There is an NULL pointer dereference in move_data_page in fs/f2fs/gc.c when f2fs tries to migrate a block that belongs to special file, and the file doesn't have assigned address space operations pointer array for mapping->a_ops field but called a_ops->set_dirty_page(). Reference: https://bugzilla.kernel.org/show_bug.cgi?id=215231
Created kernel tracking bugs for this issue: Affects: fedora-all [bug 2054137]
This was fixed for Fedora with the 5.15.17 stable kernel updates.
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): https://access.redhat.com/security/cve/cve-2021-44879