a non-recoverable state

I think robust is a name that's not particularly descriptive, and wonder if we should say something like
Mutex is robust, as described in the ROBUST UMUTEXES section below

in a transient

On thread termination, the kernel walks two lists of mutexes.

Probably
The two list head addresses must be provided by a prior

singly-linked. The link to the next

the kernel
"either" implies there will be two conditions.

What about:

Robust list processing is aborted if the kernel finds a mutex with any of the following conditions:

• the UMUTEX_ROBUST flag is not set
• not owned by the current thread, except...
• the combination of flags is invalid
• read of the umutex memory faults
• the list length limit described in libthr(3) is reached

without the

For each iteration, the mutex is

Although perhaps there's no need to refer to iterating here at all, and just describe it as:

Every mutex in both lists is unlocked as if...

Perhaps: is locked using the UMTX_OP_MUTEX_LOCK operation?
I.e., because lock here refers to the operation, not a state?

Also, the kernel handles the UMUTEX_RB_NOTRECOV value of the m_owner field specially, always returning the ENOTRECOVERABLE error for lock attempts, without granting the lock.

The plurals seem awkward to me here. Does "register the list heads for the current thread's robust mutex lists" seem OK?

Or, Register the robust lists's heads for the curren thread

shared robust locked mutexes seems confusing
does "element in the list of locked robust shared mutexes" seem OK?

a pointer to

The kernel inspects

seems like something is missing here. Right now, it reads as "if the mutex ... is handled more loose," ... then what?

Maybe umutex where the m_owner field

The lock was

unlocking a robust

allows another thread

A possible... strengthen the checks

by a mapped file

makes such a shared lock object persist ...

by the Virtual

mapped, the kernel

The kernel will...

A non-zero value makes...

prematurely aborted after detecting some inconsistency, as a...

locks a given