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Diffstat (limited to 'kernel')
-rw-r--r--kernel/cgroup.c58
-rw-r--r--kernel/cpuset.c20
-rw-r--r--kernel/events/core.c2
-rw-r--r--kernel/events/uprobes.c6
-rw-r--r--kernel/irq/irqdesc.c4
-rw-r--r--kernel/printk/printk.c44
-rw-r--r--kernel/trace/trace.c2
-rw-r--r--kernel/trace/trace_uprobe.c46
-rw-r--r--kernel/workqueue.c3
9 files changed, 122 insertions, 63 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 7868fc3c0bc5..70776aec2562 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1648,10 +1648,13 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
int flags, const char *unused_dev_name,
void *data)
{
+ struct super_block *pinned_sb = NULL;
+ struct cgroup_subsys *ss;
struct cgroup_root *root;
struct cgroup_sb_opts opts;
struct dentry *dentry;
int ret;
+ int i;
bool new_sb;
/*
@@ -1677,6 +1680,27 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
goto out_unlock;
}
+ /*
+ * Destruction of cgroup root is asynchronous, so subsystems may
+ * still be dying after the previous unmount. Let's drain the
+ * dying subsystems. We just need to ensure that the ones
+ * unmounted previously finish dying and don't care about new ones
+ * starting. Testing ref liveliness is good enough.
+ */
+ for_each_subsys(ss, i) {
+ if (!(opts.subsys_mask & (1 << i)) ||
+ ss->root == &cgrp_dfl_root)
+ continue;
+
+ if (!percpu_ref_tryget_live(&ss->root->cgrp.self.refcnt)) {
+ mutex_unlock(&cgroup_mutex);
+ msleep(10);
+ ret = restart_syscall();
+ goto out_free;
+ }
+ cgroup_put(&ss->root->cgrp);
+ }
+
for_each_root(root) {
bool name_match = false;
@@ -1717,15 +1741,23 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
}
/*
- * A root's lifetime is governed by its root cgroup.
- * tryget_live failure indicate that the root is being
- * destroyed. Wait for destruction to complete so that the
- * subsystems are free. We can use wait_queue for the wait
- * but this path is super cold. Let's just sleep for a bit
- * and retry.
+ * We want to reuse @root whose lifetime is governed by its
+ * ->cgrp. Let's check whether @root is alive and keep it
+ * that way. As cgroup_kill_sb() can happen anytime, we
+ * want to block it by pinning the sb so that @root doesn't
+ * get killed before mount is complete.
+ *
+ * With the sb pinned, tryget_live can reliably indicate
+ * whether @root can be reused. If it's being killed,
+ * drain it. We can use wait_queue for the wait but this
+ * path is super cold. Let's just sleep a bit and retry.
*/
- if (!percpu_ref_tryget_live(&root->cgrp.self.refcnt)) {
+ pinned_sb = kernfs_pin_sb(root->kf_root, NULL);
+ if (IS_ERR(pinned_sb) ||
+ !percpu_ref_tryget_live(&root->cgrp.self.refcnt)) {
mutex_unlock(&cgroup_mutex);
+ if (!IS_ERR_OR_NULL(pinned_sb))
+ deactivate_super(pinned_sb);
msleep(10);
ret = restart_syscall();
goto out_free;
@@ -1770,6 +1802,16 @@ out_free:
CGROUP_SUPER_MAGIC, &new_sb);
if (IS_ERR(dentry) || !new_sb)
cgroup_put(&root->cgrp);
+
+ /*
+ * If @pinned_sb, we're reusing an existing root and holding an
+ * extra ref on its sb. Mount is complete. Put the extra ref.
+ */
+ if (pinned_sb) {
+ WARN_ON(new_sb);
+ deactivate_super(pinned_sb);
+ }
+
return dentry;
}
@@ -3328,7 +3370,7 @@ bool css_has_online_children(struct cgroup_subsys_state *css)
rcu_read_lock();
css_for_each_child(child, css) {
- if (css->flags & CSS_ONLINE) {
+ if (child->flags & CSS_ONLINE) {
ret = true;
break;
}
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index f6b33c696224..116a4164720a 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1181,7 +1181,13 @@ done:
int current_cpuset_is_being_rebound(void)
{
- return task_cs(current) == cpuset_being_rebound;
+ int ret;
+
+ rcu_read_lock();
+ ret = task_cs(current) == cpuset_being_rebound;
+ rcu_read_unlock();
+
+ return ret;
}
static int update_relax_domain_level(struct cpuset *cs, s64 val)
@@ -1617,7 +1623,17 @@ static ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
* resources, wait for the previously scheduled operations before
* proceeding, so that we don't end up keep removing tasks added
* after execution capability is restored.
