diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/fork.c | 60 | ||||
| -rw-r--r-- | kernel/hung_task.c | 11 | ||||
| -rw-r--r-- | kernel/irq/manage.c | 44 | ||||
| -rw-r--r-- | kernel/kprobes.c | 12 | ||||
| -rw-r--r-- | kernel/printk.c | 6 |
5 files changed, 97 insertions, 36 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index e2cd3e2..26a7a67 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -668,6 +668,38 @@ struct mm_struct *mm_access(struct task_struct *task, unsigned int mode) return mm; } +static void complete_vfork_done(struct task_struct *tsk) +{ + struct completion *vfork; + + task_lock(tsk); + vfork = tsk->vfork_done; + if (likely(vfork)) { + tsk->vfork_done = NULL; + complete(vfork); + } + task_unlock(tsk); +} + +static int wait_for_vfork_done(struct task_struct *child, + struct completion *vfork) +{ + int killed; + + freezer_do_not_count(); + killed = wait_for_completion_killable(vfork); + freezer_count(); + + if (killed) { + task_lock(child); + child->vfork_done = NULL; + task_unlock(child); + } + + put_task_struct(child); + return killed; +} + /* Please note the differences between mmput and mm_release. * mmput is called whenever we stop holding onto a mm_struct, * error success whatever. @@ -683,8 +715,6 @@ struct mm_struct *mm_access(struct task_struct *task, unsigned int mode) */ void mm_release(struct task_struct *tsk, struct mm_struct *mm) { - struct completion *vfork_done = tsk->vfork_done; - /* Get rid of any futexes when releasing the mm */ #ifdef CONFIG_FUTEX if (unlikely(tsk->robust_list)) { @@ -704,17 +734,15 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm) /* Get rid of any cached register state */ deactivate_mm(tsk, mm); - /* notify parent sleeping on vfork() */ - if (vfork_done) { - tsk->vfork_done = NULL; - complete(vfork_done); - } + if (tsk->vfork_done) + complete_vfork_done(tsk); /* * 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 otherwise. Userland only wants this done for a sys_exit. + * trouble, say, a killed vfork parent shouldn't touch this mm. + * Userland only wants this done for a sys_exit. */ if (tsk->clear_child_tid) { if (!(tsk->flags & PF_SIGNALED) && @@ -1018,7 +1046,6 @@ static void copy_flags(unsigned long clone_flags, struct task_struct *p) new_flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER); new_flags |= PF_FORKNOEXEC; - new_flags |= PF_STARTING; p->flags = new_flags; } @@ -1548,16 +1575,9 @@ long do_fork(unsigned long clone_flags, if (clone_flags & CLONE_VFORK) { p->vfork_done = &vfork; init_completion(&vfork); + get_task_struct(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 finished SIGSTOP raising yet. Now we clear it - * and set the child going. - */ - p->flags &= ~PF_STARTING; - wake_up_new_task(p); /* forking complete and child started to run, tell ptracer */ @@ -1565,10 +1585,8 @@ long do_fork(unsigned long clone_flags, ptrace_event(trace, nr); if (clone_flags & CLONE_VFORK) { - freezer_do_not_count(); - wait_for_completion(&vfork); - freezer_count(); - ptrace_event(PTRACE_EVENT_VFORK_DONE, nr); + if (!wait_for_vfork_done(p, &vfork)) + ptrace_event(PTRACE_EVENT_VFORK_DONE, nr); } } else { nr = PTR_ERR(p); diff --git a/kernel/hung_task.c b/kernel/hung_task.c index 2e48ec0..c21449f 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -119,15 +119,20 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout) * For preemptible RCU it is sufficient to call rcu_read_unlock in order * to exit the grace period. For classic RCU, a reschedule is required. */ -static void rcu_lock_break(struct task_struct *g, struct task_struct *t) +static bool rcu_lock_break(struct task_struct *g, struct task_struct *t) { + bool can_cont; + get_task_struct(g); get_task_struct(t); rcu_read_unlock(); cond_resched(); rcu_read_lock(); + can_cont = pid_alive(g) && pid_alive(t); put_task_struct(t); put_task_struct(g); + + return can_cont; } /* @@ -154,9 +159,7 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout) goto unlock; if (!