[PATCH v2 1/8] irqbypass: Drop pointless and misleading THIS_MODULE get/put
From: Sean Christopherson <seanjc@google.com>
Date: 2025-05-16 23:07:39
Also in:
kvm, lkml, virtualization
Subsystem:
the rest, virt lib · Maintainers:
Linus Torvalds, Alex Williamson, Paolo Bonzini
Drop irqbypass.ko's superfluous and misleading get/put calls on THIS_MODULE. A module taking a reference to itself is useless; no amount of checks will prevent doom and destruction if the caller hasn't already guaranteed the liveliness of the module (this goes for any module). E.g. if try_module_get() fails because irqbypass.ko is being unloaded, then the kernel has already hit a use-after-free by virtue of executing code whose lifecycle is tied to irqbypass.ko. Reviewed-by: Kevin Tian <kevin.tian@intel.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Sean Christopherson <seanjc@google.com> --- virt/lib/irqbypass.c | 20 -------------------- 1 file changed, 20 deletions(-)
diff --git a/virt/lib/irqbypass.c b/virt/lib/irqbypass.c
index 28fda42e471b..080c706f3b01 100644
--- a/virt/lib/irqbypass.c
+++ b/virt/lib/irqbypass.c@@ -92,9 +92,6 @@ int irq_bypass_register_producer(struct irq_bypass_producer *producer) might_sleep(); - if (!try_module_get(THIS_MODULE)) - return -ENODEV; - mutex_lock(&lock); list_for_each_entry(tmp, &producers, node) {
@@ -120,7 +117,6 @@ int irq_bypass_register_producer(struct irq_bypass_producer *producer) return 0; out_err: mutex_unlock(&lock); - module_put(THIS_MODULE); return ret; } EXPORT_SYMBOL_GPL(irq_bypass_register_producer);
@@ -142,9 +138,6 @@ void irq_bypass_unregister_producer(struct irq_bypass_producer *producer) might_sleep(); - if (!try_module_get(THIS_MODULE)) - return; /* nothing in the list anyway */ - mutex_lock(&lock); list_for_each_entry(tmp, &producers, node) {
@@ -159,13 +152,10 @@ void irq_bypass_unregister_producer(struct irq_bypass_producer *producer) } list_del(&producer->node); - module_put(THIS_MODULE); break; } mutex_unlock(&lock); - - module_put(THIS_MODULE); } EXPORT_SYMBOL_GPL(irq_bypass_unregister_producer);
@@ -188,9 +178,6 @@ int irq_bypass_register_consumer(struct irq_bypass_consumer *consumer) might_sleep(); - if (!try_module_get(THIS_MODULE)) - return -ENODEV; - mutex_lock(&lock); list_for_each_entry(tmp, &consumers, node) {
@@ -216,7 +203,6 @@ int irq_bypass_register_consumer(struct irq_bypass_consumer *consumer) return 0; out_err: mutex_unlock(&lock); - module_put(THIS_MODULE); return ret; } EXPORT_SYMBOL_GPL(irq_bypass_register_consumer);
@@ -238,9 +224,6 @@ void irq_bypass_unregister_consumer(struct irq_bypass_consumer *consumer) might_sleep(); - if (!try_module_get(THIS_MODULE)) - return; /* nothing in the list anyway */ - mutex_lock(&lock); list_for_each_entry(tmp, &consumers, node) {
@@ -255,12 +238,9 @@ void irq_bypass_unregister_consumer(struct irq_bypass_consumer *consumer) } list_del(&consumer->node); - module_put(THIS_MODULE); break; } mutex_unlock(&lock); - - module_put(THIS_MODULE); } EXPORT_SYMBOL_GPL(irq_bypass_unregister_consumer);
--
2.49.0.1112.g889b7c5bd8-goog