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-rw-r--r--kernel/fork.c185
1 files changed, 115 insertions, 70 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index a8eab86de7f1..3384eb89cb1c 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -84,7 +84,7 @@ static kmem_cache_t *task_struct_cachep;
#endif
/* SLAB cache for signal_struct structures (tsk->signal) */
-kmem_cache_t *signal_cachep;
+static kmem_cache_t *signal_cachep;
/* SLAB cache for sighand_struct structures (tsk->sighand) */
kmem_cache_t *sighand_cachep;
@@ -108,10 +108,8 @@ void free_task(struct task_struct *tsk)
}
EXPORT_SYMBOL(free_task);
-void __put_task_struct_cb(struct rcu_head *rhp)
+void __put_task_struct(struct task_struct *tsk)
{
- struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
-
WARN_ON(!(tsk->exit_state & (EXIT_DEAD | EXIT_ZOMBIE)));
WARN_ON(atomic_read(&tsk->usage));
WARN_ON(tsk == current);
@@ -126,6 +124,12 @@ void __put_task_struct_cb(struct rcu_head *rhp)
free_task(tsk);
}
+void __put_task_struct_cb(struct rcu_head *rhp)
+{
+ struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
+ __put_task_struct(tsk);
+}
+
void __init fork_init(unsigned long mempages)
{
#ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
@@ -181,6 +185,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig)
/* One for us, one for whoever does the "release_task()" (usually parent) */
atomic_set(&tsk->usage,2);
atomic_set(&tsk->fs_excl, 0);
+ tsk->btrace_seq = 0;
return tsk;
}
@@ -607,12 +612,12 @@ static struct files_struct *alloc_files(void)
atomic_set(&newf->count, 1);
spin_lock_init(&newf->file_lock);
+ newf->next_fd = 0;
fdt = &newf->fdtab;
- fdt->next_fd = 0;
fdt->max_fds = NR_OPEN_DEFAULT;
- fdt->max_fdset = __FD_SETSIZE;
- fdt->close_on_exec = &newf->close_on_exec_init;
- fdt->open_fds = &newf->open_fds_init;
+ fdt->max_fdset = EMBEDDED_FD_SET_SIZE;
+ 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->free_files = NULL;
@@ -720,7 +725,7 @@ out_release:
free_fdset (new_fdt->open_fds, new_fdt->max_fdset);
free_fd_array(new_fdt->fd, new_fdt->max_fds);
kmem_cache_free(files_cachep, newf);
- goto out;
+ return NULL;
}
static int copy_files(unsigned long clone_flags, struct task_struct * tsk)
@@ -768,8 +773,7 @@ int unshare_files(void)
struct files_struct *files = current->files;
int rc;
- if(!files)
- BUG();
+ BUG_ON(!files);
/* This can race but the race causes us to copy when we don't
need to and drop the copy */
@@ -786,14 +790,6 @@ int unshare_files(void)
EXPORT_SYMBOL(unshare_files);
-void sighand_free_cb(struct rcu_head *rhp)
-{
- struct sighand_struct *sp;
-
- sp = container_of(rhp, struct sighand_struct, rcu);
- kmem_cache_free(sighand_cachep, sp);
-}
-
static inline int copy_sighand(unsigned long clone_flags, struct task_struct * tsk)
{
struct sighand_struct *sig;
@@ -806,12 +802,17 @@ static inline int copy_sighand(unsigned long clone_flags, struct task_struct * t
rcu_assign_pointer(tsk->sighand, sig);
if (!sig)
return -ENOMEM;
- spin_lock_init(&sig->siglock);
atomic_set(&sig->count, 1);
memcpy(sig->action, current->sighand->action, sizeof(sig->action));
return 0;
}
+void __cleanup_sighand(struct sighand_struct *sighand)
+{
+ if (atomic_dec_and_test(&sighand->count))
+ kmem_cache_free(sighand_cachep, sighand);
+}
+
static inline int copy_signal(unsigned long clone_flags, struct task_struct * tsk)
{
struct signal_struct *sig;
@@ -847,7 +848,7 @@ static inline int copy_signal(unsigned long clone_flags, struct task_struct * ts
hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_REL);
sig->it_real_incr.tv64 = 0;
sig->real_timer.function = it_real_fn;
- sig->real_timer.data = tsk;
+ sig->tsk = tsk;
sig->it_virt_expires = cputime_zero;
sig->it_virt_incr = cputime_zero;
@@ -881,6 +882,22 @@ static inline int copy_signal(unsigned long clone_flags, struct task_struct * ts
return 0;
}
+void __cleanup_signal(struct signal_struct *sig)
+{
+ exit_thread_group_keys(sig);
+ kmem_cache_free(signal_cachep, sig);
+}
+
+static inline void cleanup_signal(struct task_struct *tsk)
+{
+ struct signal_struct *sig = tsk->signal;
+
+ atomic_dec(&sig->live);
+
+ if (atomic_dec_and_test(&sig->count))
+ __cleanup_signal(sig);
+}
+
static inline void copy_flags(unsigned long clone_flags, struct task_struct *p)
{
unsigned long new_flags = p->flags;
@@ -1020,6 +1037,7 @@ static task_t *copy_process(unsigned long clone_flags,
p->mempolicy = NULL;
goto bad_fork_cleanup_cpuset;
}
+ mpol_fix_fork_child_flag(p);
#endif
#ifdef CONFIG_DEBUG_MUTEXES
@@ -1060,6 +1078,15 @@ static task_t *copy_process(unsigned long clone_flags,
* Clear TID on mm_release()?