--batch_count) { batch_count = HUNG_TASK_BATCHING; - rcu_lock_break(g, t); - /* Exit if t or g was unhashed during refresh. */ - if (t->state == TASK_DEAD || g->state == TASK_DEAD) + if (!rcu_lock_break(g, t)) goto unlock; } /* use "==" to skip the TASK_KILLABLE tasks waiting on NFS */ diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 32313c0..0f0d470 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -985,6 +985,11 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) /* add new interrupt at end of irq queue */ do { + /* + * Or all existing action->thread_mask bits, + * so we can find the next zero bit for this + * new action. + */ thread_mask |= old->thread_mask; old_ptr = &old->next; old = *old_ptr; @@ -993,14 +998,41 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) } /* - * Setup the thread mask for this irqaction. Unlikely to have - * 32 resp 64 irqs sharing one line, but who knows. + * Setup the thread mask for this irqaction for ONESHOT. For + * !ONESHOT irqs the thread mask is 0 so we can avoid a + * conditional in irq_wake_thread(). */ - if (new->flags & IRQF_ONESHOT && thread_mask == ~0UL) { - ret = -EBUSY; - goto out_mask; + if (new->flags & IRQF_ONESHOT) { + /* + * Unlikely to have 32 resp 64 irqs sharing one line, + * but who knows. + */ + if (thread_mask == ~0UL) { + ret = -EBUSY; + goto out_mask; + } + /* + * The thread_mask for the action is or'ed to + * desc->thread_active to indicate that the + * IRQF_ONESHOT thread handler has been woken, but not + * yet finished. The bit is cleared when a thread + * completes. When all threads of a shared interrupt + * line have completed desc->threads_active becomes + * zero and the interrupt line is unmasked. See + * handle.c:irq_wake_thread() for further information. + * + * If no thread is woken by primary (hard irq context) + * interrupt handlers, then desc->threads_active is + * also checked for zero to unmask the irq line in the + * affected hard irq flow handlers + * (handle_[fasteoi|level]_irq). + * + * The new action gets the first zero bit of + * thread_mask assigned. See the loop above which or's + * all existing action->thread_mask bits. + */ + new->thread_mask = 1 << ffz(thread_mask); } - new->thread_mask = 1 << ffz(thread_mask); if (!shared) { init_waitqueue_head(&desc->wait_for_threads); diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 9788c0e..c62b854 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1334,8 +1334,10 @@ int __kprobes register_kprobe(struct kprobe *p) if (!kernel_text_address((unsigned long) p->addr) || in_kprobes_functions((unsigned long) p->addr) || ftrace_text_reserved(p->addr, p->addr) || - jump_label_text_reserved(p->addr, p->addr)) - goto fail_with_jump_label; + jump_label_text_reserved(p->addr, p->addr)) { + ret = -EINVAL; + goto cannot_probe; + } /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */ p->flags &= KPROBE_FLAG_DISABLED; @@ -1352,7 +1354,7 @@ int __kprobes register_kprobe(struct kprobe *p) * its code to prohibit unexpected unloading. */ if (unlikely(!try_module_get(probed_mod))) - goto fail_with_jump_label; + goto cannot_probe; /* * If the module freed .init.text, we couldn't insert @@ -1361,7 +1363,7 @@ int __kprobes register_kprobe(struct kprobe *p) if (within_module_init((unsigned long)p->addr, probed_mod) && probed_mod->state != MODULE_STATE_COMING) { module_put(probed_mod); - goto fail_with_jump_label; + goto cannot_probe; } /* ret will be updated by following code */ } @@ -1409,7 +1411,7 @@ out: return ret; -fail_with_jump_label: +cannot_probe: preempt_enable(); jump_label_unlock(); return ret; diff --git a/kernel/printk.c b/kernel/printk.c index cb8a6bd..0b3ea2c 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -707,6 +707,9 @@ static bool printk_time = 0; #endif module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); +static bool always_kmsg_dump; +module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR); + /* Check if we have any console registered that can be called early in boot. */ static int have_callable_console(void) { @@ -1737,6 +1740,9 @@ void kmsg_dump(enum kmsg_dump_reason reason) unsigned long l1, l2; unsigned long flags; + if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump) + return; + /* Theoretically, the log could move on after we do this, but there's not a lot we can do about that. The new messages will overwrite the start of what we dump. */ |
