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Message-ID: <20220826150807.723137-17-glider@google.com>
Date: Fri, 26 Aug 2022 17:07:39 +0200
From: Alexander Potapenko <glider@...gle.com>
To: glider@...gle.com
Cc: Alexander Viro <viro@...iv.linux.org.uk>,
Alexei Starovoitov <ast@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Andrey Konovalov <andreyknvl@...gle.com>,
Andy Lutomirski <luto@...nel.org>,
Arnd Bergmann <arnd@...db.de>, Borislav Petkov <bp@...en8.de>,
Christoph Hellwig <hch@....de>,
Christoph Lameter <cl@...ux.com>,
David Rientjes <rientjes@...gle.com>,
Dmitry Vyukov <dvyukov@...gle.com>,
Eric Dumazet <edumazet@...gle.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Herbert Xu <herbert@...dor.apana.org.au>,
Ilya Leoshkevich <iii@...ux.ibm.com>,
Ingo Molnar <mingo@...hat.com>, Jens Axboe <axboe@...nel.dk>,
Joonsoo Kim <iamjoonsoo.kim@....com>,
Kees Cook <keescook@...omium.org>,
Marco Elver <elver@...gle.com>,
Mark Rutland <mark.rutland@....com>,
Matthew Wilcox <willy@...radead.org>,
"Michael S. Tsirkin" <mst@...hat.com>,
Pekka Enberg <penberg@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Petr Mladek <pmladek@...e.com>,
Steven Rostedt <rostedt@...dmis.org>,
Thomas Gleixner <tglx@...utronix.de>,
Vasily Gorbik <gor@...ux.ibm.com>,
Vegard Nossum <vegard.nossum@...cle.com>,
Vlastimil Babka <vbabka@...e.cz>, kasan-dev@...glegroups.com,
linux-mm@...ck.org, linux-arch@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH v5 16/44] kmsan: handle task creation and exiting
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@...gle.com>
---
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 fd76cea338878..5ec056380a43b 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 +43,18 @@ struct kmsan_ctx {
bool allow_reporting;
};
+/**
+ * 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().
@@ -163,6 +176,14 @@ 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 90c85b17bf698..7cf3eea01ceef 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 a5dec6e62b4ef..a640e0cccbb64 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 519a7a1dcb4aa..4ab8c629acd0c 100644
--- a/mm/kmsan/hooks.c
+++ b/mm/kmsan/hooks.c
@@ -26,6 +26,23 @@
* 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 6b9deee3b7f32..04954b83c5d65 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);
--
2.37.2.672.g94769d06f0-goog
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