[root@f26h tools]# ./btrfsslower 
In file included from /virtual/main.c:3:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/include/linux/fs.h:5:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/include/linux/wait.h:8:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/include/linux/spinlock.h:50:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/include/linux/preempt.h:80:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/preempt.h:6:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/include/linux/thread_info.h:25:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/thread_info.h:52:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/cpufeature.h:4:
/lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/processor.h:534:30: warning: taking address of packed member 'sp0' of class or structure 'x86_hw_tss' may
      result in an unaligned pointer value [-Waddress-of-packed-member]
        return this_cpu_read_stable(cpu_tss.x86_tss.sp0);
                                    ^~~~~~~~~~~~~~~~~~~
/lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/percpu.h:391:59: note: expanded from macro 'this_cpu_read_stable'
#define this_cpu_read_stable(var)       percpu_stable_op("mov", var)
                                                                ^~~
/lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/percpu.h:218:16: note: expanded from macro 'percpu_stable_op'
                    : "p" (&(var)));                    \
                             ^~~
In file included from /virtual/main.c:3:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/include/linux/fs.h:5:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/include/linux/wait.h:8:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/include/linux/spinlock.h:50:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/include/linux/preempt.h:80:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/preempt.h:6:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/include/linux/thread_info.h:25:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/thread_info.h:52:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/cpufeature.h:4:
/lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/processor.h:534:30: warning: taking address of packed member 'sp0' of class or structure 'x86_hw_tss' may
      result in an unaligned pointer value [-Waddress-of-packed-member]
        return this_cpu_read_stable(cpu_tss.x86_tss.sp0);
                                    ^~~~~~~~~~~~~~~~~~~
/lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/percpu.h:391:59: note: expanded from macro 'this_cpu_read_stable'
#define this_cpu_read_stable(var)       percpu_stable_op("mov", var)
                                                                ^~~
/lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/percpu.h:223:16: note: expanded from macro 'percpu_stable_op'
                    : "p" (&(var)));                    \
                             ^~~
In file included from /virtual/main.c:3:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/include/linux/fs.h:5:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/include/linux/wait.h:8:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/include/linux/spinlock.h:50:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/include/linux/preempt.h:80:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/preempt.h:6:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/include/linux/thread_info.h:25:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/thread_info.h:52:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/cpufeature.h:4:
/lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/processor.h:534:30: warning: taking address of packed member 'sp0' of class or structure 'x86_hw_tss' may
      result in an unaligned pointer value [-Waddress-of-packed-member]
        return this_cpu_read_stable(cpu_tss.x86_tss.sp0);
                                    ^~~~~~~~~~~~~~~~~~~
/lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/percpu.h:391:59: note: expanded from macro 'this_cpu_read_stable'
#define this_cpu_read_stable(var)       percpu_stable_op("mov", var)
                                                                ^~~
/lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/percpu.h:228:16: note: expanded from macro 'percpu_stable_op'
                    : "p" (&(var)));                    \
                             ^~~
In file included from /virtual/main.c:3:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/include/linux/fs.h:5:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/include/linux/wait.h:8:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/include/linux/spinlock.h:50:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/include/linux/preempt.h:80:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/preempt.h:6:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/include/linux/thread_info.h:25:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/thread_info.h:52:
In file included from /lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/cpufeature.h:4:
/lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/processor.h:534:30: warning: taking address of packed member 'sp0' of class or structure 'x86_hw_tss' may
      result in an unaligned pointer value [-Waddress-of-packed-member]
        return this_cpu_read_stable(cpu_tss.x86_tss.sp0);
                                    ^~~~~~~~~~~~~~~~~~~
/lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/percpu.h:391:59: note: expanded from macro 'this_cpu_read_stable'
#define this_cpu_read_stable(var)       percpu_stable_op("mov", var)
                                                                ^~~
/lib/modules/4.11.3-300.fc26.x86_64/build/arch/x86/include/asm/percpu.h:233:16: note: expanded from macro 'percpu_stable_op'
                    : "p" (&(var)));                    \
                             ^~~
4 warnings generated.
Segmentation fault (core dumped)