On 3/3/20 11:34 AM, Bernd Edlinger wrote:
On 3/3/20 9:58 AM, Christian Brauner wrote:
So one issue I see with having to reacquire the cred_guard_mutex might be that this would allow tasks holding the cred_guard_mutex to block a killed exec'ing task from exiting, right?
Yes maybe, but I think it will not be worse than it is now. Since the second time the mutex is acquired it is done with mutex_lock_killable, so at least kill -9 should get it terminated.
static void free_bprm(struct linux_binprm *bprm) { free_arg_pages(bprm); if (bprm->cred) {
if (!bprm->called_flush_old_exec)mutex_lock(¤t->signal->cred_guard_mutex);current->signal->cred_locked_for_ptrace = false;
Hmm, cough... actually when the mutex_lock_killable fails, due to kill -9, in flush_old_exec free_bprm locks the same mutex, this time unkillable, but I should better do mutex_lock_killable here, and if that fails, I can leave cred_locked_for_ptrace, it shouldn't matter, since this is a fatal signal anyway, right?
Bernd.