| Message ID | 20160315174634.6766cd88@canb.auug.org.au (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On Tue, Mar 15, 2016 at 8:46 AM, Stephen Rothwell <sfr@canb.auug.org.au> 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 <sfr@canb.auug.org.au> > 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 <sfr@canb.auug.org.au> > --- > 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 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
On Tuesday 15 March 2016 16:38:51 Andy Shevchenko wrote: > On Tue, Mar 15, 2016 at 8:46 AM, Stephen Rothwell <sfr@canb.auug.org.au> 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 <arnd@arndb.de> 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()")
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
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); \
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 <sfr@canb.auug.org.au> 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 <sfr@canb.auug.org.au> --- arch/powerpc/include/asm/uaccess.h | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)