Re: Total system lockup with Alt-SysRQ-L

[Alan Cox]

> option, would be a one-button "sync up all the disks, forbid any more
> writes, save as much state as possbile (registers, memory) to a swap
> partition, set a flag for crash dump processing and reboot" capability.

Very hard to do - you can't trust the I/O systems state so the dump code
has to verify it hasnt been corrupted, reconfigure the drive it wishes to
write to, write the data out using its own non interrupt driven code and
then halt the box.

There are folks with patches that do a lot of that (lkcd)