diff --git a/gdb/cli/cli-cmds.c b/gdb/cli/cli-cmds.c
index 2ec2dd3..1d57c94 100644
--- a/gdb/cli/cli-cmds.c
+++ b/gdb/cli/cli-cmds.c
@@ -754,6 +754,12 @@ shell_escape (char *arg, int from_tty)
 
       if ((user_shell = (char *) getenv ("SHELL")) == NULL)
 	user_shell = "/bin/sh";
+      else
+	{
+	  if (!valid_shell (user_shell))
+	    warning (_("The specified shell '%s' is not valid.  The command "
+		       "will not be executed."), user_shell);
+	}
 
       /* Get the name of the shell for arg0.  */
       p = lbasename (user_shell);
diff --git a/gdb/fork-child.c b/gdb/fork-child.c
index 4ba62b0..36618a4 100644
--- a/gdb/fork-child.c
+++ b/gdb/fork-child.c
@@ -108,6 +108,58 @@ escape_bang_in_quoted_argument (const char *shell_file)
   return 0;
 }
 
+/* Check if the user has specified any shell to start the inferior,
+   and if the specified shell is valid (i.e., it exists and can be
+   executed by the user).
+
+   The shell specified by the user, if any, is SHELL_FILE_ARG.
+
+   DEFAULT_SHELL_FILE is the default shell that will be used by GDB if
+   the user said she wants to start the inferior using a shell (i.e.,
+   STARTUP_WITH_SHELL is 1) but no shell has been specified by the
+   user (i.e., the $SHELL environment variable is NULL).
+
+   If the specified shell is invalid (see utils.h:valid_shell for
+   details), this function will print a warning to the user, but *will
+   still return 1*.
+
+   Return 1 if the STARTUP_WITH_SHELL is set (even if the specified
+   shell is invalid); zero otherwise.  */
+
+static int
+check_startup_with_shell (char **shell_file, char *shell_file_arg,
+			  char *default_shell_file)
+{
+  /* 'startup_with_shell' is declared in inferior.h and bound to the
+     "set startup-with-shell" option.  If 0, we'll just do a
+     fork/exec, no shell, so don't bother figuring out what shell.  */
+  if (startup_with_shell)
+    {
+      gdb_assert (shell_file != NULL);
+      gdb_assert (default_shell_file != NULL);
+      *shell_file = shell_file_arg;
+
+      /* Figure out what shell to start up the user program under.  */
+      if (*shell_file == NULL)
+	*shell_file = getenv ("SHELL");
+      if (*shell_file == NULL)
+	{
+	  /* No shell was specified, so we just stick to the default
+	     behavior which is to use DEFAULT_SHELL_FILE.  */
+	  *shell_file = default_shell_file;
+	}
+      else if (!valid_shell (*shell_file))
+	warning (_("The specified shell '%s' is not valid.  You will see\n"
+		   "an error when trying to execute the inferior."),
+		 *shell_file);
+
+      /* We return 1 here even though the shell might be invalid.  */
+      return 1;
+    }
+
+  return 0;
+}
+
 /* Start an inferior Unix child process and sets inferior_ptid to its
    pid.  EXEC_FILE is the file to run.  ALLARGS is a string containing
    the arguments to the program.  ENV is the environment vector to
@@ -148,19 +200,8 @@ fork_inferior (char *exec_file_arg, char *allargs, char **env,
   if (exec_file == 0)
     exec_file = get_exec_file (1);
 
-  /* 'startup_with_shell' is declared in inferior.h and bound to the
-     "set startup-with-shell" option.  If 0, we'll just do a
-     fork/exec, no shell, so don't bother figuring out what shell.  */
-  shell_file = shell_file_arg;
-  if (startup_with_shell)
-    {
-      /* Figure out what shell to start up the user program under.  */
-      if (shell_file == NULL)
-	shell_file = getenv ("SHELL");
-      if (shell_file == NULL)
-	shell_file = default_shell_file;
-      shell = 1;
-    }
+  shell = check_startup_with_shell (&shell_file, shell_file_arg,
+				    default_shell_file);
 
