Re: [PATCHv2] exec: Fix a deadlock in ptrace

On 03/01, Bernd Edlinger wrote:

This fixes a deadlock in the tracer when tracing a multi-threaded application that calls execve while more than one thread are running.

Heh. Yes, known problem. See my attempt to fix it: https://lore.kernel.org/lkml/20170213141452.GA30203@redhat.com/

@@ -1224,7 +1224,7 @@ struct mm_struct *mm_access(struct task_struct *task, unsigned int mode) struct mm_struct *mm; int err;

• err = mutex_lock_killable(&task->signal->cred_guard_mutex);

• err = mutex_lock_killable(&task->signal->cred_change_mutex);

So if I understand correctly your patch doesn't fix other problems with debugger waiting for cred_guard_mutex.

I too do not think this can justify the new mutex in signal_struct...

Oleg.