On 18/01/2026 03:46, Damien Zammit wrote:
There are two known remaining issues with this patchset:
1. There is a problem with the recent changes regarding
_Xmach_port_set_ktype -> ipc_kobject_set that causes a hang
only on SMP kernels, which can be temporarily worked around by
reverting commit:
fdfca0e8 "Add mach_port_set_ktype RPC to set ktype of a user port"
but we really ought to dig into it and fix this.
This seems to be a case of trying to acquire a lock that is already
held. The function mach_port_set_ktype() in mach_port.c acquires the
ip_lock on the 'port' indirectly via ipc_object_translate(). The call to
ipc_kobject_set then tries to also acquire the lock already held. As a
workaround proof I added a ipc_kobject_set_unlocked() that does the same
as ipc_kobject_set() but without the lock/unlock. This alteration
allowed the i386/smp to boot to console login.
Which of these methods is the best way of fixing this properly?
1) Drop the port lock before the call to ipc_kobject_set() in some safe way.
2) As above with a version of ipc_kobject_set() that requires the port
to be already locked.
3) Something else.....
Mike.
