[RFAv2,3/3] Document 'set|show exec-file-mismatch (ask|warn|off)'

diff --git a/gdb/NEWS b/gdb/NEWS
index 1305eceeca..d4e2e70f38 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -10,6 +10,19 @@ 
   that support it (see entry for GDB 9, below), providing faster
   performance for programs with many symbols.
 
+* New commands
+
+set exec-file-mismatch -- Set exec-file-mismatch handling (ask|warn|off).
+show exec-file-mismatch -- Show exec-file-mismatch handling (ask|warn|off).
+  Set or show the option 'exec-file-mismatch'.  When GDB attaches to
+  a running process and can determine the name of the executable file
+  the process runs, this new option indicates whether to detect mismatch
+  between the name of the current executable file loaded by GDB
+  and the name of the executable file used to start the process.
+  If 'ask', the default, display a warning and ask the user
+  whether to load the process executable file; if 'warn', just display
+  a warning; if 'off', don't attempt to detect a mismatch.
+
 *** Changes in GDB 9
 
 * 'thread-exited' event is now available in the annotations interface.
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 67882d0cd8..2a38b03f33 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -2905,6 +2905,30 @@  the program is not found) by using the source file search path
 the @code{file} command to load the program.  @xref{Files, ,Commands to
 Specify Files}.
 
+@anchor{set exec-file-mismatch}
+If the debugger can determine the name of the executable file running
+in the process it is attaching to, and this file name does not match
+the name of the current exec-file loaded by @value{GDBN}, the option
+@code{exec-file-mismatch} specifies how to handle the mismatch.
+
+@table @code
+@kindex exec-file-mismatch
+@cindex set exec-file-mismatch
+@item set exec-file-mismatch @samp{ask|warn|off}
+
+Whether to detect mismatch between the name of the current executable
+file loaded by @value{GDBN} and the name of the executable file used to
+start the process.  If @samp{ask}, the default, display a warning
+and ask the user whether to load the process executable file; if
+@samp{warn}, just display a warning; if @samp{off}, don't attempt to
+detect a mismatch.
+
+@cindex show exec-file-mismatch
+@item show exec-file-mismatch
+Show the current value of @code{exec-file-mismatch}.
+
+@end table
+
 The first thing @value{GDBN} does after arranging to debug the specified
 process is to stop it.  You can examine and modify an attached process
 with all the @value{GDBN} commands that are ordinarily available when
@@ -21839,6 +21863,12 @@  established.  If you are using @code{gdbserver}, you may also invoke
 @code{gdbserver} using the @option{--attach} option
 (@pxref{Running gdbserver}).
 
+Some remote targets allow @value{GDBN} to determine the executable file running
+in the process the debugger is attaching to.  In such a case, @value{GDBN}
+uses the value of @code{exec-file-mismatch} to handle a possible mismatch
+between the executable file name running in the process and the name of the
+current exec-file loaded by @value{GDBN} (@pxref{set exec-file-mismatch}).
+
 @end table
 
 @anchor{Host and target files}