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-rw-r--r--kernel/fork.c268
1 files changed, 73 insertions, 195 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index 933e60ebccae..7ce2ebe84796 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -23,18 +23,22 @@
#include <linux/sem.h>
#include <linux/file.h>
#include <linux/fdtable.h>
+#include <linux/iocontext.h>
#include <linux/key.h>
#include <linux/binfmts.h>
#include <linux/mman.h>
+#include <linux/mmu_notifier.h>
#include <linux/fs.h>
#include <linux/nsproxy.h>
#include <linux/capability.h>
#include <linux/cpu.h>
#include <linux/cgroup.h>
#include <linux/security.h>
+#include <linux/hugetlb.h>
#include <linux/swap.h>
#include <linux/syscalls.h>
#include <linux/jiffies.h>
+#include <linux/tracehook.h>
#include <linux/futex.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/rcupdate.h>
@@ -91,6 +95,23 @@ int nr_processes(void)
static struct kmem_cache *task_struct_cachep;
#endif
+#ifndef __HAVE_ARCH_THREAD_INFO_ALLOCATOR
+static inline struct thread_info *alloc_thread_info(struct task_struct *tsk)
+{
+#ifdef CONFIG_DEBUG_STACK_USAGE
+ gfp_t mask = GFP_KERNEL | __GFP_ZERO;
+#else
+ gfp_t mask = GFP_KERNEL;
+#endif
+ return (struct thread_info *)__get_free_pages(mask, THREAD_SIZE_ORDER);
+}
+
+static inline void free_thread_info(struct thread_info *ti)
+{
+ free_pages((unsigned long)ti, THREAD_SIZE_ORDER);
+}
+#endif
+
/* SLAB cache for signal_struct structures (tsk->signal) */
static struct kmem_cache *signal_cachep;
@@ -306,6 +327,14 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
}
/*
+ * Clear hugetlb-related page reserves for children. This only
+ * affects MAP_PRIVATE mappings. Faults generated by the child
+ * are not guaranteed to succeed, even if read-only
+ */
+ if (is_vm_hugetlb_page(tmp))
+ reset_vma_resv_huge_pages(tmp);
+
+ /*
* Link in the new vma and copy the page table entries.
*/
*pprev = tmp;
@@ -373,7 +402,7 @@ static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p)
INIT_LIST_HEAD(&mm->mmlist);
mm->flags = (current->mm) ? current->mm->flags
: MMF_DUMP_FILTER_DEFAULT;
- mm->core_waiters = 0;
+ mm->core_state = NULL;
mm->nr_ptes = 0;
set_mm_counter(mm, file_rss, 0);
set_mm_counter(mm, anon_rss, 0);
@@ -386,6 +415,7 @@ static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p)
if (likely(!mm_alloc_pgd(mm))) {
mm->def_flags = 0;
+ mmu_notifier_mm_init(mm);
return mm;
}
@@ -418,6 +448,7 @@ void __mmdrop(struct mm_struct *mm)
BUG_ON(mm == &init_mm);
mm_free_pgd(mm);
destroy_context(mm);
+ mmu_notifier_mm_destroy(mm);
free_mm(mm);
}
EXPORT_SYMBOL_GPL(__mmdrop);
@@ -447,7 +478,7 @@ EXPORT_SYMBOL_GPL(mmput);
/**
* get_task_mm - acquire a reference to the task's mm
*
- * Returns %NULL if the task has no mm. Checks PF_BORROWED_MM (meaning
+ * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning
* this kernel workthread has transiently adopted a user mm with use_mm,
* to do its AIO) is not set and if so returns a reference to it, after
* bumping up the use count. User must release the mm via mmput()
@@ -460,7 +491,7 @@ struct mm_struct *get_task_mm(struct task_struct *task)
task_lock(task);
mm = task->mm;
if (mm) {
