From f1675103e0f361f4f636438c1c911dbe83f5f334 Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Fri, 14 Jan 2022 14:04:11 -0800 Subject: [PATCH] mm: defer kmemleak object creation of module_alloc() [ Upstream commit 60115fa54ad7b913b7cb5844e6b7ffeb842d55f2 ] Yongqiang reports a kmemleak panic when module insmod/rmmod with KASAN enabled(without KASAN_VMALLOC) on x86[1]. When the module area allocates memory, it's kmemleak_object is created successfully, but the KASAN shadow memory of module allocation is not ready, so when kmemleak scan the module's pointer, it will panic due to no shadow memory with KASAN check. module_alloc __vmalloc_node_range kmemleak_vmalloc kmemleak_scan update_checksum kasan_module_alloc kmemleak_ignore Note, there is no problem if KASAN_VMALLOC enabled, the modules area entire shadow memory is preallocated. Thus, the bug only exits on ARCH which supports dynamic allocation of module area per module load, for now, only x86/arm64/s390 are involved. Add a VM_DEFER_KMEMLEAK flags, defer vmalloc'ed object register of kmemleak in module_alloc() to fix this issue. [1] https://lore.kernel.org/all/6d41e2b9-4692-5ec4-b1cd-cbe29ae89739@huawei.com/ [wangkefeng.wang@huawei.com: fix build] Link: https://lkml.kernel.org/r/20211125080307.27225-1-wangkefeng.wang@huawei.com [akpm@linux-foundation.org: simplify ifdefs, per Andrey] Link: https://lkml.kernel.org/r/CA+fCnZcnwJHUQq34VuRxpdoY6_XbJCDJ-jopksS5Eia4PijPzw@mail.gmail.com Link: https://lkml.kernel.org/r/20211124142034.192078-1-wangkefeng.wang@huawei.com Fixes: 793213a82de4 ("s390/kasan: dynamic shadow mem allocation for modules") Fixes: 39d114ddc682 ("arm64: add KASAN support") Fixes: bebf56a1b176 ("kasan: enable instrumentation of global variables") Signed-off-by: Kefeng Wang Reported-by: Yongqiang Liu Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Catalin Marinas Cc: Will Deacon Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Christian Borntraeger Cc: Alexander Gordeev Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: Alexander Potapenko Cc: Kefeng Wang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- arch/arm64/kernel/module.c | 4 ++-- arch/s390/kernel/module.c | 5 +++-- arch/x86/kernel/module.c | 7 ++++--- include/linux/kasan.h | 4 ++-- include/linux/vmalloc.h | 7 +++++++ mm/kasan/shadow.c | 9 +++++++-- mm/vmalloc.c | 3 ++- 7 files changed, 27 insertions(+), 12 deletions(-) diff --git a/arch/arm64/kernel/module.c b/arch/arm64/kernel/module.c index b5ec010c481f..309a27553c87 100644 --- a/arch/arm64/kernel/module.c +++ b/arch/arm64/kernel/module.c @@ -36,7 +36,7 @@ void *module_alloc(unsigned long size) module_alloc_end = MODULES_END; p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base, - module_alloc_end, gfp_mask, PAGE_KERNEL, 0, + module_alloc_end, gfp_mask, PAGE_KERNEL, VM_DEFER_KMEMLEAK, NUMA_NO_NODE, __builtin_return_address(0)); if (!p && IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) && @@ -58,7 +58,7 @@ void *module_alloc(unsigned long size) PAGE_KERNEL, 0, NUMA_NO_NODE, __builtin_return_address(0)); - if (p && (kasan_module_alloc(p, size) < 0)) { + if (p && (kasan_module_alloc(p, size, gfp_mask) < 0)) { vfree(p); return NULL; } diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c index a805ea5cb92d..b032e556eeb7 100644 --- a/arch/s390/kernel/module.c +++ b/arch/s390/kernel/module.c @@ -37,14 +37,15 @@ void *module_alloc(unsigned long size) { + gfp_t gfp_mask = GFP_KERNEL; void *p; if (PAGE_ALIGN(size) > MODULES_LEN) return NULL; p = __vmalloc_node_range(size, MODULE_ALIGN, MODULES_VADDR, MODULES_END, - GFP_KERNEL, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, + gfp_mask, PAGE_KERNEL_EXEC, VM_DEFER_KMEMLEAK, NUMA_NO_NODE, __builtin_return_address(0)); - if (p && (kasan_module_alloc(p, size) < 0)) { + if (p && (kasan_module_alloc(p, size, gfp_mask) < 0)) { vfree(p); return NULL; } diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c index 5e9a34b5bd74..867a341a0c7e 100644 --- a/arch/x86/kernel/module.c +++ b/arch/x86/kernel/module.c @@ -67,6 +67,7 @@ static unsigned long int get_module_load_offset(void) void *module_alloc(unsigned long size) { + gfp_t gfp_mask = GFP_KERNEL; void *p; if (PAGE_ALIGN(size) > MODULES_LEN) @@ -74,10 +75,10 @@ void *module_alloc(unsigned long size) p = __vmalloc_node_range(size, MODULE_ALIGN, MODULES_VADDR + get_module_load_offset(), - MODULES_END, GFP_KERNEL, - PAGE_KERNEL, 0, NUMA_NO_NODE, + MODULES_END, gfp_mask, + PAGE_KERNEL, VM_DEFER_KMEMLEAK, NUMA_NO_NODE, __builtin_return_address(0)); - if (p && (kasan_module_alloc(p, size) < 0)) { + if (p && (kasan_module_alloc(p, size, gfp_mask) < 0)) { vfree(p); return NULL; } diff --git a/include/linux/kasan.h b/include/linux/kasan.h index dd874a1ee862..f407e937241a 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -461,12 +461,12 @@ static inline void kasan_release_vmalloc(unsigned long start, * allocations with real shadow memory. With KASAN vmalloc, the special * case is unnecessary, as the work is handled in the generic case. */ -int kasan_module_alloc(void *addr, size_t size); +int kasan_module_alloc(void *addr, size_t size, gfp_t gfp_mask); void kasan_free_shadow(const struct vm_struct *vm); #else /* (CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS) && !CONFIG_KASAN_VMALLOC */ -static inline int kasan_module_alloc(void *addr, size_t size) { return 0; } +static inline int kasan_module_alloc(void *addr, size_t size, gfp_t gfp_mask) { return 0; } static inline void kasan_free_shadow(const struct vm_struct *vm) {} #endif /* (CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS) && !CONFIG_KASAN_VMALLOC */ diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index 671d402c3778..4fe9e885bbfa 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -28,6 +28,13 @@ struct notifier_block; /* in notifier.h */ #define VM_MAP_PUT_PAGES 0x00000200 /* put pages and free array in vfree */ #define VM_NO_HUGE_VMAP 0x00000400 /* force PAGE_SIZE pte mapping */ +#if (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) && \ + !defined(CONFIG_KASAN_VMALLOC) +#define VM_DEFER_KMEMLEAK 0x00000800 /* defer kmemleak object creation */ +#else +#define VM_DEFER_KMEMLEAK 0 +#endif + /* * VM_KASAN is used slightly differently depending on CONFIG_KASAN_VMALLOC. * diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c index 8d95ee52d019..dd79840e6096 100644 --- a/mm/kasan/shadow.c +++ b/mm/kasan/shadow.c @@ -493,7 +493,7 @@ void kasan_release_vmalloc(unsigned long start, unsigned long end, #else /* CONFIG_KASAN_VMALLOC */ -int kasan_module_alloc(void *addr, size_t size) +int kasan_module_alloc(void *addr, size_t size, gfp_t gfp_mask) { void *ret; size_t scaled_size; @@ -515,9 +515,14 @@ int kasan_module_alloc(void *addr, size_t size) __builtin_return_address(0)); if (ret) { + struct vm_struct *vm = find_vm_area(addr); __memset(ret, KASAN_SHADOW_INIT, shadow_size); - find_vm_area(addr)->flags |= VM_KASAN; + vm->flags |= VM_KASAN; kmemleak_ignore(ret); + + if (vm->flags & VM_DEFER_KMEMLEAK) + kmemleak_vmalloc(vm, size, gfp_mask); + return 0; } diff --git a/mm/vmalloc.c b/mm/vmalloc.c index e8a807c78110..8375eecc55de 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -3032,7 +3032,8 @@ again: clear_vm_uninitialized_flag(area); size = PAGE_ALIGN(size); - kmemleak_vmalloc(area, size, gfp_mask); + if (!(vm_flags & VM_DEFER_KMEMLEAK)) + kmemleak_vmalloc(area, size, gfp_mask); return addr;