+ *
+ * cpuset_hotplug_work calls back into cgroup core via
+ * cgroup_transfer_tasks() and waiting for it from a cgroupfs
+ * operation like this one can lead to a deadlock through kernfs
+ * active_ref protection. Let's break the protection. Losing the
+ * protection is okay as we check whether @cs is online after
+ * grabbing cpuset_mutex anyway. This only happens on the legacy
+ * hierarchies.
*/
+ css_get(&cs->css);
+ kernfs_break_active_protection(of->kn);
flush_work(&cpuset_hotplug_work);
mutex_lock(&cpuset_mutex);
@@ -1645,6 +1661,8 @@ static ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
free_trial_cpuset(trialcs);
out_unlock:
mutex_unlock(&cpuset_mutex);
+ kernfs_unbreak_active_protection(of->kn);
+ css_put(&cs->css);
return retval ?: nbytes;
}
diff --git a/kernel/events/core.c b/kernel/events/core.c
index a33d9a2bcbd7..b0c95f0f06fd 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2320,7 +2320,7 @@ static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
next_parent = rcu_dereference(next_ctx->parent_ctx);
/* If neither context have a parent context; they cannot be clones. */
- if (!parent && !next_parent)
+ if (!parent || !next_parent)
goto unlock;
if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index c445e392e93f..6f3254e8c137 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -846,7 +846,7 @@ static void __uprobe_unregister(struct uprobe *uprobe, struct uprobe_consumer *u
{
int err;
- if (!consumer_del(uprobe, uc)) /* WARN? */
+ if (WARN_ON(!consumer_del(uprobe, uc)))
return;
err = register_for_each_vma(uprobe, NULL);
@@ -927,7 +927,7 @@ int uprobe_apply(struct inode *inode, loff_t offset,
int ret = -ENOENT;
uprobe = find_uprobe(inode, offset);
- if (!uprobe)
+ if (WARN_ON(!uprobe))
return ret;
down_write(&uprobe->register_rwsem);
@@ -952,7 +952,7 @@ void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consume
struct uprobe *uprobe;
uprobe = find_uprobe(inode, offset);
- if (!uprobe)
+ if (WARN_ON(!uprobe))
return;
down_write(&uprobe->register_rwsem);
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 7339e42a85ab..1487a123db5c 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -455,9 +455,9 @@ EXPORT_SYMBOL_GPL(irq_alloc_hwirqs);
*/
void irq_free_hwirqs(unsigned int from, int cnt)
{
- int i;
+ int i, j;
- for (i = from; cnt > 0; i++, cnt--) {
+ for (i = from, j = cnt; j > 0; i++, j--) {
irq_set_status_flags(i, _IRQ_NOREQUEST | _IRQ_NOPROBE);
arch_teardown_hwirq(i);
}
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index ea2d5f6962ed..13e839dbca07 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1416,9 +1416,10 @@ static int have_callable_console(void)
/*
* Can we actually use the console at this time on this cpu?
*
- * Console drivers may assume that per-cpu resources have been allocated. So
- * unless they're explicitly marked as being able to cope (CON_ANYTIME) don't
- * call them until this CPU is officially up.
+ * Console drivers may assume that per-cpu resources have
+ * been allocated. So unless they're explicitly marked as
+ * being able to cope (CON_ANYTIME) don't call them until
+ * this CPU is officially up.
*/
static inline int can_use_console(unsigned int cpu)
{
@@ -1431,10 +1432,8 @@ static inline int can_use_console(unsigned int cpu)
* console_lock held, and 'console_locked' set) if it
* is successful, false otherwise.
*/
-static int console_trylock_for_printk(void)
+static int console_trylock_for_printk(unsigned int cpu)
{
- unsigned int cpu = smp_processor_id();
-
if (!console_trylock())
return 0;
/*
@@ -1609,8 +1608,7 @@ asmlinkage int vprintk_emit(int facility, int level,
*/
if (!oops_in_progress && !lockdep_recursing(current)) {
recursion_bug = 1;
- local_irq_restore(flags);
- return 0;
+ goto out_restore_irqs;
}
zap_locks();
}
@@ -1718,27 +1716,21 @@ asmlinkage int vprintk_emit(int facility, int level,
logbuf_cpu = UINT_MAX;
raw_spin_unlock(&logbuf_lock);
- lockdep_on();
- local_irq_restore(flags);
/* If called from the scheduler, we can not call up(). */
- if (in_sched)
- return printed_len;
-
- /*
- * Disable preemption to avoid being preempted while holding
- * console_sem which would prevent anyone from printing to console
- */
- preempt_disable();
- /*
- * Try to acquire and then immediately release the console semaphore.
