printsiginfo: print si_addr_lsb for BUS_MCEERR_A[RO] signals

* configure.ac (AC_CHECK_MEMBERS): Add siginfo_t.si_addr_lsb check.
* src/printsiginfo.c (print_si_info) [!BUS_OPFETCH
&& HAVE_SIGINFO_T_SI_ADDR_LSB] <case SIGBUS>: Print si_addr_lsb field
is si_code is equal to BUS_MCEERR_AR or BUS_MCEERR_AO.
* tests/ptrace.c: Add checks.
* NEWS: Mention it.

4 files changed, 54 insertions, 7 deletions

diff --git a/NEWS b/NEWS
index bef4f5650..c59a53a4c 100644
--- a/NEWS
+++ b/NEWS
@@ -15,6 +15,7 @@ Noteworthy changes in release ?.?? (????-??-??)
     INET_DIAG_PROTOCOL, INET_DIAG_REQ_PROTOCOL, INET_DIAG_SHUTDOWN,
     INET_DIAG_SK_BPF_STORAGES, INET_DIAG_SOCKOPT, and INET_DIAG_ULP_INFO
     NETLINK_SOCK_DIAG netlink attributes.
+  * Enhanced siginfo_t decoding.
   * Updated decoding of struct rtnl_link_stats64.
   * Updated lists of DEVCONF_*, FAN_MARK_*, GPIO_V2_LINE_FLAG_*, IORING_*,
     KEXEC_*, LANDLOCK_*, NET_IPV4_CONF_*, NLM_F_*, NT_*, PR_*, SECCOMP_*,
diff --git a/configure.ac b/configure.ac
index 51f27b186..30dab8eea 100644
--- a/configure.ac
+++ b/configure.ac
@@ -424,7 +424,8 @@ AC_CHECK_MEMBERS(m4_normalize([
 	siginfo_t.si_syscall,
 	siginfo_t.si_timerid,
 	siginfo_t.si_overrun,
-	siginfo_t.si_pkey
+	siginfo_t.si_pkey,
+	siginfo_t.si_addr_lsb
 ]),,, [#include <signal.h>])
 
 AC_CHECK_HEADERS(m4_normalize([
diff --git a/src/printsiginfo.c b/src/printsiginfo.c
index 083845ec1..c49bf0163 100644
--- a/src/printsiginfo.c
+++ b/src/printsiginfo.c
@@ -166,6 +166,15 @@ print_si_info(struct tcb *tcp, const siginfo_t *sip)
 		case SIGBUS:
 			tprint_struct_next();
 			PRINT_FIELD_PTR(*sip, si_addr);
+#if !defined(BUS_OPFETCH) && defined(HAVE_SIGINFO_T_SI_ADDR_LSB)
+			switch (sip->si_code) {
+			case BUS_MCEERR_AR:
+			case BUS_MCEERR_AO:
+				tprint_struct_next();
+				PRINT_FIELD_X(*sip, si_addr_lsb);
+				break;
+			}
+#endif /* !BUS_OPFETCH && HAVE_SIGINFO_T_SI_ADDR_LSB */
 			break;
 		case SIGSEGV:
 			tprint_struct_next();
diff --git a/tests/ptrace.c b/tests/ptrace.c
index 00d8807d9..c22403ec9 100644
--- a/tests/ptrace.c
+++ b/tests/ptrace.c
@@ -33,6 +33,12 @@
 #undef XLAT_MACROS_ONLY
 #include "xlat/audit_arch.h"
 
+struct valstraux {
+	int val;
+	const char *str;
+	const char *aux;
+};
+
 static const char *errstr;
 
 static long
@@ -1827,18 +1833,48 @@ main(void)
 	       XLAT_ARGS(SIGFPE), XLAT_ARGS(FPE_INTDIV), XLAT_ARGS(ENOENT),
 	       sip->si_addr, errstr);
 
+	/* SIGBUS */
+	struct valstraux bus_codes[] = {
+		{ ARG_XLAT_KNOWN(0x1, "BUS_ADRALN") },
+		{ ARG_XLAT_KNOWN(0x2, "BUS_ADRERR") },
+		{ ARG_XLAT_KNOWN(0x3, "BUS_OBJERR") },
+#ifdef BUS_OPFETCH
+		{ ARG_XLAT_KNOWN(0x4, "BUS_OPFETCH") },
+#else
+		{ ARG_XLAT_KNOWN(0x4, "BUS_MCEERR_AR"),
+# ifdef HAVE_SIGINFO_T_SI_ADDR_LSB
+		  ", si_addr_lsb=0xdead"
+# endif
+		},
+#endif
+		{ ARG_XLAT_KNOWN(0x5, "BUS_MCEERR_AO"),
+# if !defined(BUS_OPFETCH) && defined(HAVE_SIGINFO_T_SI_ADDR_LSB)
+		  ", si_addr_lsb=0xdead"
+# endif
+		},
+		{ ARG_STR(0x6) },
+		{ ARG_STR(0x499602d2) },
+	};
+
 	memset(sip, -1, sizeof(*sip));
 	sip->si_signo = SIGBUS;
 	sip->si_code = 1;
 	sip->si_errno = -2;
 	sip->si_addr = (void *) (unsigned long) 0xfacefeeddeadbeefULL;
+#ifdef HAVE_SIGINFO_T_SI_ADDR_LSB
+	sip->si_addr_lsb = 0xdead;
+#endif
+	for (size_t i = 0; i < ARRAY_SIZE(bus_codes); i++) {
+		sip->si_code = bus_codes[i].val;
 
-	do_ptrace(PTRACE_SETSIGINFO, pid, bad_request, (uintptr_t) sip);
-	printf("ptrace(" XLAT_FMT ", %d, %#lx, {si_signo=" XLAT_FMT_U
-	       ", si_code=" XLAT_FMT ", si_errno=%u, si_addr=%p}) = %s\n",
-	       XLAT_ARGS(PTRACE_SETSIGINFO), pid, bad_request,
-	       XLAT_ARGS(SIGBUS), XLAT_ARGS(BUS_ADRALN),
-	       sip->si_errno, sip->si_addr, errstr);
+		do_ptrace(PTRACE_SETSIGINFO, pid, bad_request, (uintptr_t) sip);
+		printf("ptrace(" XLAT_FMT ", %d, %#lx, {si_signo=" XLAT_FMT_U
+		       ", si_code=%s, si_errno=%u, si_addr=%p%s}) = %s\n",
+		       XLAT_ARGS(PTRACE_SETSIGINFO), pid, bad_request,
+		       XLAT_ARGS(SIGBUS), bus_codes[i].str,
+		       sip->si_errno, sip->si_addr, bus_codes[i].aux ?: "",
+		       errstr);
+	}
 
 	memset(sip, -1, sizeof(*sip));
 	sip->si_signo = SIGPROF;