yoush.homelinux.org

Yes it is. Go read this.

P.S.
My own – yet very limited – experience of running android port on a custom board, only proves that. Android crashes and burns on almost any possible error. Audio driver failed to initialize? Crash. USB keyboard connected? Crash. It behaves even worse than windows 10 years ago.

Shame on google.

Our today’s hero is company named Port, with their can4linux drivers.

These people demonstrate wonderful knowledge on how to do mutual-exclusion in kernel. Here is an example:

    if(0 == atomic_read(&Can_isopen[minor])) {
        /* first time called, initialize hardware and global data */
        ...
    }
    ... /* many more code, without any locks held */
    atomic_inc(&Can_isopen[minor]);

Looks like they are sure that using atomic here will help them to catch first call reliably.

One more example:

    spin_lock(&waitflag_lock);
    for(i = 0; i < CAN_MAX_OPEN; i++) {
        if(CanWaitFlag[minor][i] == 0) break;
    }
    spin_unlock(&waitflag_lock);

And now they think that i is a reliable index of zero array element.

Both examples taken from their open() routine.

There are numerous other issues in the code - races, improper use of kernel infrastructure, etc. A very good example of out-of-community, no-review development.

Anyway, they are still in business, and do offer all that to their customers. Let's wish them good luck .