diff --git a/risu.c b/risu.c
index 714074e..36fc82a 100644
--- a/risu.c
+++ b/risu.c
@@ -106,14 +106,14 @@ static void respond(RisuResult r)
     }
 }
 
-static RisuResult send_register_info(void *uc)
+static RisuResult send_register_info(void *uc, void *siaddr)
 {
     uint64_t paramreg;
     RisuResult res;
     RisuOp op;
     void *extra;
 
-    reginfo_init(&ri[MASTER], uc);
+    reginfo_init(&ri[MASTER], uc, siaddr);
     op = get_risuop(&ri[MASTER]);
 
     /* Write a header with PC/op to keep in sync */
@@ -178,7 +178,7 @@ static void master_sigill(int sig, siginfo_t *si, void *uc)
     RisuResult r;
     signal_count++;
 
-    r = send_register_info(uc);
+    r = send_register_info(uc, si->si_addr);
     if (r == RES_OK) {
         advance_pc(uc);
     } else {
@@ -232,13 +232,13 @@ static RisuResult recv_register_info(struct reginfo *ri)
     }
 }
 
-static RisuResult recv_and_compare_register_info(void *uc)
+static RisuResult recv_and_compare_register_info(void *uc, void *siaddr)
 {
     uint64_t paramreg;
     RisuResult res;
     RisuOp op;
 
-    reginfo_init(&ri[APPRENTICE], uc);
+    reginfo_init(&ri[APPRENTICE], uc, siaddr);
 
     res = recv_register_info(&ri[MASTER]);
     if (res != RES_OK) {
@@ -315,7 +315,7 @@ static void apprentice_sigill(int sig, siginfo_t *si, void *uc)
     RisuResult r;
     signal_count++;
 
-    r = recv_and_compare_register_info(uc);
+    r = recv_and_compare_register_info(uc, si->si_addr);
     if (r == RES_OK) {
         advance_pc(uc);
     } else {
diff --git a/risu.h b/risu.h
index bdb70c1..2c43384 100644
--- a/risu.h
+++ b/risu.h
@@ -115,7 +115,7 @@ RisuOp get_risuop(struct reginfo *ri);
 uintptr_t get_pc(struct reginfo *ri);
 
 /* initialize structure from a ucontext */
-void reginfo_init(struct reginfo *ri, ucontext_t *uc);
+void reginfo_init(struct reginfo *ri, ucontext_t *uc, void *siaddr);
 
 /* return 1 if structs are equal, 0 otherwise. */
 int reginfo_is_eq(struct reginfo *r1, struct reginfo *r2);
diff --git a/risu_reginfo_aarch64.c b/risu_reginfo_aarch64.c
index be47980..1244454 100644
--- a/risu_reginfo_aarch64.c
+++ b/risu_reginfo_aarch64.c
@@ -82,7 +82,7 @@ int reginfo_size(struct reginfo *ri)
 }
 
 /* reginfo_init: initialize with a ucontext */
-void reginfo_init(struct reginfo *ri, ucontext_t *uc)
+void reginfo_init(struct reginfo *ri, ucontext_t *uc, void *siaddr)
 {
     int i;
     struct _aarch64_ctx *ctx, *extra = NULL;
diff --git a/risu_reginfo_arm.c b/risu_reginfo_arm.c
index 202120b..85a39ac 100644
--- a/risu_reginfo_arm.c
+++ b/risu_reginfo_arm.c
@@ -118,7 +118,7 @@ static void reginfo_init_vfp(struct reginfo *ri, ucontext_t *uc)
     }
 }
 
-void reginfo_init(struct reginfo *ri, ucontext_t *uc)
+void reginfo_init(struct reginfo *ri, ucontext_t *uc, void *siaddr)
 {
     memset(ri, 0, sizeof(*ri));         /* necessary for memcmp later */
 
diff --git a/risu_reginfo_i386.c b/risu_reginfo_i386.c
index e9730be..834b2ed 100644
--- a/risu_reginfo_i386.c
+++ b/risu_reginfo_i386.c
@@ -102,7 +102,7 @@ static void *xsave_feature_buf(struct _xstate *xs, int feature)
 }
 
 /* reginfo_init: initialize with a ucontext */
-void reginfo_init(struct reginfo *ri, ucontext_t *uc)
+void reginfo_init(struct reginfo *ri, ucontext_t *uc, void *siaddr)
 {
     int i, nvecregs;
     struct _fpstate *fp;
diff --git a/risu_reginfo_loongarch64.c b/risu_reginfo_loongarch64.c
index af6ab77..16384f1 100644
--- a/risu_reginfo_loongarch64.c
+++ b/risu_reginfo_loongarch64.c
@@ -81,7 +81,7 @@ static int parse_extcontext(struct sigcontext *sc, struct extctx_layout *extctx)
 }
 
 /* reginfo_init: initialize with a ucontext */
-void reginfo_init(struct reginfo *ri, ucontext_t *context)
+void reginfo_init(struct reginfo *ri, ucontext_t *context, void *siaddr)
 {
     int i;
     struct ucontext *uc = (struct ucontext *)context;
diff --git a/risu_reginfo_m68k.c b/risu_reginfo_m68k.c
index 4c25e77..e29da84 100644
--- a/risu_reginfo_m68k.c
+++ b/risu_reginfo_m68k.c
@@ -33,7 +33,7 @@ int reginfo_size(struct reginfo *ri)
 }
 
 /* reginfo_init: initialize with a ucontext */
-void reginfo_init(struct reginfo *ri, ucontext_t *uc)
+void reginfo_init(struct reginfo *ri, ucontext_t *uc, void *siaddr)
 {
     int i;
     memset(ri, 0, sizeof(*ri));
diff --git a/risu_reginfo_ppc64.c b/risu_reginfo_ppc64.c
index 9899b36..bbdd63c 100644
--- a/risu_reginfo_ppc64.c
+++ b/risu_reginfo_ppc64.c
@@ -42,7 +42,7 @@ int reginfo_size(struct reginfo *ri)
 }
 
 /* reginfo_init: initialize with a ucontext */
-void reginfo_init(struct reginfo *ri, ucontext_t *uc)
+void reginfo_init(struct reginfo *ri, ucontext_t *uc, void *siaddr)
 {
     int i;
 
