Writeback drain stalls Tasks-RCU, panics hosts on BPF detach
Cgroup writeback cleanup can run for minutes without a Tasks-RCU quiescent state on lazy-preempt kernels, blocking ftrace and BPF unlinks until the hung-task detector fires.
By kexec#writeback
Ext4 buffered I/O shifts from buffer_head to iomap
Zhang Yi posts v6 of a 31-patch series that modernizes regular-file buffered reads and writes while reworking EOF and journal ordering.
By kexecBtrfs folio lock leak hangs KVM guests on file-backed RAM
Large data folios dirtied via GUP without subpage bits leave writeback holding a lock forever, stalling guests and host flushers.
By kexec