From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Rothwell Subject: linux-next: build failure after merge of the aio tree Date: Tue, 15 Mar 2016 17:46:34 +1100 Message-ID: <20160315174634.6766cd88@canb.auug.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from ozlabs.org ([103.22.144.67]:43881 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754886AbcCOGqu (ORCPT ); Tue, 15 Mar 2016 02:46:50 -0400 Sender: linux-next-owner@vger.kernel.org List-ID: To: Benjamin LaHaise Cc: linux-next@vger.kernel.org, linux-kernel@vger.kernel.org, Michael Ellerman , Benjamin Herrenschmidt , linuxppc-dev@lists.ozlabs.org, Al Viro , Christoph Hellwig Hi Benjamin, After merging the aio tree, today's linux-next build (powerpc ppc44x_defconfig) failed like this: fs/built-in.o: In function `aio_thread_op_foo_at': aio.c:(.text+0x4dab4): undefined reference to `__get_user_bad' aio.c:(.text+0x4daec): undefined reference to `__get_user_bad' Caused by commit 150a0b4905f1 ("aio: add support for async openat()") despite commit d2f7a973e11e ("aio: don't use __get_user() for 64 bit values") This is due to a bug in the powerpc __get_user_check() macro (the return value is defined to be "unsigned long" which is only 32 bits on a 32 bit platform). I applied the patch below which seems to help (Michael, what do you think?), but given Al's and Christoph's reactions, I am inclined to remove the aio tree from tomorrow and maybe it can be revisited after the merge window. From: Stephen Rothwell Date: Tue, 15 Mar 2016 16:36:06 +1100 Subject: [PATCH] powerpc: fix get_user for 64 bit typs on 32 bit platforms solution borrowed from the x86 uaccess.h Signed-off-by: Stephen Rothwell --- arch/powerpc/include/asm/uaccess.h | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h index b7c20f0b8fbe..52262b2f37fc 100644 --- a/arch/powerpc/include/asm/uaccess.h +++ b/arch/powerpc/include/asm/uaccess.h @@ -261,10 +261,13 @@ do { \ } \ } while (0) +#define __inttype(x) \ + __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL)) + #define __get_user_nocheck(x, ptr, size) \ ({ \ long __gu_err; \ - unsigned long __gu_val; \ + __inttype(*(ptr)) __gu_val; \ __typeof__(*(ptr)) __user *__gu_addr = (ptr); \ __chk_user_ptr(ptr); \ if (!is_kernel_addr((unsigned long)__gu_addr)) \ @@ -277,7 +280,7 @@ do { \ #define __get_user_check(x, ptr, size) \ ({ \ long __gu_err = -EFAULT; \ - unsigned long __gu_val = 0; \ + __inttype(*(ptr)) __gu_val = 0; \ __typeof__(*(ptr)) __user *__gu_addr = (ptr); \ might_fault(); \ if (access_ok(VERIFY_READ, __gu_addr, (size))) \ @@ -289,7 +292,7 @@ do { \ #define __get_user_nosleep(x, ptr, size) \ ({ \ long __gu_err; \ - unsigned long __gu_val; \ + __inttype(*(ptr)) __gu_val; \ __typeof__(*(ptr)) __user *__gu_addr = (ptr); \ __chk_user_ptr(ptr); \ __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \ -- 2.7.0 -- Cheers, Stephen Rothwell