On Wed, 2021-06-09 at 17:26 -0400, Olivier Langlois wrote: > On Wed, 2021-06-09 at 16:05 -0500, Eric W. Biederman wrote: > > > > > > So the TIF_NOTIFY_SIGNAL does get set WHILE the core dump is > > > written. > > > > Did you mean? > > > > So the TIF_NOTIFY_SIGNAL does _not_ get set WHILE the core dump is > > written. > > > > > Absolutely not. I did really mean what I have said. Bear with me > that, > I am not qualifying myself as an expert kernel dev yet so feel free > to > correct me if I say some heresy... > > io_uring is placing my task in my TCP socket wait queue because it > wants to read data from it. > > The task returns to user space and core dump with a SEGV. > > now my understanding is that the code that is waking up tasks, it is > the NIC driver interrupt handler which can occur while the core dump > is > written. > > does that make sense? > > my testing is telling me that this is exactly what happens... > > Another thing to know is that dump_interrupted() isn't only called from do_coredump(). At first, I did the mistake to think that if dump_interrupt() was returning false when called from do_coredump() all was good. It is not the case. dump_interrupted() is also called from dump_emit() which is called from several places by functions inside binfmt_elf.c So dump_interrupted() is called several times during the coredump generation.
