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 <[email protected]>
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 <[email protected]>
---
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
On Tue, Mar 15, 2016 at 8:46 AM, Stephen Rothwell <[email protected]> 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 <[email protected]>
> 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 <[email protected]>
> ---
> 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
On Tue, Mar 15, 2016 at 05:46:34PM +1100, 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'
>
> 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).
m68k allmodconfig and all defs of m32r fails while building next-20160315.
regards
sudip
On Tue, Mar 15, 2016 at 04:19:02PM +0000, Sudip Mukherjee wrote:
> On Tue, Mar 15, 2016 at 05:46:34PM +1100, 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'
> >
> > 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).
>
> m68k allmodconfig and all defs of m32r fails while building next-20160315.
>
> regards
> sudip
I've removed everything from the aio-next.git tree for now. Will revisit
after the merge window.
-ben
--
"Thought is the essence of where you are now."
On Tuesday 15 March 2016 16:38:51 Andy Shevchenko wrote:
> On Tue, Mar 15, 2016 at 8:46 AM, Stephen Rothwell <[email protected]> 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).
>
ARM as well, at least for ARMv7-M.
Arnd
On Tuesday 15 March 2016 12:22:28 Benjamin LaHaise wrote:
> On Tue, Mar 15, 2016 at 04:19:02PM +0000, Sudip Mukherjee wrote:
> > On Tue, Mar 15, 2016 at 05:46:34PM +1100, 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'
> > >
> > > 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).
> >
> > m68k allmodconfig and all defs of m32r fails while building next-20160315.
> >
> > regards
> > sudip
>
> I've removed everything from the aio-next.git tree for now. Will revisit
> after the merge window.
>
I've also sent a patch that fixes the link error on ARM and that should
work on all other architectures too.
Arnd
On Wed, Mar 16, 2016 at 12:02 AM, Arnd Bergmann <[email protected]> wrote:
> On Tuesday 15 March 2016 12:22:28 Benjamin LaHaise wrote:
>> On Tue, Mar 15, 2016 at 04:19:02PM +0000, Sudip Mukherjee wrote:
>> > On Tue, Mar 15, 2016 at 05:46:34PM +1100, 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'
>> > >
>> > > Caused by commit
>> > >
>> > > 150a0b4905f1 ("aio: add support for async openat()")
>> > >
>> > > despite commit
>> > >
>> > > d2f7a973e11e ("aio: don't use __get_user() for 64 bit values")
>> > >
>> I've removed everything from the aio-next.git tree for now. Will revisit
>> after the merge window.
I think it is the best solution right now.
> I've also sent a patch that fixes the link error on ARM and that should
> work on all other architectures too.
In case of avr32 signalfd_read() fails. Does your patch help with it as well?
P.S. Bisecting shows same culprit: 150a0b4905f1 ("aio: add support for
async openat()")
--
With Best Regards,
Andy Shevchenko
On Wednesday 16 March 2016 13:12:36 Andy Shevchenko wrote:
>
> > I've also sent a patch that fixes the link error on ARM and that should
> > work on all other architectures too.
>
> In case of avr32 signalfd_read() fails. Does your patch help with it as well?
>
> P.S. Bisecting shows same culprit: 150a0b4905f1 ("aio: add support for
> async openat()")
I don't know. What is the symptom on avr32? My patch only removes the
get_user() instances on 64-bit values and replaces them with a
single copy_from_user() call.
Arnd
On Wed, Mar 16, 2016 at 02:59:38PM +0100, Arnd Bergmann wrote:
> On Wednesday 16 March 2016 13:12:36 Andy Shevchenko wrote:
> >
> > > I've also sent a patch that fixes the link error on ARM and that should
> > > work on all other architectures too.
> >
> > In case of avr32 signalfd_read() fails. Does your patch help with it as well?
> >
> > P.S. Bisecting shows same culprit: 150a0b4905f1 ("aio: add support for
> > async openat()")
>
> I don't know. What is the symptom on avr32? My patch only removes the
> get_user() instances on 64-bit values and replaces them with a
> single copy_from_user() call.
Which is the wrong fix. Arch code should be able to handle 64 bit values
in all the get/put_user() variants. We use 64 bit variables all over the
place in interfaces to userspace.
-ben