Messages in this thread | | | Date | Thu, 15 Oct 2009 13:04:23 -0300 | From | Marcelo Tosatti <> | Subject | Re: [PATCH] kvm: Prevent kvm_init from corrupting debugfs structures |
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On Wed, Oct 14, 2009 at 04:21:00PM -0700, 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. > > Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Applied, thanks.
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