Unexpected error while compiling Linux kernel 4.4.0

Question

During compilation of linux kernel 4.4.0 appears an error:

fs/overlayfs/super.c: In function ‘ovl_init’:
fs/overlayfs/super.c:1331:30: error: ‘ovl_v1_fs_type’ undeclared (first use in this function)
ret = register_filesystem(&ovl_v1_fs_type);
                          ^
fs/overlayfs/super.c:1331:30: note: each undeclared identifier is reported only once for each function it appears in
fs/overlayfs/super.c: In function ‘ovl_exit’:
fs/overlayfs/super.c:1344:26: error: ‘ovl_v1_fs_type’ undeclared (first use in this function)
unregister_filesystem(&ovl_v1_fs_type);
                      ^
scripts/Makefile.build:277: recipe for target 'fs/overlayfs/super.o' failed
make[4]: *** [fs/overlayfs/super.o] Error 1
scripts/Makefile.build:484: recipe for target 'fs/overlayfs' failed
make[3]: *** [fs/overlayfs] Error 2
Makefile:996: recipe for target 'fs' failed
make[2]: *** [fs] Error 2
scripts/package/Makefile:90: recipe for target 'deb-pkg' failed
make[1]: *** [deb-pkg] Error 2
Makefile:1286: recipe for target 'deb-pkg' failed
make: *** [deb-pkg] Error 2

Additional information:

Processor: Intel® Core™ i3-3110M CPU @ 2.40GHz × 4 OS type: 64-bit

Graphics: GeForce GT 720M/PCIe/SSE2

uname -a
Linux Khumayun 4.15.18 #1 SMP Sat Oct 13 22:05:33 +05 2018 x86_64 x86_64 x86_64 GNU/Linux

Answer 1

Looks like a bug in the kernel modified by Ubuntu.

You may either enable CONFIG_OVERLAY_FS_V1 configuration option, or apply the patch .