diff options
Diffstat (limited to 'kernel/fork.c')
| -rw-r--r-- | kernel/fork.c | 147 |
1 files changed, 91 insertions, 56 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index b373322ca497..b3f7a1bb5e55 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; @@ -181,6 +181,7 @@ 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 +608,12 @@ 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; @@ -768,8 +769,7 @@ 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 +786,6 @@ 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 +798,17 @@ 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 +844,7 @@ 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 +878,22 @@ 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 +1033,7 @@ 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 @@ -1060,7 +1074,10 @@ 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 */ @@ -1091,6 +1108,7 @@ 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); @@ -1114,16 +1132,6 @@ 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(¤t->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; @@ -1132,6 +1140,23 @@ static task_t *copy_process(unsigned long clone_flags, p->parent = p->real_parent; spin_lock(¤t->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(¤t->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 @@ -1144,17 +1169,9 @@ 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) || @@ -1177,23 +1194,25 @@ 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(¤t->sighand->siglock); write_unlock_irq(&tasklist_lock); @@ -1208,9 +1227,9 @@ 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: @@ -1257,7 +1276,7 @@ task_t * __devinit fork_idle(int cpu) if (!task) return ERR_PTR(-ENOMEM); init_idle(task, cpu); - unhash_process(task); + return task; } @@ -1349,11 +1368,21 @@ long do_fork(unsigned long clone_flags, #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); @@ -1534,6 +1563,12 @@ 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))) |