--- valgrind-3.7.0/coregrind/m_syswrap/syswrap-linux.c.orig 2011-11-24 17:37:50.029324690 -0200 +++ valgrind-3.7.0/coregrind/m_syswrap/syswrap-linux.c 2011-11-24 17:38:24.057324639 -0200 @@ -2109,8 +2109,9 @@ PRE(sys_capget) vki_cap_user_header_t, header, vki_cap_user_data_t, data); PRE_MEM_READ( "capget(header)", ARG1, sizeof(struct __vki_user_cap_header_struct) ); - PRE_MEM_WRITE( "capget(data)", ARG2, - sizeof(struct __vki_user_cap_data_struct) ); + if (ARG2 != (Addr)NULL) + PRE_MEM_WRITE( "capget(data)", ARG2, + sizeof(struct __vki_user_cap_data_struct) ); } POST(sys_capget) {