sigaction.2: Document SEGV_BNDERR

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man2/sigaction.2

@@ -299,6 +299,10 @@ siginfo_t {
     int      si_fd;        /* File descriptor */
     short    si_addr_lsb;  /* Least significant bit of address
                               (since Linux 2.6.32) */
+    void    *si_lower;     /* Lower bound when address violation
+                              occurred (since Linux 3.19) */
+    void    *si_upper;     /* Upper bound when address violation
+                              occurred (since Linux 3.19) */
     void    *si_call_addr; /* Address of system call instruction
                               (since Linux 3.5) */
     int      si_syscall;   /* Number of attempted system call
@@ -456,6 +460,15 @@ the tracee will be shown as delivering the event.
 and
 .I si_addr_lsb
 are Linux-specific extensions.
+
+The
+.BR SEGV_BNDERR
+suberror of
+.B SIGSEGV
+populates
+.IR si_lower
+and
+.IR si_upper .
 .IP *
 .BR SIGIO / SIGPOLL
 (the two names are synonyms on Linux)
@@ -621,6 +634,10 @@ Address not mapped to object.
 .TP
 .B SEGV_ACCERR
 Invalid permissions for mapped object.
+.TP
+.BR SEGV_BNDERR " (since Linux 3.19)"
+.\" commit ee1b58d36aa1b5a79eaba11f5c3633c88231da83
+Failed address bound checks.
 .RE
 .PP
 The following values can be placed in