*/
p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL;
+ p->robust_list = NULL;
+#ifdef CONFIG_COMPAT
+ p->compat_robust_list = NULL;
+#endif
+ /*
+ * sigaltstack should be cleared when sharing the same VM
+ */
+ if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM)
+ p->sas_ss_sp = p->sas_ss_size = 0;
/*
* Syscall tracing should be turned off in the child regardless
@@ -1085,6 +1112,7 @@ static task_t *copy_process(unsigned long clone_flags,
* We dont wake it up yet.
*/
p->group_leader = p;
+ INIT_LIST_HEAD(&p->thread_group);
INIT_LIST_HEAD(&p->ptrace_children);
INIT_LIST_HEAD(&p->ptrace_list);
@@ -1108,16 +1136,6 @@ static task_t *copy_process(unsigned long clone_flags,
!cpu_online(task_cpu(p))))
set_task_cpu(p, smp_processor_id());
- /*
- * Check for pending SIGKILL! The new thread should not be allowed
- * to slip out of an OOM kill. (or normal SIGKILL.)
- */
- if (sigismember(&current->pending.signal, SIGKILL)) {
- write_unlock_irq(&tasklist_lock);
- retval = -EINTR;
- goto bad_fork_cleanup_namespace;
- }
-
/* CLONE_PARENT re-uses the old parent */
if (clone_flags & (CLONE_PARENT|CLONE_THREAD))
p->real_parent = current->real_parent;
@@ -1126,6 +1144,23 @@ static task_t *copy_process(unsigned long clone_flags,
p->parent = p->real_parent;
spin_lock(&current->sighand->siglock);
+
+ /*
+ * Process group and session signals need to be delivered to just the
+ * parent before the fork or both the parent and the child after the
+ * fork. Restart if a signal comes in before we add the new process to
+ * it's process group.
+ * A fatal signal pending means that current will exit, so the new
+ * thread can't slip out of an OOM kill (or normal SIGKILL).
+ */
+ recalc_sigpending();
+ if (signal_pending(current)) {
+ spin_unlock(&current->sighand->siglock);
+ write_unlock_irq(&tasklist_lock);
+ retval = -ERESTARTNOINTR;
+ goto bad_fork_cleanup_namespace;
+ }
+
if (clone_flags & CLONE_THREAD) {
/*
* Important: if an exit-all has been started then
@@ -1138,17 +1173,9 @@ static task_t *copy_process(unsigned long clone_flags,
retval = -EAGAIN;
goto bad_fork_cleanup_namespace;
}
- p->group_leader = current->group_leader;
- if (current->signal->group_stop_count > 0) {
- /*
- * There is an all-stop in progress for the group.
- * We ourselves will stop as soon as we check signals.
- * Make the new thread part of that group stop too.
