| From arnd@arndb.de Fri Jul 27 11:18:04 2018 |
| From: Arnd Bergmann <arnd@arndb.de> |
| Date: Thu, 26 Jul 2018 10:13:22 +0200 |
| Subject: turn off -Wattribute-alias |
| To: stable@vger.kernel.org |
| Cc: gregkh@linuxfoundation.org, Arnd Bergmann <arnd@arndb.de>, Michal Marek <mmarek@suse.com>, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org |
| Message-ID: <20180726081358.3829157-1-arnd@arndb.de> |
| |
| From: Arnd Bergmann <arnd@arndb.de> |
| |
| 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 bee20031772a ("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: Arnd Bergmann <arnd@arndb.de> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| Makefile | 1 + |
| 1 file changed, 1 insertion(+) |
| |
| --- a/Makefile |
| +++ b/Makefile |
| @@ -642,6 +642,7 @@ KBUILD_CFLAGS += $(call cc-disable-warni |
| KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation) |
| KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow) |
| KBUILD_CFLAGS += $(call cc-disable-warning, int-in-bool-context) |
| +KBUILD_CFLAGS += $(call cc-disable-warning, attribute-alias) |
| |
| ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE |
| KBUILD_CFLAGS += $(call cc-option,-Oz,-Os) |
