Re: RFC: remove set_fs for m68k

Christoph Hellwig
2021-07-13T08:54:22Z

On Tue, Jul 13, 2021 at 08:16:25PM +1200, Michael Schmitz wrote:
> I'll try that next. It certainly ran fine when I tried your earlier version
> which still had the __constant_copy_from_user() (but modified to use
> __get_user_asm() for the 1, 2 and 4 byte cases). That doesn't prove much
> though - I may not have hit the exact same memory pressure (not sure how
> often savelogs runs on that system, and I haven't checked how much the
> kernel size differs between the two versions).
>
> Anyway, I'll try my previous version again, and I'll try with the WARN_ON
> removed, but that'll take a few days (did I mention this 030 is clocked at
> 16 MHz only?).

No problem.

> I suspect it may get called from an interrupt - not sure what interrupt
> handler would call vm_map_ram(), or if that even is allowed though. Might
> happen during a softirq, which is covered by in_interrupt as well ...

vm_map_ram isn't allowed to be called from interrupts, just like all the
vmalloc/vmap code. But that doesn't mean it might not have crept in
somewhere.