diff options
| -rw-r--r-- | kernel/ptrace.c | 39 |
1 files changed, 21 insertions, 18 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 4e0f0ec003f7..b0f8da80d7d4 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -148,12 +148,16 @@ 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; + + write_lock_irq(&tasklist_lock); + task_lock(task); + /* the same process cannot be attached many times */ if (task->ptrace & PT_PTRACED) goto bad; @@ -166,17 +170,15 @@ 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 +419,22 @@ 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; } /** |