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-rw-r--r--kernel/extable.c2
-rw-r--r--kernel/module.c12
-rw-r--r--kernel/ptrace.c57
-rw-r--r--kernel/rcupdate.c19
4 files changed, 65 insertions, 25 deletions
diff --git a/kernel/extable.c b/kernel/extable.c
index 7501b531ceed..7fe262855317 100644
--- a/kernel/extable.c
+++ b/kernel/extable.c
@@ -40,7 +40,7 @@ const struct exception_table_entry *search_exception_tables(unsigned long addr)
return e;
}
-static int core_kernel_text(unsigned long addr)
+int core_kernel_text(unsigned long addr)
{
if (addr >= (unsigned long)_stext &&
addr <= (unsigned long)_etext)
diff --git a/kernel/module.c b/kernel/module.c
index d24deb0dbbc9..bbe04862e1b0 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -705,14 +705,14 @@ EXPORT_SYMBOL(__symbol_put);
void symbol_put_addr(void *addr)
{
- unsigned long flags;
+ struct module *modaddr;
- spin_lock_irqsave(&modlist_lock, flags);
- if (!kernel_text_address((unsigned long)addr))
- BUG();
+ if (core_kernel_text((unsigned long)addr))
+ return;
- module_put(module_text_address((unsigned long)addr));
- spin_unlock_irqrestore(&modlist_lock, flags);
+ if (!(modaddr = module_text_address((unsigned long)addr)))
+ BUG();
+ module_put(modaddr);
}
EXPORT_SYMBOL_GPL(symbol_put_addr);
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 4e0f0ec003f7..921c22ad16e4 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -148,12 +148,34 @@ int ptrace_may_attach(struct task_struct *task)
int ptrace_attach(struct task_struct *task)
{
int retval;
- task_lock(task);
+
retval = -EPERM;
if (task->pid <= 1)
- goto bad;
+ goto out;
if (task->tgid == current->tgid)
- goto bad;
+ goto out;
+
+repeat:
+ /*
+ * Nasty, nasty.
+ *
+ * We want to hold both the task-lock and the
+ * tasklist_lock for writing at the same time.
+ * But that's against the rules (tasklist_lock
+ * is taken for reading by interrupts on other
+ * cpu's that may have task_lock).
+ */
+ task_lock(task);
+ local_irq_disable();
+ if (!write_trylock(&tasklist_lock)) {
+ local_irq_enable();
+ task_unlock(task);
+ do {
+ cpu_relax();
+ } while (!write_can_lock(&tasklist_lock));
+ goto repeat;
+ }
+
/* the same process cannot be attached many times */
if (task->ptrace & PT_PTRACED)
goto bad;
@@ -166,17 +188,15 @@ int ptrace_attach(struct task_struct *task)
? PT_ATTACHED : 0);
if (capable(CAP_SYS_PTRACE))
task->ptrace |= PT_PTRACE_CAP;
- task_unlock(task);
- write_lock_irq(&tasklist_lock);
__ptrace_link(task, current);
- write_unlock_irq(&tasklist_lock);
force_sig_specific(SIGSTOP, task);
- return 0;
bad:
+ write_unlock_irq(&tasklist_lock);
task_unlock(task);
+out:
return retval;
}
@@ -417,21 +437,22 @@ int ptrace_request(struct task_struct *child, long request,
*/
int ptrace_traceme(void)
{
- int ret;
+ int ret = -EPERM;
/*
* Are we already being traced?
*/
- if (current->ptrace & PT_PTRACED)
- return -EPERM;
- ret = security_ptrace(current->parent, current);
- if (ret)
- return -EPERM;
- /*
- * Set the ptrace bit in the process ptrace flags.
- */
- current->ptrace |= PT_PTRACED;
- return 0;
+ task_lock(current);
+ if (!(current->ptrace & PT_PTRACED)) {
+ ret = security_ptrace(current->parent, current);
+ /*
+ * Set the ptrace bit in the process ptrace flags.
+ */
+ if (!ret)
+ current->ptrace |= PT_PTRACED;
+ }
+ task_unlock(current);
+ return ret;
}
/**
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index 6d32ff26f948..2058f88c7bbb 100644
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -479,12 +479,31 @@ static int __rcu_pending(struct rcu_ctrlblk *rcp, struct rcu_data *rdp)
return 0;
}
+/*
+ * Check to see if there is any immediate RCU-related work to be done
+ * by the current CPU, returning 1 if so. This function is part of the
+ * RCU implementation; it is -not- an exported member of the RCU API.
+ */
int rcu_pending(int cpu)
{
return __rcu_pending(&rcu_ctrlblk, &per_cpu(rcu_data, cpu)) ||
__rcu_pending(&rcu_bh_ctrlblk, &per_cpu(rcu_bh_data, cpu));
}
+/*
+ * Check to see if any future RCU-related work will need to be done
+ * by the current CPU, even if none need be done immediately, returning
+ * 1 if so. This function is part of the RCU implementation; it is -not-
+ * an exported member of the RCU API.
+ */
+int rcu_needs_cpu(int cpu)
+{
+ struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
+ struct rcu_data *rdp_bh = &per_cpu(rcu_bh_data, cpu);
+
+ return (!!rdp->curlist || !!rdp_bh->curlist || rcu_pending(cpu));
+}
+
void rcu_check_callbacks(int cpu, int user)
{
if (user ||