* Allocate pages if THREAD_SIZE is >= PAGE_SIZE, otherwise use a
* kmemcache based allocator.
*/
-# if THREAD_SIZE >= PAGE_SIZE
-static unsigned long *alloc_thread_stack_node(struct task_struct *tsk,
- int node)
+# if THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK)
+
+#ifdef CONFIG_VMAP_STACK
+/*
+ * vmalloc() is a bit slow, and calling vfree() enough times will force a TLB
+ * flush. Try to minimize the number of calls by caching stacks.
+ */
+#define NR_CACHED_STACKS 2
+static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]);
+#endif
+
+static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
{
+#ifdef CONFIG_VMAP_STACK
+ void *stack;
+ int i;
+
+ local_irq_disable();
+ for (i = 0; i < NR_CACHED_STACKS; i++) {
+ struct vm_struct *s = this_cpu_read(cached_stacks[i]);
+
+ if (!s)
+ continue;
+ this_cpu_write(cached_stacks[i], NULL);
+
+ tsk->stack_vm_area = s;
+ local_irq_enable();
+ return s->addr;
+ }
+ local_irq_enable();
+
+ stack = __vmalloc_node_range(THREAD_SIZE, THREAD_SIZE,
+ VMALLOC_START, VMALLOC_END,
+ THREADINFO_GFP | __GFP_HIGHMEM,
+ PAGE_KERNEL,
+ 0, node, __builtin_return_address(0));
+
+ /*
+ * We can't call find_vm_area() in interrupt context, and
+ * free_thread_stack() can be called in interrupt context,
+ * so cache the vm_struct.
+ */
+ if (stack)
+ tsk->stack_vm_area = find_vm_area(stack);
+ return stack;
+#else
struct page *page = alloc_pages_node(node, THREADINFO_GFP,
THREAD_SIZE_ORDER);
return page ? page_address(page) : NULL;
+#endif
}
-static inline void free_thread_stack(unsigned long *stack)
+static inline void free_thread_stack(struct task_struct *tsk)
{
- __free_pages(virt_to_page(stack), THREAD_SIZE_ORDER);
+#ifdef CONFIG_VMAP_STACK
+ if (task_stack_vm_area(tsk)) {
+ unsigned long flags;
+ int i;
+
+ local_irq_save(flags);
+ for (i = 0; i < NR_CACHED_STACKS; i++) {
+ if (this_cpu_read(cached_stacks[i]))
+ continue;
+
+ this_cpu_write(cached_stacks[i], tsk->stack_vm_area);
+ local_irq_restore(flags);
+ return;
+ }
+ local_irq_restore(flags);
+
+ vfree(tsk->stack);
+ return;
+ }
+#endif
+
+ __free_pages(virt_to_page(tsk->stack), THREAD_SIZE_ORDER);
}
# else
static struct kmem_cache *thread_stack_cache;
return kmem_cache_alloc_node(thread_stack_cache, THREADINFO_GFP, node);
}
-static void free_thread_stack(unsigned long *stack)
+static void free_thread_stack(struct task_struct *tsk)
{
- kmem_cache_free(thread_stack_cache, stack);
+ kmem_cache_free(thread_stack_cache, tsk->stack);
}
void thread_stack_cache_init(void)
/* SLAB cache for mm_struct structures (tsk->mm) */
static struct kmem_cache *mm_cachep;
-static void account_kernel_stack(unsigned long *stack, int account)
+static void account_kernel_stack(struct task_struct *tsk, int account)
{
- /* All stack pages are in the same zone and belong to the same memcg. */
- struct page *first_page = virt_to_page(stack);
+ void *stack = task_stack_page(tsk);
+ struct vm_struct *vm = task_stack_vm_area(tsk);
+
+ BUILD_BUG_ON(IS_ENABLED(CONFIG_VMAP_STACK) && PAGE_SIZE % 1024 != 0);
+
+ if (vm) {
+ int i;
+
+ BUG_ON(vm->nr_pages != THREAD_SIZE / PAGE_SIZE);
+
+ for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) {
+ mod_zone_page_state(page_zone(vm->pages[i]),
+ NR_KERNEL_STACK_KB,
+ PAGE_SIZE / 1024 * account);
+ }
+
+ /* All stack pages belong to the same memcg. */
+ memcg_kmem_update_page_stat(vm->pages[0], MEMCG_KERNEL_STACK_KB,
+ account * (THREAD_SIZE / 1024));
+ } else {
+ /*
+ * All stack pages are in the same zone and belong to the
+ * same memcg.
+ */
+ struct page *first_page = virt_to_page(stack);
- mod_zone_page_state(page_zone(first_page), NR_KERNEL_STACK_KB,
- THREAD_SIZE / 1024 * account);
+ mod_zone_page_state(page_zone(first_page), NR_KERNEL_STACK_KB,
+ THREAD_SIZE / 1024 * account);
- memcg_kmem_update_page_stat(
- first_page, MEMCG_KERNEL_STACK_KB,
- account * (THREAD_SIZE / 1024));
+ memcg_kmem_update_page_stat(first_page, MEMCG_KERNEL_STACK_KB,
+ account * (THREAD_SIZE / 1024));
+ }
}
-void free_task(struct task_struct *tsk)
+static void release_task_stack(struct task_struct *tsk)
{
- account_kernel_stack(tsk->stack, -1);
+ account_kernel_stack(tsk, -1);
arch_release_thread_stack(tsk->stack);
- free_thread_stack(tsk->stack);
+ free_thread_stack(tsk);
+ tsk->stack = NULL;
+#ifdef CONFIG_VMAP_STACK
+ tsk->stack_vm_area = NULL;
+#endif
+}
+
+#ifdef CONFIG_THREAD_INFO_IN_TASK
+void put_task_stack(struct task_struct *tsk)
+{
+ if (atomic_dec_and_test(&tsk->stack_refcount))
+ release_task_stack(tsk);
+}
+#endif
+
+void free_task(struct task_struct *tsk)
+{
+#ifndef CONFIG_THREAD_INFO_IN_TASK
+ /*
+ * The task is finally done with both the stack and thread_info,
+ * so free both.
