diff options
| author | Oliver Upton <oupton@google.com> | 2022-04-06 23:56:13 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-07-12 16:35:04 +0200 |
| commit | e73c0eaf7f3538a23c49d377a4d56758ab269834 (patch) | |
| tree | a96fe7a0f8eec585b73bec4e57472fea93dc5c06 /virt | |
| parent | f3647c369c178c1cdea7f6a60dc32d6118afac40 (diff) | |
KVM: Don't create VM debugfs files outside of the VM directory
[ Upstream commit a44a4cc1c969afec97dbb2aedaf6f38eaa6253bb ]
Unfortunately, there is no guarantee that KVM was able to instantiate a
debugfs directory for a particular VM. To that end, KVM shouldn't even
attempt to create new debugfs files in this case. If the specified
parent dentry is NULL, debugfs_create_file() will instantiate files at
the root of debugfs.
For arm64, it is possible to create the vgic-state file outside of a
VM directory, the file is not cleaned up when a VM is destroyed.
Nonetheless, the corresponding struct kvm is freed when the VM is
destroyed.
Nip the problem in the bud for all possible errant debugfs file
creations by initializing kvm->debugfs_dentry to -ENOENT. In so doing,
debugfs_create_file() will fail instead of creating the file in the root
directory.
Cc: stable@kernel.org
Fixes: 929f45e32499 ("kvm: no need to check return value of debugfs_create functions")
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220406235615.1447180-2-oupton@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/kvm_main.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 99c591569815..9134ae252d7c 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -911,7 +911,7 @@ static void kvm_destroy_vm_debugfs(struct kvm *kvm) int kvm_debugfs_num_entries = kvm_vm_stats_header.num_desc + kvm_vcpu_stats_header.num_desc; - if (!kvm->debugfs_dentry) + if (IS_ERR(kvm->debugfs_dentry)) return; debugfs_remove_recursive(kvm->debugfs_dentry); @@ -934,6 +934,12 @@ static int kvm_create_vm_debugfs(struct kvm *kvm, int fd) int kvm_debugfs_num_entries = kvm_vm_stats_header.num_desc + kvm_vcpu_stats_header.num_desc; + /* + * Force subsequent debugfs file creations to fail if the VM directory + * is not created. + */ + kvm->debugfs_dentry = ERR_PTR(-ENOENT); + if (!debugfs_initialized()) return 0; @@ -5373,7 +5379,7 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm) } add_uevent_var(env, "PID=%d", kvm->userspace_pid); - if (kvm->debugfs_dentry) { + if (!IS_ERR(kvm->debugfs_dentry)) { char *tmp, *p = kmalloc(PATH_MAX, GFP_KERNEL_ACCOUNT); if (p) { |