[RFC 1/2] mm, slub: prevent kmalloc_node crashes and memory leaks

[Sachin Sant]

> OK how about this version? It's somewhat ugly, but important is that the fast
> path case (c->page exists) is unaffected and another common case (c->page is
> NULL, but node is NUMA_NO_NODE) is just one extra check - impossible to avoid at
> some point anyway.
> 

I attempted the suggested tests.

Test 1: March 18 linux-next + Patch 1 [1] + Patch  2 [2]

Machine boots fine. numactl o/p after boot:

# numactl -H
available: 2 nodes (0-1)
node 0 cpus:
node 0 size: 0 MB
node 0 free: 0 MB
node 1 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
node 1 size: 35631 MB
node 1 free: 32724 MB
node distances:
node   0   1
  0:  10  40
  1:  40  10
#

Test 2: Code base as used in Test 1 + 3 patch series from Srikar [3]

Machine boots fine. numactl o/p after boot:

# numactl -H
available: 1 nodes (1)
node 1 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
node 1 size: 35631 MB
node 1 free: 32711 MB
node distances:
node   1
  1:  10
#

Thanks!
-Sachin


[1] https://lore.kernel.org/linux-mm/e060ad43-ff4e-0e59-2e64-ce8a4916ec70@suse.cz/T/#mb8d0a358dc5c5fb9661fa45047072a92c510faf2
[2] https://lore.kernel.org/linux-mm/e060ad43-ff4e-0e59-2e64-ce8a4916ec70@suse.cz/T/#mce342e54a95ce2ee3043901e52d70ee2fd94c516
[3] https://lore.kernel.org/linux-mm/20200311110237.5731-1-srikar@linux.vnet.ibm.com/