- */
- current->signal->group_stop_count++;
- set_tsk_thread_flag(p, TIF_SIGPENDING);
- }
+ p->group_leader = current->group_leader;
+ list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group);
if (!cputime_eq(current->signal->it_virt_expires,
cputime_zero) ||
@@ -1171,23 +1198,25 @@ static task_t *copy_process(unsigned long clone_flags,
*/
p->ioprio = current->ioprio;
- SET_LINKS(p);
- if (unlikely(p->ptrace & PT_PTRACED))
- __ptrace_link(p, current->parent);
-
- if (thread_group_leader(p)) {
- p->signal->tty = current->signal->tty;
- p->signal->pgrp = process_group(current);
- p->signal->session = current->signal->session;
- attach_pid(p, PIDTYPE_PGID, process_group(p));
- attach_pid(p, PIDTYPE_SID, p->signal->session);
- if (p->pid)
+ if (likely(p->pid)) {
+ add_parent(p);
+ if (unlikely(p->ptrace & PT_PTRACED))
+ __ptrace_link(p, current->parent);
+
+ if (thread_group_leader(p)) {
+ p->signal->tty = current->signal->tty;
+ p->signal->pgrp = process_group(current);
+ p->signal->session = current->signal->session;
+ attach_pid(p, PIDTYPE_PGID, process_group(p));
+ attach_pid(p, PIDTYPE_SID, p->signal->session);
+
+ list_add_tail(&p->tasks, &init_task.tasks);
__get_cpu_var(process_counts)++;
+ }
+ attach_pid(p, PIDTYPE_PID, p->pid);
+ nr_threads++;
}
- attach_pid(p, PIDTYPE_TGID, p->tgid);
- attach_pid(p, PIDTYPE_PID, p->pid);
- nr_threads++;
total_forks++;
spin_unlock(&current->sighand->siglock);
write_unlock_irq(&tasklist_lock);
@@ -1202,9 +1231,9 @@ bad_fork_cleanup_mm:
if (p->mm)
mmput(p->mm);
bad_fork_cleanup_signal:
- exit_signal(p);
+ cleanup_signal(p);
bad_fork_cleanup_sighand:
- exit_sighand(p);
+ __cleanup_sighand(p->sighand);
bad_fork_cleanup_fs:
exit_fs(p); /* blocking */
bad_fork_cleanup_files:
@@ -1251,7 +1280,7 @@ task_t * __devinit fork_idle(int cpu)
if (!task)
return ERR_PTR(-ENOMEM);
init_idle(task, cpu);
- unhash_process(task);
+
return task;
}
@@ -1286,17 +1315,19 @@ long do_fork(unsigned long clone_flags,
{
struct task_struct *p;
int trace = 0;
- long pid = alloc_pidmap();
+ struct pid *pid = alloc_pid();
+ long nr;
- if (pid < 0)
+ if (!pid)
return -EAGAIN;
+ nr = pid->nr;
if (unlikely(current->ptrace)) {
trace = fork_traceflag (clone_flags);
if (trace)
clone_flags |= CLONE_PTRACE;
}
- p = copy_process(clone_flags, stack_start, regs, stack_size, parent_tidptr, child_tidptr, pid);
+ p = copy_process(clone_flags, stack_start, regs, stack_size, parent_tidptr, child_tidptr, nr);
/*
* Do this prior waking up the new thread - the thread pointer
* might get invalid after that point, if the thread exits quickly.
@@ -1323,7 +1354,7 @@ long do_fork(unsigned long clone_flags,
p->state = TASK_STOPPED;
if (unlikely (trace)) {
- current->ptrace_message = pid;
+ current->ptrace_message = nr;
ptrace_notify ((trace << 8) | SIGTRAP);
}
@@ -1333,21 +1364,31 @@ long do_fork(unsigned long clone_flags,
ptrace_notify ((PTRACE_EVENT_VFORK_DONE << 8) | SIGTRAP);
}
} else {
- free_pidmap(pid);
- pid = PTR_ERR(p);
+ free_pid(pid);
+ nr = PTR_ERR(p);
}
- return pid;
+ return nr;
}
#ifndef ARCH_MIN_MMSTRUCT_ALIGN
#define ARCH_MIN_MMSTRUCT_ALIGN 0
#endif
+static void sighand_ctor(void *data, kmem_cache_t *cachep, unsigned long flags)
+{
+ struct sighand_struct *sighand = data;
+
+ if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) ==
+ SLAB_CTOR_CONSTRUCTOR)
+ spin_lock_init(&sighand->siglock);
+}
+
void __init proc_caches_init(void)
{
sighand_cachep = kmem_cache_create("sighand_cache",
sizeof(struct sighand_struct), 0,
- SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
+ SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU,
+ sighand_ctor, NULL);
signal_cachep = kmem_cache_create("signal_cache",
sizeof(struct signal_struct), 0,
SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
@@ -1472,9 +1513,7 @@ static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp)
if ((unshare_flags & CLONE_VM) &&
(mm && atomic_read(&mm->mm_users) > 1)) {
- *new_mmp = dup_mm(current);
- if (!*new_mmp)
- return -ENOMEM;
+ return -EINVAL;
}
return 0;
@@ -1530,6 +1569,12 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
check_unshare_flags(&unshare_flags);
+ /* Return -EINVAL for all unsupported flags */
+ err = -EINVAL;
+ if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
+ CLONE_VM|CLONE_FILES|CLONE_SYSVSEM))
+ goto bad_unshare_out;
+
if ((err = unshare_thread(unshare_flags)))
goto bad_unshare_out;
if ((err = unshare_fs(unshare_flags, &new_fs)))
@@ -1563,7 +1608,7 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
if (new_sigh) {
sigh = current->sighand;
- current->sighand = new_sigh;
+ rcu_assign_pointer(current->sighand, new_sigh);
new_sigh = sigh;
}
generated by cgit v1.2.3 (git 2.0.4) at 2024-09-25 22:32:39 +0000