Tell KMSAN that a new task is created, so the tool creates a backing
metadata structure for that task.
Signed-off-by: Alexander Potapenko <[email protected]>
---
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
On Fri, 1 Jul 2022 at 16:24, 'Alexander Potapenko' via kasan-dev
<[email protected]> wrote:
>
> Tell KMSAN that a new task is created, so the tool creates a backing
> metadata structure for that task.
>
> Signed-off-by: Alexander Potapenko <[email protected]>
> ---
> 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);
Why are these EXPORT_SYMBOL? Will they be used from some kernel module?
On Tue, Jul 12, 2022 at 3:18 PM Marco Elver <[email protected]> wrote:
>
> On Fri, 1 Jul 2022 at 16:24, 'Alexander Potapenko' via kasan-dev
> <[email protected]> wrote:
> >
> > Tell KMSAN that a new task is created, so the tool creates a backing
> > metadata structure for that task.
> >
> > Signed-off-by: Alexander Potapenko <[email protected]>
> > ---
> > 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);
>
> Why are these EXPORT_SYMBOL? Will they be used from some kernel module?
You're right, most of them will not. Will fix.