   if (!shell)
     {
diff --git a/gdb/testsuite/gdb.base/invalid-shell.exp b/gdb/testsuite/gdb.base/invalid-shell.exp
new file mode 100644
index 0000000..0542a53
--- /dev/null
+++ b/gdb/testsuite/gdb.base/invalid-shell.exp
@@ -0,0 +1,48 @@
+# Copyright 2015 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+standard_testfile normal.c
+
+if { [is_remote target] || ![isnative] } {
+    untested "cannot test on remote targets"
+    return -1
+}
+
+if { [istarget "*-*-mingw*"] || [istarget "*-*-cygwin*"] } {
+    untested "cannot test on mingw or cygwin"
+    return -1
+}
+
+if { [prepare_for_testing "failed to prepare" $testfile $srcfile debug] } {
+    untested "could not compile test program"
+    return -1
+}
+
+gdb_exit
+
+# Set the $SHELL to an invalid file.  This will cause GDB to use
+# /bin/sh instead.
+set oldshell $env(SHELL)
+set env(SHELL) "/invalid/path/to/file"
+
+clean_restart $binfile
+
+# Running the inferior must work.
+gdb_test "run" "Starting program: .*\r\nwarning: The specified shell \\\'/invalid/path/to/file\\\' is not valid.  You will see\r\nan error when trying to execute the inferior.\r\nCannot exec /invalid/path/to/file -c exec .*$testfile .\r\nError: No such file or directory\r\nDuring startup program exited with code $decimal." "starting with /bin/sh instead of invalid shell"
+
+# Invoking a shell command must also work.
+gdb_test "shell echo hi" "warning: The specified shell \\\'/invalid/path/to/file\\\' is not valid.  The command will not be executed.\r\nCannot execute /invalid/path/to/file: No such file or directory" "invoking shell command from prompt"
+
+set env(SHELL) $oldshell
diff --git a/gdb/utils.c b/gdb/utils.c
index acb4c7d..bf970fd 100644
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -25,6 +25,7 @@
 #include "gdbthread.h"
 #include "fnmatch.h"
 #include "gdb_bfd.h"
+#include "filestuff.h"
 #ifdef HAVE_SYS_RESOURCE_H
 #include <sys/resource.h>
 #endif /* HAVE_SYS_RESOURCE_H */
@@ -3364,6 +3365,58 @@ gdb_filename_fnmatch (const char *pattern, const char *string, int flags)
   return fnmatch (pattern, string, flags);
 }
 
+/* See utils.h.  */
+
+int
+valid_shell (const char *shell)
+{
+  pid_t shell_pid;
+  int status;
+  size_t len = strlen (shell);
+  char *shell_argv[4];
+
+  if (shell == NULL || access (shell, X_OK) != 0)
+    return 0;
+
+  shell_argv[0] = alloca (len + 1);
+  strncpy (shell_argv[0], shell, len);
+  shell_argv[0][len] = '\0';
+  shell_argv[1] = "-c";
+  shell_argv[2] = "exit 42";
+  shell_argv[3] = (char *) NULL;
+  shell_pid = fork ();
+
+  switch (shell_pid)
+    {
+    case -1:
+      /* vfork failed.  Let's just return 0 because we could not
+	 figure out if the shell is valid or not.  */
+      return 0;
+
+    case 0:
+      /* Closing everything as we will not need (and don't want) to
+	 output any message.  */
+      close_most_fds ();
+      close (STDOUT_FILENO);
+      close (STDERR_FILENO);
+      close (STDIN_FILENO);
+      execvp (shell_argv[0], shell_argv);
+      /* If we get here, it's an error.  Just return an invalid
+	 thing.  */
+      _exit (0177);
+
+    default:
+      waitpid (shell_pid, &status, 0);
+      if (WIFEXITED (status))
+	return WEXITSTATUS (status) == 42;
+      else
+	{
+	  kill (SIGKILL, shell_pid);
+	  return 0;
+	}
+    }
+}
+
 /* Provide a prototype to silence -Wmissing-prototypes.  */
 extern initialize_file_ftype _initialize_utils;
 
diff --git a/gdb/utils.h b/gdb/utils.h
index 995a1cf..cc19711 100644
--- a/gdb/utils.h
+++ b/gdb/utils.h
@@ -369,4 +369,20 @@ extern void dump_core (void);
 
 extern char *make_hex_string (const gdb_byte *data, size_t length);
 
+/* Return 1 if SHELL is a valid shell to execute a command, zero
+   otherwise.
+
+   In oder to perform the check for a valid shell, this function will
+   fork GDB, and then execute a simple command: $SHELL -c 'exit 42'.
+   This command shall make the SHELL return 42; if this number is not
+   returned, it (probably) means that SHELL is not valid.  We say
+   'probably' because it is trivial to create a program that just
+   returns 42 and ignores its arguments; in this case, this function
+   would consider it as a valid shell even though it is clearly not.
+   But even in this case GDB would later fail to execute anything, so
+   that only means that the user would not get a nice warning message
+   in this case.  */
+
+extern int valid_shell (const char *shell);
+
 #endif /* UTILS_H */
