[PATCH] get rid of leak in compat_execve()

Even though copy_compat_strings() doesn't cache the pages,
copy_strings_kernel() and stuff indirectly called by e.g.
->load_binary() is doing that, so we need to drop the
cache contents in the end.

[found by WANG Cong <wangcong@zeuux.org>]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

include/linux/binfmts.h

@@ -99,6 +99,7 @@ extern int copy_strings_kernel(int argc,char ** argv,struct linux_binprm *bprm);
 extern void compute_creds(struct linux_binprm *binprm);
 extern int do_coredump(long signr, int exit_code, struct pt_regs * regs);
 extern int set_binfmt(struct linux_binfmt *new);
+extern void free_bprm(struct linux_binprm *);
 
 #endif /* __KERNEL__ */
 #endif /* _LINUX_BINFMTS_H */