Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 198ee8e1 authored by Dominik Brodowski's avatar Dominik Brodowski Committed by Ingo Molnar
Browse files

selftests/x86: Fix vDSO selftest segfault for vsyscall=none 



The vDSO selftest tries to execute a vsyscall unconditionally, even if it
is not present on the test system (e.g. if booted with vsyscall=none or
with CONFIG_LEGACY_VSYSCALL_NONE=y set. Fix this by copying (and tweaking)
the vsyscall check from test_vsyscall.c

Signed-off-by: default avatarDominik Brodowski <linux@dominikbrodowski.net>
Cc: Andrew Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kselftest@vger.kernel.org
Cc: shuah@kernel.org
Link: http://lkml.kernel.org/r/20180211111013.16888-3-linux@dominikbrodowski.net


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent b498c261

tools/testing/selftests/x86/test_vdso.c

+43 −7
Original line number Original line Diff line number Diff line
@@ -28,18 +28,52 @@ 




int nerrs = 0;

int nerrs = 0;





typedef long (*getcpu_t)(unsigned *, unsigned *, void *);



getcpu_t vgetcpu;

getcpu_t vdso_getcpu;



static void *vsyscall_getcpu(void)

{

#ifdef __x86_64__

#ifdef __x86_64__

# define VSYS(x) (x)

	FILE *maps;

	char line[128];

	bool found = false;



	maps = fopen("/proc/self/maps", "r");

	if (!maps) /* might still be present, but ignore it here, as we test vDSO not vsyscall */

		return NULL;



	while (fgets(line, sizeof(line), maps)) {

		char r, x;

		void *start, *end;

		char name[128];

		if (sscanf(line, "%p-%p %c-%cp %*x %*x:%*x %*u %s",

			   &start, &end, &r, &x, name) != 5)

			continue;



		if (strcmp(name, "[vsyscall]"))

			continue;



		/* assume entries are OK, as we test vDSO here not vsyscall */

		found = true;

		break;

	}



	fclose(maps);



	if (!found) {

		printf("Warning: failed to find vsyscall getcpu\n");

		return NULL;

	}

	return (void *) (0xffffffffff600800);

#else

#else

# define VSYS(x) 0

	return NULL;

#endif

#endif

}





typedef long (*getcpu_t)(unsigned *, unsigned *, void *);



const getcpu_t vgetcpu = (getcpu_t)VSYS(0xffffffffff600800);

getcpu_t vdso_getcpu;





void fill_function_pointers()

static void fill_function_pointers()

{

{

	void *vdso = dlopen("linux-vdso.so.1",

	void *vdso = dlopen("linux-vdso.so.1",

			    RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);

			    RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD);
@@ -54,6 +88,8 @@ void fill_function_pointers() 
	vdso_getcpu = (getcpu_t)dlsym(vdso, "__vdso_getcpu");

	vdso_getcpu = (getcpu_t)dlsym(vdso, "__vdso_getcpu");

	if (!vdso_getcpu)

	if (!vdso_getcpu)

		printf("Warning: failed to find getcpu in vDSO\n");

		printf("Warning: failed to find getcpu in vDSO\n");



	vgetcpu = (getcpu_t) vsyscall_getcpu();

}

}





static long sys_getcpu(unsigned * cpu, unsigned * node,

static long sys_getcpu(unsigned * cpu, unsigned * node,