diff --git a/arch/m68k/kernel/signal.c b/arch/m68k/kernel/signal.c
index e79421f5b9cd..f7cd5ecfacd3 100644
--- a/arch/m68k/kernel/signal.c
+++ b/arch/m68k/kernel/signal.c
@@ -574,6 +574,66 @@ static inline int rt_save_fpu_state(struct ucontext __user *uc, struct pt_regs *
 
 #endif /* CONFIG_FPU */
 
+static inline void siginfo_build_tests(void)
+{
+	/* This needs to be tested on m68k as it has a lesser
+	 * alignment requirment than x86 and that can cause surprises.
+	 */
+
+	/* This is part of the ABI and can never change in size: */
+	BUILD_BUG_ON(sizeof(siginfo_t) != 128);
+
+	/* Ensure the know fields never change in location */
+	BUILD_BUG_ON(offsetof(siginfo_t, si_signo) != 0);
+	BUILD_BUG_ON(offsetof(siginfo_t, si_errno) != 4);
+	BUILD_BUG_ON(offsetof(siginfo_t, si_code)  != 8);
+
+	/* _kill */
+	BUILD_BUG_ON(offsetof(siginfo_t, si_pid) != 0x0C);
+	BUILD_BUG_ON(offsetof(siginfo_t, si_uid) != 0x10);
+
+	/* _timer */
+	BUILD_BUG_ON(offsetof(siginfo_t, si_tid)     != 0x0C);
+	BUILD_BUG_ON(offsetof(siginfo_t, si_overrun) != 0x10);
+	BUILD_BUG_ON(offsetof(siginfo_t, si_value)   != 0x14);
+
+	/* _rt */
+	BUILD_BUG_ON(offsetof(siginfo_t, si_pid)   != 0x0C);
+	BUILD_BUG_ON(offsetof(siginfo_t, si_uid)   != 0x10);
+	BUILD_BUG_ON(offsetof(siginfo_t, si_value) != 0x14);
+
+	/* _sigchld */
+	BUILD_BUG_ON(offsetof(siginfo_t, si_pid)    != 0x0C);
+	BUILD_BUG_ON(offsetof(siginfo_t, si_uid)    != 0x10);
+	BUILD_BUG_ON(offsetof(siginfo_t, si_status) != 0x14);
+	BUILD_BUG_ON(offsetof(siginfo_t, si_utime)  != 0x18);
+	BUILD_BUG_ON(offsetof(siginfo_t, si_stime)  != 0x1C);
+
+	/* _sigfault */
+	BUILD_BUG_ON(offsetof(siginfo_t, si_addr) != 0x0C);
+
+	/* _sigfault._mcerr */
+	BUILD_BUG_ON(offsetof(siginfo_t, si_addr_lsb) != 0x10);
+
+	/* _sigfault._addr_bnd */
+	BUILD_BUG_ON(offsetof(siginfo_t, si_lower) != 0x12);
+	BUILD_BUG_ON(offsetof(siginfo_t, si_upper) != 0x16);
+
+	/* _sigfault._addr_pkey */
+	BUILD_BUG_ON(offsetof(siginfo_t, si_pkey) != 0x12);
+
+	/* _sigpoll */
+	BUILD_BUG_ON(offsetof(siginfo_t, si_band)   != 0x0C);
+	BUILD_BUG_ON(offsetof(siginfo_t, si_fd)     != 0x10);
+
+	/* _sigsys */
+	BUILD_BUG_ON(offsetof(siginfo_t, si_call_addr) != 0x0C);
+	BUILD_BUG_ON(offsetof(siginfo_t, si_syscall)   != 0x10);
+	BUILD_BUG_ON(offsetof(siginfo_t, si_arch)      != 0x14);
+
+	/* any new si_fields should be added here */
+}
+
 static int mangle_kernel_stack(struct pt_regs *regs, int formatvec,
 			       void __user *fp)
 {
@@ -635,6 +695,8 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *usc, void __u
 	struct sigcontext context;
 	int err = 0;
 
+	siginfo_build_tests();
+
 	/* Always make any pending restarted system calls return -EINTR */
 	current->restart_block.fn = do_no_restart_syscall;
 
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 9847c5a013c3..f188eab10570 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -226,6 +226,8 @@ typedef struct compat_siginfo {
 #ifdef __ARCH_SI_TRAPNO
 			int _trapno;	/* TRAP # which caused the signal */
 #endif
+#define __COMPAT_ADDR_BND_PKEY_PAD  (__alignof__(compat_uptr_t) < sizeof(short) ? \
+				     sizeof(short) : __alignof__(compat_uptr_t))
 			union {
 				/*
 				 * used when si_code=BUS_MCEERR_AR or
@@ -234,13 +236,13 @@ typedef struct compat_siginfo {
 				short int _addr_lsb;	/* Valid LSB of the reported address. */
 				/* used when si_code=SEGV_BNDERR */
 				struct {
-					compat_uptr_t _dummy_bnd;
+					char _dummy_bnd[__COMPAT_ADDR_BND_PKEY_PAD];
 					compat_uptr_t _lower;
 					compat_uptr_t _upper;
 				} _addr_bnd;
 				/* used when si_code=SEGV_PKUERR */
 				struct {
-					compat_uptr_t _dummy_pkey;
+					char _dummy_pkey[__COMPAT_ADDR_BND_PKEY_PAD];
 					u32 _pkey;
 				} _addr_pkey;
 			};
diff --git a/include/uapi/asm-generic/siginfo.h b/include/uapi/asm-generic/siginfo.h
index 6088bca89917..544208fd3db1 100644
--- a/include/uapi/asm-generic/siginfo.h
+++ b/include/uapi/asm-generic/siginfo.h
@@ -94,6 +94,9 @@ typedef struct siginfo {
 			unsigned int _flags;	/* see ia64 si_flags */
 			unsigned long _isr;	/* isr */
 #endif
+
+#define __ADDR_BND_PKEY_PAD  (__alignof__(void *) < sizeof(short) ? \
+			      sizeof(short) : __alignof__(void *))
 			union {
 				/*
 				 * used when si_code=BUS_MCEERR_AR or
@@ -102,13 +105,13 @@ typedef struct siginfo {
 				short _addr_lsb; /* LSB of the reported address */
 				/* used when si_code=SEGV_BNDERR */
 				struct {
-					void *_dummy_bnd;
+					char _dummy_bnd[__ADDR_BND_PKEY_PAD];
 					void __user *_lower;
 					void __user *_upper;
 				} _addr_bnd;
 				/* used when si_code=SEGV_PKUERR */
 				struct {
-					void *_dummy_pkey;
+					char _dummy_pkey[__ADDR_BND_PKEY_PAD];
 					__u32 _pkey;
 				} _addr_pkey;
 			};