20 Sep
2020
20 Sep
'20
5:58 p.m.
On Sun, Sep 20, 2020 at 10:42 AM Linus Torvalds torvalds@linux-foundation.org wrote:
Yeah, that looks much easier to explain. Ack.
Btw, one thing that might be a good idea at least initially is to add a check for p->kmap_ctrl.idx being zero at fork, exit and maybe syscall return time (but that last one may be too cumbersome to really worry about).
The kmap_atomic() interface basically has a lot of coverage for leaked as part of all the "might_sleep()" checks sprinkled around, The new kmap_temporary/local/whatever wouldn't have that kind of incidental debug checking, and any leaked kmap indexes would be rather hard to debug (much) later when they cause index overflows or whatever.
Linus