\n", signum)



	switch (signum) {

	KVM_CASE_SIGNUM(SIGBUS);

	KVM_CASE_SIGNUM(SIGSEGV);

	KVM_CASE_SIGNUM(SIGILL);

	KVM_CASE_SIGNUM(SIGFPE);

	default:

		TEST_FAIL("Unexpected signal %d\n", signum);

	}

}



void __attribute((constructor)) kvm_selftest_init(void)

{

	struct sigaction sig_sa = {

		.sa_handler = report_unexpected_signal,

	};



	/* Tell stdout not to buffer its content. */

	setbuf(stdout, NULL);



	sigaction(SIGBUS, &sig_sa, NULL);

	sigaction(SIGSEGV, &sig_sa, NULL);

	sigaction(SIGILL, &sig_sa, NULL);

	sigaction(SIGFPE, &sig_sa, NULL);



	guest_random_seed = last_guest_seed = random();

	pr_info("Random seed: 0x%x\n", guest_random_seed);