- if (task->flags & PF_BORROWED_MM)
+ if (task->flags & PF_KTHREAD)
mm = NULL;
else
atomic_inc(&mm->mm_users);
@@ -629,13 +660,6 @@ static struct fs_struct *__copy_fs_struct(struct fs_struct *old)
path_get(&old->root);
fs->pwd = old->pwd;
path_get(&old->pwd);
- if (old->altroot.dentry) {
- fs->altroot = old->altroot;
- path_get(&old->altroot);
- } else {
- fs->altroot.mnt = NULL;
- fs->altroot.dentry = NULL;
- }
read_unlock(&old->lock);
}
return fs;
@@ -660,136 +684,6 @@ static int copy_fs(unsigned long clone_flags, struct task_struct *tsk)
return 0;
}
-static int count_open_files(struct fdtable *fdt)
-{
- int size = fdt->max_fds;
- int i;
-
- /* Find the last open fd */
- for (i = size/(8*sizeof(long)); i > 0; ) {
- if (fdt->open_fds->fds_bits[--i])
- break;
- }
- i = (i+1) * 8 * sizeof(long);
- return i;
-}
-
-static struct files_struct *alloc_files(void)
-{
- struct files_struct *newf;
- struct fdtable *fdt;
-
- newf = kmem_cache_alloc(files_cachep, GFP_KERNEL);
- if (!newf)
- goto out;
-
- atomic_set(&newf->count, 1);
-
- spin_lock_init(&newf->file_lock);
- newf->next_fd = 0;
- fdt = &newf->fdtab;
- fdt->max_fds = NR_OPEN_DEFAULT;
- fdt->close_on_exec = (fd_set *)&newf->close_on_exec_init;
- fdt->open_fds = (fd_set *)&newf->open_fds_init;
- fdt->fd = &newf->fd_array[0];
- INIT_RCU_HEAD(&fdt->rcu);
- fdt->next = NULL;
- rcu_assign_pointer(newf->fdt, fdt);
-out:
- return newf;
-}
-
-/*
- * Allocate a new files structure and copy contents from the
- * passed in files structure.
- * errorp will be valid only when the returned files_struct is NULL.
- */
-static struct files_struct *dup_fd(struct files_struct *oldf, int *errorp)
-{
- struct files_struct *newf;
- struct file **old_fds, **new_fds;
- int open_files, size, i;
- struct fdtable *old_fdt, *new_fdt;
-
- *errorp = -ENOMEM;
- newf = alloc_files();
- if (!newf)
- goto out;
-
- spin_lock(&oldf->file_lock);
- old_fdt = files_fdtable(oldf);
- new_fdt = files_fdtable(newf);
- open_files = count_open_files(old_fdt);
-
- /*
- * Check whether we need to allocate a larger fd array and fd set.
- * Note: we're not a clone task, so the open count won't change.
- */
- if (open_files > new_fdt->max_fds) {
- new_fdt->max_fds = 0;
- spin_unlock(&oldf->file_lock);
- spin_lock(&newf->file_lock);
- *errorp = expand_files(newf, open_files-1);
- spin_unlock(&newf->file_lock);
- if (*errorp < 0)
- goto out_release;
- new_fdt = files_fdtable(newf);
- /*
- * Reacquire the oldf lock and a pointer to its fd table
- * who knows it may have a new bigger fd table. We need
- * the latest pointer.
- */
- spin_lock(&oldf->file_lock);
- old_fdt = files_fdtable(oldf);
- }
-
- old_fds = old_fdt->fd;
- new_fds = new_fdt->fd;
-
- memcpy(new_fdt->open_fds->fds_bits,
- old_fdt->open_fds->fds_bits, open_files/8);
- memcpy(new_fdt->close_on_exec->fds_bits,
- old_fdt->close_on_exec->fds_bits, open_files/8);
-
- for (i = open_files; i != 0; i--) {
- struct file *f = *old_fds++;
- if (f) {
- get_file(f);
- } else {
- /*
- * The fd may be claimed in the fd bitmap but not yet
- * instantiated in the files array if a sibling thread
- * is partway through open(). So make sure that this
- * fd is available to the new process.
