== patched module build (tail)
cc ... -Werror ... -c hammer_flusher.c
cc -Wl,--build-id=sha1 -nostdlib -Wl,--hash-style=sysv -r -Wl,-d -o hammer.ko ... hammer_flusher.o ...

== fixed hammer_flusher_wait codegen
000000000002b510 <hammer_flusher_wait>:
   2b510:	39 b7 7c 01 00 00    	cmp    %esi,0x17c(%rdi)
   2b516:	74 49                	je     2b561 <hammer_flusher_wait+0x51>
   2b518:	55                   	push   %rbp
   2b519:	48 89 e5             	mov    %rsp,%rbp
   2b51c:	41 56                	push   %r14
   2b51e:	4c 8d b7 7c 01 00 00 	lea    0x17c(%rdi),%r14
   2b525:	41 55                	push   %r13
   2b527:	49 c7 c5 00 00 00 00 	mov    $0x0,%r13
   2b52e:	41 54                	push   %r12