Messages in this thread | | | Date | Thu, 15 Oct 2009 16:12:02 +0900 | From | Avi Kivity <> | Subject | Re: [PATCH] kvm: Prevent kvm_init from corrupting debugfs structures |
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On 10/15/2009 08:21 AM, Darrick J. Wong wrote: > I'm seeing an oops condition when kvm-intel and kvm-amd are modprobe'd > during boot (say on an Intel system) and then rmmod'd: > > # modprobe kvm-intel > kvm_init() > kvm_init_debug() > kvm_arch_init()<-- stores debugfs dentries internally > (success, etc) > > # modprobe kvm-amd > kvm_init() > kvm_init_debug()<-- second initialization clobbers kvm's > internal pointers to dentries > kvm_arch_init() > kvm_exit_debug()<-- and frees them > > # rmmod kvm-intel > kvm_exit() > kvm_exit_debug()<-- double free of debugfs files! > > *BOOM* > > If execution gets to the end of kvm_init(), then the calling module has been > established as the kvm provider. Move the debugfs initialization to the end of > the function, and remove the now-unnecessary call to kvm_exit_debug() from the > error path. That way we avoid trampling on the debugfs entries and freeing > them twice. > >
Looks good.
-- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.
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