diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/extable.c | 2 | ||||
| -rw-r--r-- | kernel/module.c | 12 | ||||
| -rw-r--r-- | kernel/ptrace.c | 57 | ||||
| -rw-r--r-- | kernel/rcupdate.c | 19 |
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 || |