patches/old/kmsan-handle-task-creation-and-exiting.patch

From: Alexander Potapenko <glider@google.com>
Subject: kmsan: handle task creation and exiting
Date: Thu, 15 Sep 2022 17:03:50 +0200

Tell KMSAN that a new task is created, so the tool creates a backing
metadata structure for that task.

Link: https://lkml.kernel.org/r/20220915150417.722975-17-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 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(+)

--- a/include/linux/kmsan.h~kmsan-handle-task-creation-and-exiting
+++ a/include/linux/kmsan.h
@@ -15,10 +15,23 @@
 
 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().
  * @order: order of allocated struct page.
@@ -139,6 +152,14 @@ void kmsan_iounmap_page_range(unsigned l
 
 #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)
 {
--- a/kernel/exit.c~kmsan-handle-task-creation-and-exiting
+++ a/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>
@@ -742,6 +743,7 @@ 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);
--- a/kernel/fork.c~kmsan-handle-task-creation-and-exiting
+++ a/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>
@@ -1023,6 +1024,7 @@ static struct task_struct *dup_task_stru
 	tsk->worker_private = NULL;
 
 	kcov_task_init(tsk);
+	kmsan_task_create(tsk);
 	kmap_local_fork(tsk);
 
 #ifdef CONFIG_FAULT_INJECTION
--- a/mm/kmsan/core.c~kmsan-handle-task-creation-and-exiting
+++ a/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)
 {
--- a/mm/kmsan/hooks.c~kmsan-handle-task-creation-and-exiting
+++ a/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))
--- a/mm/kmsan/kmsan.h~kmsan-handle-task-creation-and-exiting
+++ a/mm/kmsan/kmsan.h
@@ -180,6 +180,8 @@ void kmsan_internal_set_shadow_origin(vo
 				      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);
_