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  • Arnd Bergmann's avatar
    turn off -Wattribute-alias · e94f784f
    Arnd Bergmann authored
    Starting with gcc-8.1, we get a warning about all system call definitions,
    which use an alias between functions with incompatible prototypes, e.g.:
    
    In file included from ../mm/process_vm_access.c:19:
    ../include/linux/syscalls.h:211:18: warning: 'sys_process_vm_readv' alias between functions of incompatible types 'long int(pid_t,  const struct iovec *, long unsigned int,  const struct iovec *, long unsigned int,  long unsigned int)' {aka 'long int(int,  const struct iovec *, long unsigned int,  const struct iovec *, long unsigned int,  long unsigned int)'} and 'long int(long int,  long int,  long int,  long int,  long int,  long int)' [-Wattribute-alias]
      asmlinkage long sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \
                      ^~~
    ../include/linux/syscalls.h:207:2: note: in expansion of macro '__SYSCALL_DEFINEx'
      __SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
      ^~~~~~~~~~~~~~~~~
    ../include/linux/syscalls.h:201:36: note: in expansion of macro 'SYSCALL_DEFINEx'
     #define SYSCALL_DEFINE6(name, ...) SYSCALL_DEFINEx(6, _##name, __VA_ARGS__)
                                        ^~~~~~~~~~~~~~~
    ../mm/process_vm_access.c:300:1: note: in expansion of macro 'SYSCALL_DEFINE6'
     SYSCALL_DEFINE6(process_vm_readv, pid_t, pid, const struct iovec __user *, lvec,
     ^~~~~~~~~~~~~~~
    ../include/linux/syscalls.h:215:18: note: aliased declaration here
      asmlinkage long SyS##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
                      ^~~
    ../include/linux/syscalls.h:207:2: note: in expansion of macro '__SYSCALL_DEFINEx'
      __SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
      ^~~~~~~~~~~~~~~~~
    ../include/linux/syscalls.h:201:36: note: in expansion of macro 'SYSCALL_DEFINEx'
     #define SYSCALL_DEFINE6(name, ...) SYSCALL_DEFINEx(6, _##name, __VA_ARGS__)
                                        ^~~~~~~~~~~~~~~
    ../mm/process_vm_access.c:300:1: note: in expansion of macro 'SYSCALL_DEFINE6'
     SYSCALL_DEFINE6(process_vm_readv, pid_t, pid, const struct iovec __user *, lvec,
    
    This is really noisy and does not indicate a real problem. In the latest
    mainline kernel, this was addressed by commit bee20031
    
     ("disable
    -Wattribute-alias warning for SYSCALL_DEFINEx()"), which seems too invasive
    to backport.
    
    This takes a much simpler approach and just disables the warning across the
    kernel.
    
    Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    e94f784f