From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Shevchenko Subject: Re: linux-next: build failure after merge of the aio tree Date: Tue, 15 Mar 2016 16:38:51 +0200 Message-ID: References: <20160315174634.6766cd88@canb.auug.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Received: from mail-ob0-f173.google.com ([209.85.214.173]:33037 "EHLO mail-ob0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932470AbcCOOiw (ORCPT ); Tue, 15 Mar 2016 10:38:52 -0400 In-Reply-To: <20160315174634.6766cd88@canb.auug.org.au> Sender: linux-next-owner@vger.kernel.org List-ID: To: Stephen Rothwell Cc: Benjamin LaHaise , linux-next , "linux-kernel@vger.kernel.org" , Michael Ellerman , Benjamin Herrenschmidt , linuxppc-dev@lists.ozlabs.org, Al Viro , Christoph Hellwig On Tue, Mar 15, 2016 at 8:46 AM, Stephen Rothwell wrote: > 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' avr32 seems affected as well and the below solution is not suitable (should be much more verbose in asm, I guess). > > 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 -- With Best Regards, Andy Shevchenko