- * The release will print out buffers and wake up /dev/kmsg and syslog()
- * users.
- */
- if (console_trylock_for_printk())
- console_unlock();
- preempt_enable();
+ if (!in_sched) {
+ /*
+ * Try to acquire and then immediately release the console
+ * semaphore. The release will print out buffers and wake up
+ * /dev/kmsg and syslog() users.
+ */
+ if (console_trylock_for_printk(this_cpu))
+ console_unlock();
+ }
+ lockdep_on();
+out_restore_irqs:
+ local_irq_restore(flags);
return printed_len;
}
EXPORT_SYMBOL(vprintk_emit);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 384ede311717..f243444a3772 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1396,7 +1396,6 @@ void tracing_start(void)
arch_spin_unlock(&global_trace.max_lock);
- ftrace_start();
out:
raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
}
@@ -1443,7 +1442,6 @@ void tracing_stop(void)
struct ring_buffer *buffer;
unsigned long flags;
- ftrace_stop();
raw_spin_lock_irqsave(&global_trace.start_lock, flags);
if (global_trace.stop_count++)
goto out;
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 04fdb5de823c..3c9b97e6b1f4 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -893,6 +893,9 @@ probe_event_enable(struct trace_uprobe *tu, struct ftrace_event_file *file,
int ret;
if (file) {
+ if (tu->tp.flags & TP_FLAG_PROFILE)
+ return -EINTR;
+
link = kmalloc(sizeof(*link), GFP_KERNEL);
if (!link)
return -ENOMEM;
@@ -901,29 +904,40 @@ probe_event_enable(struct trace_uprobe *tu, struct ftrace_event_file *file,
list_add_tail_rcu(&link->list, &tu->tp.files);
tu->tp.flags |= TP_FLAG_TRACE;
- } else
- tu->tp.flags |= TP_FLAG_PROFILE;
+ } else {
+ if (tu->tp.flags & TP_FLAG_TRACE)
+ return -EINTR;
- ret = uprobe_buffer_enable();
- if (ret < 0)
- return ret;
+ tu->tp.flags |= TP_FLAG_PROFILE;
+ }
WARN_ON(!uprobe_filter_is_empty(&tu->filter));
if (enabled)
return 0;
+ ret = uprobe_buffer_enable();
+ if (ret)
+ goto err_flags;
+
tu->consumer.filter = filter;
ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
- if (ret) {
- if (file) {
- list_del(&link->list);
- kfree(link);
- tu->tp.flags &= ~TP_FLAG_TRACE;
- } else
- tu->tp.flags &= ~TP_FLAG_PROFILE;
- }
+ if (ret)
+ goto err_buffer;
+ return 0;
+
+ err_buffer:
+ uprobe_buffer_disable();
+
+ err_flags:
+ if (file) {
+ list_del(&link->list);
+ kfree(link);
+ tu->tp.flags &= ~TP_FLAG_TRACE;
+ } else {
+ tu->tp.flags &= ~TP_FLAG_PROFILE;
+ }
return ret;
}
@@ -1201,12 +1215,6 @@ static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
current->utask->vaddr = (unsigned long) &udd;
-#ifdef CONFIG_PERF_EVENTS
- if ((tu->tp.flags & TP_FLAG_TRACE) == 0 &&
- !uprobe_perf_filter(&tu->consumer, 0, current->mm))
- return UPROBE_HANDLER_REMOVE;
-#endif
-
if (WARN_ON_ONCE(!uprobe_cpu_buffer))
return 0;
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 6203d2900877..35974ac69600 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -3284,6 +3284,7 @@ int workqueue_sysfs_register(struct workqueue_struct *wq)
}
}
+ dev_set_uevent_suppress(&wq_dev->dev, false);
kobject_uevent(&wq_dev->dev.kobj, KOBJ_ADD);
return 0;
}
@@ -4879,7 +4880,7 @@ static void __init wq_numa_init(void)
BUG_ON(!tbl);
for_each_node(node)
- BUG_ON(!alloc_cpumask_var_node(&tbl[node], GFP_KERNEL,
+ BUG_ON(!zalloc_cpumask_var_node(&tbl[node], GFP_KERNEL,
node_online(node) ? node : NUMA_NO_NODE));
for_each_possible_cpu(cpu) {
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-24 12:05:36 +0300