linux

iv/linux

History

Johannes Berg d6b399a0e0 um: time-travel/signals: fix ndelay() in interrupt

We should be able to ndelay() from any context, even from an
interrupt context! However, this is broken (not functionally,
but locking-wise) in time-travel because we'll get into the
time-travel code and enable interrupts to handle messages on
other time-travel aware subsystems (only virtio for now).

Luckily, I've already reworked the time-travel aware signal
(interrupt) delivery for suspend/resume to have a time travel
handler, which runs directly in the context of the signal and
not from the Linux interrupt.

In order to fix this time-travel issue then, we need to do a
few things:

 1) rework the signal handling code to call time-travel handlers
    (only) if interrupts are disabled but signals aren't blocked,
    instead of marking it only pending there. This is needed to
    not deadlock other communication.
 2) rework time-travel to not enable interrupts while it's
    waiting for a message;
 3) rework time-travel to not (just) disable interrupts but
    rather block signals at a lower level while it needs them
    disabled for communicating with the controller.

Finally, since now we can actually spend even virtual time
in interrupts-disabled sections, the delay warning when we
deliver a time-travel delayed interrupt is no longer valid,
things can (and should) now get delayed.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

2021-06-17 21:44:52 +02:00

skas

um: separate child and parent errors in clone stub

2021-02-12 21:34:33 +01:00

arch.h

um: Add SPDX headers for files in arch/um/include

2019-09-15 21:37:17 +02:00

as-layout.h

um: remove process stub VMA

2021-02-12 21:37:38 +01:00

common-offsets.h

um: rework userspace stubs to not hard-code stub location