To debug a deadlock, we really want to know what lock is actually
locked, so we can figure out what is using that lock. This PR
adds support for this, using trylock to check if every lock on
the system is free or in use. Will really need to be run a few
times in quick succession to verify that it's not a transient
lock and it's actually stuck, but that's not really a big deal.
Signed-off-by: Matt Heon <mheon@redhat.com>
This is a nice quality-of-life change that should help to debug
situations where someone runs out of locks (usually when a bunch
of unused volumes accumulate).
Signed-off-by: Matt Heon <mheon@redhat.com>
After a reboot, when we refresh Podman's state, we retrieved the
lock from the fresh SHM instance, but we did not mark it as
allocated to prevent it being handed out to other containers and
pods.
Provide a method for marking locks as in-use, and use it when we
refresh Podman state after a reboot.
Fixes#2900
Signed-off-by: Matthew Heon <matthew.heon@pm.me>
The original intent behind the requirement was to ensure that, if
two SHM lock structs were open at the same time, we should not
make such a runtime available to the user, and should clean it up
instead.
It turns out that we don't even need to open a second SHM lock
struct - if we get an error mapping the first one due to a lock
count mismatch, we can just delete it, and it cleans itself up
when it errors. So there's no reason not to return a valid
runtime.
Signed-off-by: Matthew Heon <matthew.heon@pm.me>
Renumber is a way of renumbering container locks after the number
of locks available has changed.
For now, renumber only works with containers.
Signed-off-by: Matthew Heon <matthew.heon@pm.me>
Matt Heon
Matthew Heon
Matthew Heon