On Mon, 2022-08-22 at 17:16 -0400, Olivier Langlois wrote: > > What is stopping the task calling do_coredump() to be interrupted and > call task_work_add() from the interrupt context? > > This is precisely what I was experiencing last summer when I did work > on this issue. > > My understanding of how async I/O works with io_uring is that the > task > is added to a wait queue without being put to sleep and when the > io_uring callback is called from the interrupt context, > task_work_add() > is called so that the next time io_uring syscall is invoked, pending > work is processed to complete the I/O. > > So if: > > 1. io_uring request is initiated AND the task is in a wait queue > 2. do_coredump() is called before the I/O is completed > > IMHO, this is how you end up having task_work_add() called while the > coredump is generated. > I forgot to add that I have experienced the issue with TCP/IP I/O. I suspect that with a TCP socket, the race condition window is much larger than if it was disk I/O and this might make it easier to reproduce the issue this way...
