diff options
| -rw-r--r-- | fs/exec.c | 39 |
1 files changed, 26 insertions, 13 deletions
diff --git a/fs/exec.c b/fs/exec.c index c3f34791f2f0..ff74b9a74d34 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1194,6 +1194,23 @@ no_thread_group: flush_itimer_signals(); #endif + BUG_ON(!thread_group_leader(tsk)); + return 0; + +killed: + /* protects against exit_notify() and __exit_signal() */ + read_lock(&tasklist_lock); + sig->group_exit_task = NULL; + sig->notify_count = 0; + read_unlock(&tasklist_lock); + return -EAGAIN; +} + + +static int unshare_sighand(struct task_struct *me) +{ + struct sighand_struct *oldsighand = me->sighand; + if (refcount_read(&oldsighand->count) != 1) { struct sighand_struct *newsighand; /* @@ -1210,23 +1227,13 @@ no_thread_group: write_lock_irq(&tasklist_lock); spin_lock(&oldsighand->siglock); - rcu_assign_pointer(tsk->sighand, newsighand); + rcu_assign_pointer(me->sighand, newsighand); spin_unlock(&oldsighand->siglock); write_unlock_irq(&tasklist_lock); __cleanup_sighand(oldsighand); } - - BUG_ON(!thread_group_leader(tsk)); return 0; - -killed: - /* protects against exit_notify() and __exit_signal() */ - read_lock(&tasklist_lock); - sig->group_exit_task = NULL; - sig->notify_count = 0; - read_unlock(&tasklist_lock); - return -EAGAIN; } char *__get_task_comm(char *buf, size_t buf_size, struct task_struct *tsk) @@ -1264,14 +1271,20 @@ int flush_old_exec(struct linux_binprm * bprm) int retval; /* - * Make sure we have a private signal table and that - * we are unassociated from the previous thread group. + * Make this the only thread in the thread group. */ retval = de_thread(me); if (retval) goto out; /* + * Make the signal table private. + */ + retval = unshare_sighand(me); + if (retval) + goto out; + + /* * Must be called _before_ exec_mmap() as bprm->mm is * not visibile until then. This also enables the update * to be lockless. |