diff options
| -rw-r--r-- | fs/exec.c | 2 | ||||
| -rw-r--r-- | include/linux/kthread.h | 2 | ||||
| -rw-r--r-- | kernel/fork.c | 4 | ||||
| -rw-r--r-- | kernel/kthread.c | 31 | ||||
| -rw-r--r-- | kernel/sched/core.c | 16 |
5 files changed, 29 insertions, 26 deletions
diff --git a/fs/exec.c b/fs/exec.c index 537d92c41105..59cac7c18178 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1307,6 +1307,8 @@ int begin_new_exec(struct linux_binprm * bprm) */ force_uaccess_begin(); + if (me->flags & PF_KTHREAD) + free_kthread_struct(me); me->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD | PF_NOFREEZE | PF_NO_SETAFFINITY); flush_thread(); diff --git a/include/linux/kthread.h b/include/linux/kthread.h index d86a7e3b9a52..4f3433afb54b 100644 --- a/include/linux/kthread.h +++ b/include/linux/kthread.h @@ -33,7 +33,7 @@ struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data), unsigned int cpu, const char *namefmt); -void set_kthread_struct(struct task_struct *p); +bool set_kthread_struct(struct task_struct *p); void kthread_set_per_cpu(struct task_struct *k, int cpu); bool kthread_is_per_cpu(struct task_struct *k); diff --git a/kernel/fork.c b/kernel/fork.c index 3244cc56b697..04fa3e5d97af 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2118,6 +2118,10 @@ static __latent_entropy struct task_struct *copy_process( p->io_context = NULL; audit_set_context(p, NULL); cgroup_fork(p); + if (p->flags & PF_KTHREAD) { + if (!set_kthread_struct(p)) + goto bad_fork_cleanup_threadgroup_lock; + } #ifdef CONFIG_NUMA p->mempolicy = mpol_dup(p->mempolicy); if (IS_ERR(p->mempolicy)) { diff --git a/kernel/kthread.c b/kernel/kthread.c index 4388d6694a7f..8e5f44bed027 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -93,20 +93,27 @@ static inline struct kthread *__to_kthread(struct task_struct *p) return kthread; } -void set_kthread_struct(struct task_struct *p) +bool set_kthread_struct(struct task_struct *p) { struct kthread *kthread; - if (__to_kthread(p)) - return; + if (WARN_ON_ONCE(to_kthread(p))) + return false; kthread = kzalloc(sizeof(*kthread), GFP_KERNEL); + if (!kthread) + return false; + + init_completion(&kthread->exited); + init_completion(&kthread->parked); + p->vfork_done = &kthread->exited; + /* * We abuse ->set_child_tid to avoid the new member and because it - * can't be wrongly copied by copy_process(). We also rely on fact - * that the caller can't exec, so PF_KTHREAD can't be cleared. + * can't be wrongly copied by copy_process(). */ p->set_child_tid = (__force void __user *)kthread; + return true; } void free_kthread_struct(struct task_struct *k) @@ -114,13 +121,13 @@ void free_kthread_struct(struct task_struct *k) struct kthread *kthread; /* - * Can be NULL if this kthread was created by kernel_thread() - * or if kmalloc() in kthread() failed. + * Can be NULL if kmalloc() in set_kthread_struct() failed. */ kthread = to_kthread(k); #ifdef CONFIG_BLK_CGROUP WARN_ON_ONCE(kthread && kthread->blkcg_css); #endif + k->set_child_tid = (__force void __user *)NULL; kfree(kthread); } @@ -315,7 +322,6 @@ static int kthread(void *_create) struct kthread *self; int ret; - set_kthread_struct(current); self = to_kthread(current); /* If user was SIGKILLed, I release the structure. */ @@ -325,17 +331,8 @@ static int kthread(void *_create) kthread_exit(-EINTR); } - if (!self) { - create->result = ERR_PTR(-ENOMEM); - complete(done); - kthread_exit(-ENOMEM); - } - self->threadfn = threadfn; self->data = data; - init_completion(&self->exited); - init_completion(&self->parked); - current->vfork_done = &self->exited; /* * The new thread inherited kthreadd's priority and CPU mask. Reset diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 3c9b0fda64ac..0404a8c572a1 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -8599,14 +8599,6 @@ void __init init_idle(struct task_struct *idle, int cpu) __sched_fork(0, idle); - /* - * The idle task doesn't need the kthread struct to function, but it - * is dressed up as a per-CPU kthread and thus needs to play the part - * if we want to avoid special-casing it in code that deals with per-CPU - * kthreads. - */ - set_kthread_struct(idle); - raw_spin_lock_irqsave(&idle->pi_lock, flags); raw_spin_rq_lock(rq); @@ -9428,6 +9420,14 @@ void __init sched_init(void) enter_lazy_tlb(&init_mm, current); /* + * The idle task doesn't need the kthread struct to function, but it + * is dressed up as a per-CPU kthread and thus needs to play the part + * if we want to avoid special-casing it in code that deals with per-CPU + * kthreads. + */ + WARN_ON(set_kthread_struct(current)); + + /* * Make us the idle thread. Technically, schedule() should not be * called from this thread, however somewhere below it might be, * but because we are the idle thread, we just pick up running again |