+ */
+ release_task_stack(tsk);
+#else
+ /*
+ * If the task had a separate stack allocation, it should be gone
+ * by now.
+ */
+ WARN_ON_ONCE(atomic_read(&tsk->stack_refcount) != 0);
+#endif
rt_mutex_debug_task_free(tsk);
ftrace_graph_exit_task(tsk);
put_seccomp_filter(tsk);
{
struct task_struct *tsk;
unsigned long *stack;
+ struct vm_struct *stack_vm_area;
int err;
if (node == NUMA_NO_NODE)
if (!stack)
goto free_tsk;
+ stack_vm_area = task_stack_vm_area(tsk);
+
err = arch_dup_task_struct(tsk, orig);
+
+ /*
+ * arch_dup_task_struct() clobbers the stack-related fields. Make
+ * sure they're properly initialized before using any stack-related
+ * functions again.
+ */
+ tsk->stack = stack;
+#ifdef CONFIG_VMAP_STACK
+ tsk->stack_vm_area = stack_vm_area;
+#endif
+#ifdef CONFIG_THREAD_INFO_IN_TASK
+ atomic_set(&tsk->stack_refcount, 1);
+#endif
+
if (err)
goto free_stack;
- tsk->stack = stack;
#ifdef CONFIG_SECCOMP
/*
* We must handle setting up seccomp filters once we're under
tsk->task_frag.page = NULL;
tsk->wake_q.next = NULL;
- account_kernel_stack(stack, 1);
+ account_kernel_stack(tsk, 1);
kcov_task_init(tsk);
return tsk;
free_stack:
- free_thread_stack(stack);
+ free_thread_stack(tsk);
free_tsk:
free_task_struct(tsk);
return NULL;
}
EXPORT_SYMBOL(get_mm_exe_file);
+/**
+ * get_task_exe_file - acquire a reference to the task's executable file
+ *
+ * Returns %NULL if task's mm (if any) has no associated executable file or
+ * this is a kernel thread with borrowed mm (see the comment above get_task_mm).
+ * User must release file via fput().
+ */
+struct file *get_task_exe_file(struct task_struct *task)
+{
+ struct file *exe_file = NULL;
+ struct mm_struct *mm;
+
+ task_lock(task);
+ mm = task->mm;
+ if (mm) {
+ if (!(task->flags & PF_KTHREAD))
+ exe_file = get_mm_exe_file(mm);
+ }
+ task_unlock(task);
+ return exe_file;
+}
+EXPORT_SYMBOL(get_task_exe_file);
+
/**
* get_task_mm - acquire a reference to the task's mm
*
deactivate_mm(tsk, mm);
/*
- * If we're exiting normally, clear a user-space tid field if
- * requested. We leave this alone when dying by signal, to leave
- * the value intact in a core dump, and to save the unnecessary
- * trouble, say, a killed vfork parent shouldn't touch this mm.
- * Userland only wants this done for a sys_exit.
+ * Signal userspace if we're not exiting with a core dump
+ * because we want to leave the value intact for debugging
+ * purposes.
*/
if (tsk->clear_child_tid) {
- if (!(tsk->flags & PF_SIGNALED) &&
+ if (!(tsk->signal->flags & SIGNAL_GROUP_COREDUMP) &&
atomic_read(&mm->mm_users) > 1) {
/*
* We don't check the error code - if userspace has
p->real_start_time = ktime_get_boot_ns();
p->io_context = NULL;
p->audit_context = NULL;
- threadgroup_change_begin(current);
cgroup_fork(p);
#ifdef CONFIG_NUMA
p->mempolicy = mpol_dup(p->mempolicy);
INIT_LIST_HEAD(&p->thread_group);
p->task_works = NULL;
+ threadgroup_change_begin(current);
/*
* Ensure that the cgroup subsystem policies allow the new process to be
* forked. It should be noted the the new process's css_set can be changed
bad_fork_cancel_cgroup:
cgroup_cancel_fork(p);
bad_fork_free_pid:
+ threadgroup_change_end(current);
if (pid != &init_struct_pid)
free_pid(pid);
bad_fork_cleanup_thread:
mpol_put(p->mempolicy);
bad_fork_cleanup_threadgroup_lock:
#endif
- threadgroup_change_end(current);
delayacct_tsk_free(p);
bad_fork_cleanup_count:
atomic_dec(&p->cred->user->processes);
exit_creds(p);
bad_fork_free:
+ put_task_stack(p);
free_task(p);
fork_out:
return ERR_PTR(retval);
projects / cascardo / linux.git / blobdiff