So a GCC 9 escaped to Fedora Rawhide in the last few days, and things didn't go well. Fortunately, I had the 8.2.1-7 RPMs still around.
Issue 1: There's a new warning added for taking the address of a member of a packed array. It wasn't *too* noisy. Issue 2: Looks like it's not ready for prime time. CC [M] fs/ntfs/super.o fs/ntfs/super.c: In function 'is_boot_sector_ntfs': fs/ntfs/super.c:597:3: warning: converting a packed 'const NTFS_BOOT_SECTOR *' {aka 'const struct <anonymous> *'} pointer (alignment 1) to 'le32' {aka 'unsigned int'} (alignment 4) may result in an unaligned pointer value [-Waddress-of-packed-member] 597 | for (i = 0, u = (le32*)b; u < (le32*)(&b->checksum); ++u) | ^~~ fs/ntfs/super.c:597:3: internal compiler error: Segmentation fault Please submit a full bug report, with preprocessed source if appropriate. See <http://bugzilla.redhat.com/bugzilla> for instructions. Preprocessed source stored into /tmp/cc0KDLoH.out file, please attach this to your bugreport. make[2]: *** [scripts/Makefile.build:277: fs/ntfs/super.o] Error 1 make[1]: *** [scripts/Makefile.build:491: fs/ntfs] Error 2 make: *** [Makefile:1044: fs] Error 2 I've reported this to the RedHat/Fedora crew as: https://bugzilla.redhat.com/show_bug.cgi?id=1669696