lkml.org 
[lkml]   [2022]   [Jul]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
Subject[PATCH v4 16/45] kmsan: handle task creation and exiting
From
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@google.com>
---
v2:
-- move implementation of kmsan_task_create() and kmsan_task_exit() here

v4:
-- change sizeof(type) to sizeof(*ptr)

Link: https://linux-review.googlesource.com/id/I0f41c3a1c7d66f7e14aabcfdfc7c69addb945805
---
include/linux/kmsan.h | 17 +++++++++++++++++
kernel/exit.c | 2 ++
kernel/fork.c | 2 ++
mm/kmsan/core.c | 10 ++++++++++
mm/kmsan/hooks.c | 19 +++++++++++++++++++
mm/kmsan/kmsan.h | 2 ++
6 files changed, 52 insertions(+)

diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h
index fd76cea338878..b71e2032222e9 100644
--- a/include/linux/kmsan.h
+++ b/include/linux/kmsan.h
@@ -16,6 +16,7 @@

struct page;
struct kmem_cache;
+struct task_struct;

#ifdef CONFIG_KMSAN

@@ -42,6 +43,14 @@ struct kmsan_ctx {
bool allow_reporting;
};

+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().
@@ -163,6 +172,14 @@ 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 f072959fcab7f..1784b7a741ddd 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 9d44f2d46c696..6dfca6f00ec82 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 16fb8880a9c6d..7eabed03ed10b 100644
--- a/mm/kmsan/core.c
+++ b/mm/kmsan/core.c
@@ -44,6 +44,16 @@ 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 052e17b7a717d..43a529569053d 100644
--- a/mm/kmsan/hooks.c
+++ b/mm/kmsan/hooks.c
@@ -26,6 +26,25 @@
* 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();
+}
+EXPORT_SYMBOL(kmsan_task_create);
+
+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;
+}
+EXPORT_SYMBOL(kmsan_task_exit);
+
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 d3c400ca097ba..c7fb8666607e2 100644
--- a/mm/kmsan/kmsan.h
+++ b/mm/kmsan/kmsan.h
@@ -179,6 +179,8 @@ 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);
--
2.37.0.rc0.161.g10f37bed90-goog
\
 
 \ /
  Last update: 2022-07-01 16:26    [W:0.716 / U:0.552 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site