ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 126 insertions, 0 deletions

diff --git a/drivers/virt/acrn/vm.c b/drivers/virt/acrn/vm.c
new file mode 100644
index 000000000..3753b27c5
--- /dev/null
+++ b/drivers/virt/acrn/vm.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ACRN_HSM: Virtual Machine management
+ *
+ * Copyright (C) 2020 Intel Corporation. All rights reserved.
+ *
+ * Authors:
+ *	Jason Chen CJ <jason.cj.chen@intel.com>
+ *	Yakui Zhao <yakui.zhao@intel.com>
+ */
+#include <linux/io.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+
+#include "acrn_drv.h"
+
+/* List of VMs */
+LIST_HEAD(acrn_vm_list);
+/*
+ * acrn_vm_list is read in a worker thread which dispatch I/O requests and
+ * is wrote in VM creation ioctl. Use the rwlock mechanism to protect it.
+ */
+DEFINE_RWLOCK(acrn_vm_list_lock);
+
+struct acrn_vm *acrn_vm_create(struct acrn_vm *vm,
+			       struct acrn_vm_creation *vm_param)
+{
+	int ret;
+
+	ret = hcall_create_vm(virt_to_phys(vm_param));
+	if (ret < 0 || vm_param->vmid == ACRN_INVALID_VMID) {
+		dev_err(acrn_dev.this_device,
+			"Failed to create VM! Error: %d\n", ret);
+		return NULL;
+	}
+
+	mutex_init(&vm->regions_mapping_lock);
+	INIT_LIST_HEAD(&vm->ioreq_clients);
+	spin_lock_init(&vm->ioreq_clients_lock);
+	vm->vmid = vm_param->vmid;
+	vm->vcpu_num = vm_param->vcpu_num;
+
+	if (acrn_ioreq_init(vm, vm_param->ioreq_buf) < 0) {
+		hcall_destroy_vm(vm_param->vmid);
+		vm->vmid = ACRN_INVALID_VMID;
+		return NULL;
+	}
+
+	write_lock_bh(&acrn_vm_list_lock);
+	list_add(&vm->list, &acrn_vm_list);
+	write_unlock_bh(&acrn_vm_list_lock);
+
+	acrn_ioeventfd_init(vm);
+	acrn_irqfd_init(vm);
+	dev_dbg(acrn_dev.this_device, "VM %u created.\n", vm->vmid);
+	return vm;
+}
+
+int acrn_vm_destroy(struct acrn_vm *vm)
+{
+	int ret;
+
+	if (vm->vmid == ACRN_INVALID_VMID ||
+	    test_and_set_bit(ACRN_VM_FLAG_DESTROYED, &vm->flags))
+		return 0;
+
+	ret = hcall_destroy_vm(vm->vmid);
+	if (ret < 0) {
+		dev_err(acrn_dev.this_device,
+			"Failed to destroy VM %u\n", vm->vmid);
+		clear_bit(ACRN_VM_FLAG_DESTROYED, &vm->flags);
+		return ret;
+	}
+
+	/* Remove from global VM list */
+	write_lock_bh(&acrn_vm_list_lock);
+	list_del_init(&vm->list);
+	write_unlock_bh(&acrn_vm_list_lock);
+
+	acrn_ioeventfd_deinit(vm);
+	acrn_irqfd_deinit(vm);
+	acrn_ioreq_deinit(vm);
+
+	if (vm->monitor_page) {
+		put_page(vm->monitor_page);
+		vm->monitor_page = NULL;
+	}
+
+	acrn_vm_all_ram_unmap(vm);
+
+	dev_dbg(acrn_dev.this_device, "VM %u destroyed.\n", vm->vmid);
+	vm->vmid = ACRN_INVALID_VMID;
+	return 0;
+}
+
+/**
+ * acrn_msi_inject() - Inject a MSI interrupt into a User VM
+ * @vm:		User VM
+ * @msi_addr:	The MSI address
+ * @msi_data:	The MSI data
+ *
+ * Return: 0 on success, <0 on error
+ */
+int acrn_msi_inject(struct acrn_vm *vm, u64 msi_addr, u64 msi_data)
+{
+	struct acrn_msi_entry *msi;
+	int ret;
+
+	/* might be used in interrupt context, so use GFP_ATOMIC */
+	msi = kzalloc_obj(*msi, GFP_ATOMIC);
+	if (!msi)
+		return -ENOMEM;
+
+	/*
+	 * msi_addr: addr[19:12] with dest vcpu id
+	 * msi_data: data[7:0] with vector
+	 */
+	msi->msi_addr = msi_addr;
+	msi->msi_data = msi_data;
+	ret = hcall_inject_msi(vm->vmid, virt_to_phys(msi));
+	if (ret < 0)
+		dev_err(acrn_dev.this_device,
+			"Failed to inject MSI to VM %u!\n", vm->vmid);
+	kfree(msi);
+	return ret;
+}