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Subject[PATCH v2] module: check if memory leak by module.
Date
This patch checks if any module which is going to be unloaded
is doing vmalloc memory leak or not.

Logs:-
[ 129.336368] Module [test_module] is getting unloaded before doing vfree
[ 129.336371] Memory still allocated: addr:0xffffc90001461000 - 0xffffc900014c7000, pages 101
[ 129.336376] Allocating function kernel_init+0x1c/0x20 [test_module]

Signed-off-by: Vaneet Narang <v.narang@samsung.com>
Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
---
v1->v2: made code generic rather than dependent on config.
changed pr_alert to pr_err.

include/linux/vmalloc.h | 2 ++
kernel/module.c | 22 ++++++++++++++++++++++
mm/vmalloc.c | 2 --
3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 46991ad..5531af3 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -29,6 +29,8 @@
#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 f953df9..98a8018 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2117,9 +2117,31 @@ void __weak module_arch_freeing_init(struct module *mod)
{
}

+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_err("Module [%s] is getting unloaded before doing vfree\n", mod->name);
+ pr_err("Memory still allocated: addr:0x%lx - 0x%lx, pages %u\n",
+ va->va_start, va->va_end, va->vm->nr_pages);
+ pr_err("Allocating function %pS\n", va->vm->caller);
+ }
+
+ }
+ rcu_read_unlock();
+}
+
/* 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/vmalloc.c b/mm/vmalloc.c
index 68eb002..0166a0a 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -314,8 +314,6 @@ unsigned long vmalloc_to_pfn(const void *vmalloc_addr)

/*** 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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