On Fri, 23 Oct 2020 at 08:35, Linus Torvalds torvalds@linux-foundation.org wrote:
On Thu, Oct 22, 2020 at 6:36 PM Daniel Díaz daniel.diaz@linaro.org wrote:
The kernel Naresh originally referred to is here: https://builds.tuxbuild.com/SCI7Xyjb7V2NbfQ2lbKBZw/
is unnecessary (because the 8-byte case is still just a single register, no %eax:%edx games needed), it would be interesting to hear if the attached patch fixes it. That would confirm that the problem really is due to some register allocation issue interaction (or, alternatively, it would tell me that there's something else going on).
[Old patch from yesterday]
After applying your patch on top on linux next tag 20201015 there are two observations, 1) i386 build failed. please find build error build 2) x86_64 kasan test PASS and the reported error not found.
i386 build failure, ---------------------- make -sk KBUILD_BUILD_USER=TuxBuild -C/linux -j16 ARCH=i386 HOSTCC=gcc CC="sccache gcc" O=build # In file included from ../include/linux/uaccess.h:11, from ../arch/x86/include/asm/fpu/xstate.h:5, from ../arch/x86/include/asm/pgtable.h:26, from ../include/linux/pgtable.h:6, from ../include/linux/mm.h:33, from ../include/linux/memblock.h:13, from ../fs/proc/page.c:2: ../fs/proc/page.c: In function ‘kpagecgroup_read’: ../arch/x86/include/asm/uaccess.h:217:2: error: inconsistent operand constraints in an ‘asm’ 217 | asm volatile("call __" #fn "_%P[size]" \ | ^~~ ../arch/x86/include/asm/uaccess.h:244:44: note: in expansion of macro ‘do_put_user_call’ 244 | #define put_user(x, ptr) ({ might_fault(); do_put_user_call(put_user,x,ptr); }) | ^~~~~~~~~~~~~~~~ ../fs/proc/page.c:307:7: note: in expansion of macro ‘put_user’ 307 | if (put_user(ino, out)) { | ^~~~~~~~ make[3]: *** [../scripts/Makefile.build:283: fs/proc/page.o] Error 1 make[3]: Target '__build' not remade because of errors. make[2]: *** [../scripts/Makefile.build:500: fs/proc] Error 2 In file included from ../include/linux/uaccess.h:11, from ../include/linux/sched/task.h:11, from ../include/linux/sched/signal.h:9, from ../include/linux/rcuwait.h:6, from ../include/linux/percpu-rwsem.h:7, from ../include/linux/fs.h:33, from ../include/linux/cgroup.h:17, from ../include/linux/memcontrol.h:13, from ../include/linux/swap.h:9, from ../include/linux/suspend.h:5, from ../kernel/power/user.c:10: ../kernel/power/user.c: In function ‘snapshot_ioctl’: ../arch/x86/include/asm/uaccess.h:217:2: error: inconsistent operand constraints in an ‘asm’ 217 | asm volatile("call __" #fn "_%P[size]" \ | ^~~ ../arch/x86/include/asm/uaccess.h:244:44: note: in expansion of macro ‘do_put_user_call’ 244 | #define put_user(x, ptr) ({ might_fault(); do_put_user_call(put_user,x,ptr); }) | ^~~~~~~~~~~~~~~~ ../kernel/power/user.c:340:11: note: in expansion of macro ‘put_user’ 340 | error = put_user(size, (loff_t __user *)arg); | ^~~~~~~~ ../arch/x86/include/asm/uaccess.h:217:2: error: inconsistent operand constraints in an ‘asm’ 217 | asm volatile("call __" #fn "_%P[size]" \ | ^~~ ../arch/x86/include/asm/uaccess.h:244:44: note: in expansion of macro ‘do_put_user_call’ 244 | #define put_user(x, ptr) ({ might_fault(); do_put_user_call(put_user,x,ptr); }) | ^~~~~~~~~~~~~~~~ ../kernel/power/user.c:346:11: note: in expansion of macro ‘put_user’ 346 | error = put_user(size, (loff_t __user *)arg); | ^~~~~~~~ ../arch/x86/include/asm/uaccess.h:217:2: error: inconsistent operand constraints in an ‘asm’ 217 | asm volatile("call __" #fn "_%P[size]" \ | ^~~ ../arch/x86/include/asm/uaccess.h:244:44: note: in expansion of macro ‘do_put_user_call’ 244 | #define put_user(x, ptr) ({ might_fault(); do_put_user_call(put_user,x,ptr); }) | ^~~~~~~~~~~~~~~~ ../kernel/power/user.c:357:12: note: in expansion of macro ‘put_user’ 357 | error = put_user(offset, (loff_t __user *)arg); | ^~~~~~~~
x86_64 Kasan tested and the reported issue not found. https://lkft.validation.linaro.org/scheduler/job/1868029#L2374
- Naresh