Re: [2.6.28] NULL pointer dereference at get_stats()
flat view
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date: 2008-12-30 17:02:17
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Hello. Frederik Deweerdt wrote:
Does adding maxcpus=0 to the boot parameters solve the problem? Stephen suspected a per-cpu variable related problem.
No, but I got interestring results. Result | # of virtual CPUs | Kernel command line -------+-------------------+----------------------------------------- OK | 2 | ro root=LABEL=/ BUG | 2 | ro root=LABEL=/ noapic nolapic BUG | 2 | ro root=LABEL=/ noapic nolapic maxcpus=0 BUG | 2 | ro root=LABEL=/ noapic nolapic nosmp BUG | 2 | ro root=LABEL=/ maxcpus=0 BUG | 2 | ro root=LABEL=/ nosmp OK | 1 | ro root=LABEL=/ OK | 1 | ro root=LABEL=/ nolapic noapic OK | 1 | ro root=LABEL=/ nolapic noapic maxcpus=0 OK | 1 | ro root=LABEL=/ nolapic noapic nosmp "OK" means NULL pointer dereference didn't happen. "BUG" means NULL pointer dereference happened. I was adding "noapic" "nolapic" to command line while assigning 2 vcpus. Thus, I encountered this problem. Workaround is to remove "noapic" "nolapic". Now, it seems to me that this problem is caused by interaction of "noapic" "nolapic" "maxcpus=0" "nosmp" options. Regards.