diff options
| author | Darrick J. Wong <djwong@us.ibm.com> | 2009-11-06 12:00:51 -0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-11-09 16:23:10 -0800 |
| commit | 6fa5a4d48a5cb7aa452cc34120f9122301ec8c93 (patch) | |
| tree | 43190636e41db59b1cbdaeb6091a15a02c0ef85e | |
| parent | 77608cc64e305111725bbefe7d238d9f6da38c5d (diff) | |
KVM: Prevent kvm_init from corrupting debugfs structures
commit: 0ea4ed8e948c30f88c824c973ee4b9529015fe65 upstream
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>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | virt/kvm/kvm_main.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 2884baf1d5f..198c750aa85 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2590,8 +2590,6 @@ int kvm_init(void *opaque, unsigned int vcpu_size, int r; int cpu; - kvm_init_debug(); - r = kvm_arch_init(opaque); if (r) goto out_fail; @@ -2658,6 +2656,8 @@ int kvm_init(void *opaque, unsigned int vcpu_size, kvm_preempt_ops.sched_in = kvm_sched_in; kvm_preempt_ops.sched_out = kvm_sched_out; + kvm_init_debug(); + return 0; out_free: @@ -2679,7 +2679,6 @@ out_free_0: __free_page(bad_page); out: kvm_arch_exit(); - kvm_exit_debug(); out_fail: return r; } @@ -2688,6 +2687,7 @@ EXPORT_SYMBOL_GPL(kvm_init); void kvm_exit(void) { kvm_trace_cleanup(); + kvm_exit_debug(); misc_deregister(&kvm_dev); kmem_cache_destroy(kvm_vcpu_cache); sysdev_unregister(&kvm_sysdev); @@ -2697,7 +2697,6 @@ void kvm_exit(void) on_each_cpu(hardware_disable, NULL, 1); kvm_arch_hardware_unsetup(); kvm_arch_exit(); - kvm_exit_debug(); free_cpumask_var(cpus_hardware_enabled); __free_page(bad_page); } |