This patch adds new config VMALLOC_MEMORY_LEAK to check if any
module which is going to be unloaded is doing vmalloc memory leak.
Logs:-
[ 129.336368] Module vmalloc is getting unloaded before doing vfree
[ 129.336371] Memory still allocated: addr:0xffffc90001461000 - 0xffffc900014c7000, pages 101
[ 129.336376] Allocating function kernel_init+0x1c/0x20 [vmalloc]
Signed-off-by: Maninder Singh <maninder1.s@xxxxxxxxxxx>
Signed-off-by: Vaneet Narang <v.narang@xxxxxxxxxxx>
---
include/linux/vmalloc.h | 2 ++
kernel/module.c | 28 ++++++++++++++++++++++++++++
mm/Kconfig.debug | 7 +++++++
mm/vmalloc.c | 2 --
4 files changed, 37 insertions(+), 2 deletions(-)
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 3d9d786..abfc03c 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -29,6 +29,8 @@ struct notifier_block; /* in notifier.h */
#define IOREMAP_MAX_ORDER (7 + PAGE_SHIFT) /* 128 pages */
#endif
+#define VM_VM_AREA 0x04
+
struct vm_struct {
struct vm_struct *next;
void *addr;
diff --git a/kernel/module.c b/kernel/module.c
index 529efae..b492f34 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2082,9 +2082,37 @@ void __weak module_arch_freeing_init(struct module *mod)
{
}
+#ifdef CONFIG_VMALLOC_MEMORY_LEAK
+static void check_memory_leak(struct module *mod)
+{
+ struct vmap_area *va;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(va, &vmap_area_list, list) {
+ if (!(va->flags & VM_VM_AREA))
+ continue;
+ if ((mod->core_layout.base < va->vm->caller) &&
+ (mod->core_layout.base + mod->core_layout.size) > va->vm->caller) {
+ pr_alert("Module %s is getting unloaded before doing vfree\n", mod->name);
+ pr_alert("Memory still allocated: addr:0x%lx - 0x%lx, pages %u\n",
+ va->va_start, va->va_end, va->vm->nr_pages);
+ pr_alert("Allocating function %pS\n", va->vm->caller);
+ }
+
+ }
+ rcu_read_unlock();
+}
+#else
+static inline void check_memory_leak(struct module *mod)
+{
+}
+#endif
+
/* Free a module, remove from lists, etc. */
static void free_module(struct module *mod)
{
+ check_memory_leak(mod);
+
trace_module_free(mod);
mod_sysfs_teardown(mod);
diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug
index 22f4cd9..0bead5d 100644
--- a/mm/Kconfig.debug
+++ b/mm/Kconfig.debug
@@ -92,3 +92,10 @@ config DEBUG_PAGE_REF
careful when enabling this feature because it adds about 30 KB to the
kernel code. However the runtime performance overhead is virtually
nil until the tracepoints are actually enabled.
+
+config VMALLOC_MEMORY_LEAK
+ bool "Enable to check memory leaks by modules"
+ default n
+ ---help---
+ This is a feature to check if any module has allocated memory using vmalloc
+ but getting unloaded without doing vfree.
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 91f44e7..7fba87a 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -275,8 +275,6 @@ EXPORT_SYMBOL(vmalloc_to_pfn);
/*** Global kva allocator ***/
-#define VM_VM_AREA 0x04
-
static DEFINE_SPINLOCK(vmap_area_lock);
/* Export for kexec only */
LIST_HEAD(vmap_area_list);
--
1.9.1
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