Re: stress-ng process termination issue

[Samuel Thibault <sthibault@debian.org>]

Hello,

Michael Kelly, le mer. 13 août 2025 22:14:15 +0100, a ecrit:
> The message header is modified within gnumach by the 'slow_send:' case
> within mach_msg_trap when ipc_mqueue_send() fails (presumed to be
> MACH_SEND_INTERRUPTED) to deliver the message.

I wouldn't be that much surprised that this is expected. At least, the
kernel seems to be coherently using ipc_kmsg_copyout_pseudo on
ipc_mqueue_send failure, so it is assuming it can indeed overwrite the
message.

> I can solve my test case by 'correcting' the message header within the
> MACH_SEND_INTERRUPTED case of _hurd_intr_rpc_mach_msg(). There are other
> places in this code that realise that the header is modified by the system
> call and make a correction to it before attempting to resend the message.

Yes, that does look reasonable. I'm not completely surprised that this
didn't get notice, since this is a rare condition.

Samuel