Due to the partial-only changes of commit 46c07316f906 ("kern: adopt the
cr_gid macro for cr_groups[0] more widely"), subsequent commit
be1f7435ef218b1d ("kern: start tracking cr_gid outside of cr_groups[]")
caused a mismatch between filling cr_groups[0] in 'reused_creds' in
fuse_interrupt_send() and reading 'cr_gid' from it in
fuse_setup_ihead(), with the consequence that the kernel would send
a FUSE_INTERRUPT message to the FUSE deamon with an uninitialized GID in
its header (which, besides being wrong, would disclose 4 bytes from its
stack).
Fixes: be1f7435ef218b1d ("kern: start tracking cr_gid outside of cr_groups[]")
Sponsored by: The FreeBSD Foundation