- */
- FD_CLR(open_files - i, new_fdt->open_fds);
- }
- rcu_assign_pointer(*new_fds++, f);
- }
- spin_unlock(&oldf->file_lock);
-
- /* compute the remainder to be cleared */
- size = (new_fdt->max_fds - open_files) * sizeof(struct file *);
-
- /* This is long word aligned thus could use a optimized version */
- memset(new_fds, 0, size);
-
- if (new_fdt->max_fds > open_files) {
- int left = (new_fdt->max_fds-open_files)/8;
- int start = open_files / (8 * sizeof(unsigned long));
-
- memset(&new_fdt->open_fds->fds_bits[start], 0, left);
- memset(&new_fdt->close_on_exec->fds_bits[start], 0, left);
- }
-
- return newf;
-
-out_release:
- kmem_cache_free(files_cachep, newf);
-out:
- return NULL;
-}
-
static int copy_files(unsigned long clone_flags, struct task_struct * tsk)
{
struct files_struct *oldf, *newf;
@@ -915,6 +809,7 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
sig->nvcsw = sig->nivcsw = sig->cnvcsw = sig->cnivcsw = 0;
sig->min_flt = sig->maj_flt = sig->cmin_flt = sig->cmaj_flt = 0;
sig->inblock = sig->oublock = sig->cinblock = sig->coublock = 0;
+ task_io_accounting_init(&sig->ioac);
sig->sum_sched_runtime = 0;
INIT_LIST_HEAD(&sig->cpu_timers[0]);
INIT_LIST_HEAD(&sig->cpu_timers[1]);
@@ -962,8 +857,7 @@ static void copy_flags(unsigned long clone_flags, struct task_struct *p)
new_flags &= ~PF_SUPERPRIV;
new_flags |= PF_FORKNOEXEC;
- if (!(clone_flags & CLONE_PTRACE))
- p->ptrace = 0;
+ new_flags |= PF_STARTING;
p->flags = new_flags;
clear_freeze_flag(p);
}
@@ -1004,7 +898,8 @@ static struct task_struct *copy_process(unsigned long clone_flags,
struct pt_regs *regs,
unsigned long stack_size,
int __user *child_tidptr,
- struct pid *pid)
+ struct pid *pid,
+ int trace)
{
int retval;
struct task_struct *p;
@@ -1039,7 +934,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
rt_mutex_init_task(p);
-#ifdef CONFIG_TRACE_IRQFLAGS
+#ifdef CONFIG_PROVE_LOCKING
DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled);
DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled);
#endif
@@ -1097,13 +992,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
p->last_switch_timestamp = 0;
#endif
-#ifdef CONFIG_TASK_XACCT
- p->rchar = 0; /* I/O counter: bytes read */
- p->wchar = 0; /* I/O counter: bytes written */
- p->syscr = 0; /* I/O counter: read syscalls */
- p->syscw = 0; /* I/O counter: write syscalls */
-#endif
- task_io_accounting_init(p);
+ task_io_accounting_init(&p->ioac);
acct_clear_integrals(p);
p->it_virt_expires = cputime_zero;
@@ -1210,6 +1099,12 @@ static struct task_struct *copy_process(unsigned long clone_flags,
if (clone_flags & CLONE_THREAD)
p->tgid = current->tgid;
+ if (current->nsproxy != p->nsproxy) {
+ retval = ns_cgroup_clone(p, pid);
+ if (retval)
+ goto bad_fork_free_pid;
+ }
+
p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL;
/*
* Clear TID on mm_release()?
