Re: BUG: Bad page map in process udevd (anon_vma: (null)) in 2.6.38-rc4

On Thu 17-02-11 17:35:31, Ingo Molnar wrote:

* Linus Torvalds [off-list ref] wrote:

quoted

And in addition, I don't see why others wouldn't see it (I've got
DEBUG_PAGEALLOC and SLUB_DEBUG_ON turned on myself, and I know others
do too).

I've done extensive randconfig testing and no crash triggers for typical workloads 
on a typical dual-core PC. If there's a generic crashes in there my tests tend to 
trigger them at least 10x as often as regular testers ;-) But the tests are still 
only statistical so the race could simply be special and missed by the tests.

quoted

So I'm wondering what triggers it. Must be something subtle.

I think what Michal did before he got the corruption seemed somewhat atypical: 
suspend/resume and udevd wifi twiddling, right?

I wouldn't call it atypical. I just resumed from suspend to RAM and set
up my wireless interface which involved modprobe for iwlwifi[*] (where udev
came into play).

---
[*] - my script for setting up home wireless connection rmmods iwlwifi,
iwlcore mac80211 cfg80211 and then modprobes iwlwifi. It is a relict
from the past where I wasn't able to re-establish the connection in some
cases (well stupid router which totally confused the driver) without
reloading modules. I guess this is no more needed but I was lazy to
touch my scripts when they work.
-- 
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic

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