Tell KMSAN that a new task is created, so the tool creates a backing metadata structure for that task. Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx> --- v2: -- move implementation of kmsan_task_create() and kmsan_task_exit() here v4: -- change sizeof(type) to sizeof(*ptr) v5: -- do not export KMSAN hooks that are not called from modules -- minor comment fix Link: https://linux-review.googlesource.com/id/I0f41c3a1c7d66f7e14aabcfdfc7c69addb945805 --- include/linux/kmsan.h | 21 +++++++++++++++++++++ kernel/exit.c | 2 ++ kernel/fork.c | 2 ++ mm/kmsan/core.c | 10 ++++++++++ mm/kmsan/hooks.c | 17 +++++++++++++++++ mm/kmsan/kmsan.h | 2 ++ 6 files changed, 54 insertions(+) diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h index 5c4e0079054e6..354aee6f7b1a2 100644 --- a/include/linux/kmsan.h +++ b/include/linux/kmsan.h @@ -15,9 +15,22 @@ struct page; struct kmem_cache; +struct task_struct; #ifdef CONFIG_KMSAN +/** + * kmsan_task_create() - Initialize KMSAN state for the task. + * @task: task to initialize. + */ +void kmsan_task_create(struct task_struct *task); + +/** + * kmsan_task_exit() - Notify KMSAN that a task has exited. + * @task: task about to finish. + */ +void kmsan_task_exit(struct task_struct *task); + /** * kmsan_alloc_page() - Notify KMSAN about an alloc_pages() call. * @page: struct page pointer returned by alloc_pages(). @@ -139,6 +152,14 @@ void kmsan_iounmap_page_range(unsigned long start, unsigned long end); #else +static inline void kmsan_task_create(struct task_struct *task) +{ +} + +static inline void kmsan_task_exit(struct task_struct *task) +{ +} + static inline int kmsan_alloc_page(struct page *page, unsigned int order, gfp_t flags) { diff --git a/kernel/exit.c b/kernel/exit.c index 84021b24f79e3..f5d620c315662 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -60,6 +60,7 @@ #include <linux/writeback.h> #include <linux/shm.h> #include <linux/kcov.h> +#include <linux/kmsan.h> #include <linux/random.h> #include <linux/rcuwait.h> #include <linux/compat.h> @@ -741,6 +742,7 @@ void __noreturn do_exit(long code) WARN_ON(tsk->plug); kcov_task_exit(tsk); + kmsan_task_exit(tsk); coredump_task_exit(tsk); ptrace_event(PTRACE_EVENT_EXIT, code); diff --git a/kernel/fork.c b/kernel/fork.c index 8a9e92068b150..a438f5ee3aed5 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -37,6 +37,7 @@ #include <linux/fdtable.h> #include <linux/iocontext.h> #include <linux/key.h> +#include <linux/kmsan.h> #include <linux/binfmts.h> #include <linux/mman.h> #include <linux/mmu_notifier.h> @@ -1026,6 +1027,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node) tsk->worker_private = NULL; kcov_task_init(tsk); + kmsan_task_create(tsk); kmap_local_fork(tsk); #ifdef CONFIG_FAULT_INJECTION diff --git a/mm/kmsan/core.c b/mm/kmsan/core.c index 5330138fda5bc..112dce135c7f6 100644 --- a/mm/kmsan/core.c +++ b/mm/kmsan/core.c @@ -37,6 +37,16 @@ bool kmsan_enabled __read_mostly; */ DEFINE_PER_CPU(struct kmsan_ctx, kmsan_percpu_ctx); +void kmsan_internal_task_create(struct task_struct *task) +{ + struct kmsan_ctx *ctx = &task->kmsan_ctx; + struct thread_info *info = current_thread_info(); + + __memset(ctx, 0, sizeof(*ctx)); + ctx->allow_reporting = true; + kmsan_internal_unpoison_memory(info, sizeof(*info), false); +} + void kmsan_internal_poison_memory(void *address, size_t size, gfp_t flags, unsigned int poison_flags) { diff --git a/mm/kmsan/hooks.c b/mm/kmsan/hooks.c index 000703c563a4d..6f3e64b0b61f8 100644 --- a/mm/kmsan/hooks.c +++ b/mm/kmsan/hooks.c @@ -27,6 +27,23 @@ * skipping effects of functions like memset() inside instrumented code. */ +void kmsan_task_create(struct task_struct *task) +{ + kmsan_enter_runtime(); + kmsan_internal_task_create(task); + kmsan_leave_runtime(); +} + +void kmsan_task_exit(struct task_struct *task) +{ + struct kmsan_ctx *ctx = &task->kmsan_ctx; + + if (!kmsan_enabled || kmsan_in_runtime()) + return; + + ctx->allow_reporting = false; +} + void kmsan_slab_alloc(struct kmem_cache *s, void *object, gfp_t flags) { if (unlikely(object == NULL)) diff --git a/mm/kmsan/kmsan.h b/mm/kmsan/kmsan.h index 97d48b45dba58..77ee068c04ae9 100644 --- a/mm/kmsan/kmsan.h +++ b/mm/kmsan/kmsan.h @@ -180,6 +180,8 @@ void kmsan_internal_set_shadow_origin(void *address, size_t size, int b, u32 origin, bool checked); depot_stack_handle_t kmsan_internal_chain_origin(depot_stack_handle_t id); +void kmsan_internal_task_create(struct task_struct *task); + bool kmsan_metadata_is_contiguous(void *addr, size_t size); void kmsan_internal_check_memory(void *addr, size_t size, const void *user_addr, int reason); -- 2.37.2.789.g6183377224-goog
