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 <[email protected]> Signed-off-by: Vaneet Narang <[email protected]> --- 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
