diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 71691a8310e77eac2f8061f1bda1e0ece14bc949..0fdbe89d0754058c6d61be12e42134b1a4359045 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -369,12 +369,22 @@ static int putreg(struct task_struct *child,
 	case offsetof(struct user_regs_struct,fs_base):
 		if (value >= TASK_SIZE_MAX)
 			return -EIO;
-		x86_fsbase_write_task(child, value);
+		/*
+		 * When changing the FS base, use do_arch_prctl_64()
+		 * to set the index to zero and to set the base
+		 * as requested.
+		 */
+		if (child->thread.fsbase != value)
+			return do_arch_prctl_64(child, ARCH_SET_FS, value);
 		return 0;
 	case offsetof(struct user_regs_struct,gs_base):
+		/*
+		 * Exactly the same here as the %fs handling above.
+		 */
 		if (value >= TASK_SIZE_MAX)
 			return -EIO;
-		x86_gsbase_write_task(child, value);
+		if (child->thread.gsbase != value)
+			return do_arch_prctl_64(child, ARCH_SET_GS, value);
 		return 0;
 #endif
 	}
diff --git a/tools/testing/selftests/x86/fsgsbase.c b/tools/testing/selftests/x86/fsgsbase.c
index 5ab4c60c100e3dba810b26eb33dd0813fb1f3ac6..15a329da59fa3086e1e2f93b5055c40c3b75028b 100644
--- a/tools/testing/selftests/x86/fsgsbase.c
+++ b/tools/testing/selftests/x86/fsgsbase.c
@@ -489,25 +489,11 @@ static void test_ptrace_write_gsbase(void)
 		 * selector value is changed or not by the GSBASE write in
 		 * a ptracer.
 		 */
-		if (gs != *shared_scratch) {
-			nerrs++;
-			printf("[FAIL]\tGS changed to %lx\n", gs);
-
-			/*
-			 * On older kernels, poking a nonzero value into the
-			 * base would zero the selector.  On newer kernels,
-			 * this behavior has changed -- poking the base
-			 * changes only the base and, if FSGSBASE is not
-			 * available, this may have no effect.
-			 */
-			if (gs == 0)
-				printf("\tNote: this is expected behavior on older kernels.\n");
-		} else if (have_fsgsbase && (base != 0xFF)) {
-			nerrs++;
-			printf("[FAIL]\tGSBASE changed to %lx\n", base);
+		if (gs == 0 && base == 0xFF) {
+			printf("[OK]\tGS was reset as expected\n");
 		} else {
-			printf("[OK]\tGS remained 0x%hx%s", *shared_scratch, have_fsgsbase ? " and GSBASE changed to 0xFF" : "");
-			printf("\n");
+			nerrs++;
+			printf("[FAIL]\tGS=0x%lx, GSBASE=0x%lx (should be 0, 0xFF)\n", gs, base);
 		}
 	}