kmemleak and SLAB

Hi,

When I try to use kmemleak with the SLAB allocator set I receive this message when booting 3.1-rc8:

[   28.480569] kmemleak: Cannot allocate a kmemleak_object structure
[   28.480593] kmemleak: Kernel memory leak detector disabled
[   34.428037] CPA self-test:
[   34.435881]  4k 259968 large 0 gb 0 x 259968[b0000000-ef77f000] miss 0
[   34.447669]  4k 259968 large 0 gb 0 x 259968[b0000000-ef77f000] miss 0
[   34.458402]  4k 259968 large 0 gb 0 x 259968[b0000000-ef77f000] miss 0
[   34.458407] ok.
[   38.754032] wlan0: no IPv6 routers present
[   67.666048] kmemleak: Automatic memory scanning thread ended

All is fine when using SLUB. On another run I also got an error about an ODEBUG oom so I wonder if this is indicative of another problem...

Sitsofe | http://sucs.org/~sits/

There could be another problem. The kmemleak error says that it could not allocate the memory required for its internal data keeping. This happens especially when the allocation is GFP_ATOMIC (it depends on the context kmemleak is called from).

I have this commit in my tree (not yet pushed upstream):

http://linux-arm.org/git?p=linux-2.6.git;a=commitdiff;h=bcba31f1751bf9d9d1da72dd828dee697d52924f

If you apply this, kmemleak keeps its metadata for later reporting (well, only if it was fully initialised before the error occured). This way you can inspect /proc/slabinfo and /proc/meminfo etc. to see why it ran out of memory.

Catalin