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>
To avoid unnecessary warnings and errors in the future I'd like to
propose building all cgo related sources with `-Wall -Werror`. This
commit fixes some warnings which came up in `shm_lock.c`, too.
Signed-off-by: Sascha Grunert <sgrunert@suse.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>
When we're renumbering locks, we're destroying all existing
allocations anyways, so destroying the old lock struct is not a
particularly big deal. Existing long-lived libpod instances will
continue to use the old locks, but that will be solved in a
followon.
Also, solve an issue with returning error values in the C code.
There were a few places where we return ERRNO where it was not
set, so make them return actual error codes).
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>
Move SHM specific code into a subpackage. Within the main locks
package, move the manager to be linux-only and add a non-Linux
unsupported build file.
Signed-off-by: Matthew Heon <matthew.heon@gmail.com>
Matt Heon