@@ -1254,8 +1149,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
*/
p->group_leader = p;
INIT_LIST_HEAD(&p->thread_group);
- INIT_LIST_HEAD(&p->ptrace_children);
- INIT_LIST_HEAD(&p->ptrace_list);
/* Now that the task is set up, run cgroup callbacks if
* necessary. We need to run them before the task is visible
@@ -1286,7 +1179,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
p->real_parent = current->real_parent;
else
p->real_parent = current;
- p->parent = p->real_parent;
spin_lock(&current->sighand->siglock);
@@ -1327,9 +1219,8 @@ static struct task_struct *copy_process(unsigned long clone_flags,
}
if (likely(p->pid)) {
- add_parent(p);
- if (unlikely(p->ptrace & PT_PTRACED))
- __ptrace_link(p, current->parent);
+ list_add_tail(&p->sibling, &p->real_parent->children);
+ tracehook_finish_clone(p, clone_flags, trace);
if (thread_group_leader(p)) {
if (clone_flags & CLONE_NEWPID)
@@ -1414,29 +1305,13 @@ struct task_struct * __cpuinit fork_idle(int cpu)
struct pt_regs regs;
task = copy_process(CLONE_VM, 0, idle_regs(&regs), 0, NULL,
- &init_struct_pid);
+ &init_struct_pid, 0);
if (!IS_ERR(task))
init_idle(task, cpu);
return task;
}
-static int fork_traceflag(unsigned clone_flags)
-{
- if (clone_flags & CLONE_UNTRACED)
- return 0;
- else if (clone_flags & CLONE_VFORK) {
- if (current->ptrace & PT_TRACE_VFORK)
- return PTRACE_EVENT_VFORK;
- } else if ((clone_flags & CSIGNAL) != SIGCHLD) {
- if (current->ptrace & PT_TRACE_CLONE)
- return PTRACE_EVENT_CLONE;
- } else if (current->ptrace & PT_TRACE_FORK)
- return PTRACE_EVENT_FORK;
-
- return 0;
-}
-
/*
* Ok, this is the main fork-routine.
*
@@ -1471,14 +1346,14 @@ long do_fork(unsigned long clone_flags,
}
}
- if (unlikely(current->ptrace)) {
- trace = fork_traceflag (clone_flags);
- if (trace)
- clone_flags |= CLONE_PTRACE;
- }
+ /*
+ * When called from kernel_thread, don't do user tracing stuff.
+ */
+ if (likely(user_mode(regs)))
+ trace = tracehook_prepare_clone(clone_flags);
p = copy_process(clone_flags, stack_start, regs, stack_size,
- child_tidptr, NULL);
+ child_tidptr, NULL, trace);
/*
* Do this prior waking up the new thread - the thread pointer
* might get invalid after that point, if the thread exits quickly.
@@ -1496,32 +1371,35 @@ long do_fork(unsigned long clone_flags,
init_completion(&vfork);
}
- if ((p->ptrace & PT_PTRACED) || (clone_flags & CLONE_STOPPED)) {
+ tracehook_report_clone(trace, regs, clone_flags, nr, p);
+
+ /*
+ * We set PF_STARTING at creation in case tracing wants to
+ * use this to distinguish a fully live task from one that
+ * hasn't gotten to tracehook_report_clone() yet. Now we
+ * clear it and set the child going.
+ */
+ p->flags &= ~PF_STARTING;
+
+ if (unlikely(clone_flags & CLONE_STOPPED)) {
/*
* We'll start up with an immediate SIGSTOP.
*/
sigaddset(&p->pending.signal, SIGSTOP);
set_tsk_thread_flag(p, TIF_SIGPENDING);
- }
-
- if (!(clone_flags & CLONE_STOPPED))
- wake_up_new_task(p, clone_flags);
- else
__set_task_state(p, TASK_STOPPED);
-
- if (unlikely (trace)) {
- current->ptrace_message = nr;
- ptrace_notify ((trace << 8) | SIGTRAP);
+ } else {
+ wake_up_new_task(p, clone_flags);
}
+ tracehook_report_clone_complete(trace, regs,
+ clone_flags, nr, p);
+
if (clone_flags & CLONE_VFORK) {
freezer_do_not_count();
wait_for_completion(&vfork);
freezer_count();
- if (unlikely (current->ptrace & PT_TRACE_VFORK_DONE)) {
- current->ptrace_message = nr;
- ptrace_notify ((PTRACE_EVENT_VFORK_DONE << 8) | SIGTRAP);
- }
+ tracehook_report_vfork_done(p, nr);
}
} else {
nr = PTR_ERR(p);
@@ -1533,7 +1411,7 @@ long do_fork(unsigned long clone_flags,
#define ARCH_MIN_MMSTRUCT_ALIGN 0
#endif
-static void sighand_ctor(struct kmem_cache *cachep, void *data)
+static void sighand_ctor(void *data)
{
struct sighand_struct *sighand = data;
generated by cgit v1.2.3 (git 2.25.1) at 2026-05-05 09:38:53 +0000