Macs crash after 49 days of uptime? ↦

Software developer Photon, whose product requires running a bunch of Macs to connect to iMessage, discovered a pretty major bug:

Every Mac has a hidden expiration date. After exactly 49 days, 17 hours, 2 minutes, and 47 seconds of continuous uptime, a 32-bit unsigned integer overflow in Apple’s XNU kernel freezes the internal TCP timestamp clock… ICMP (ping) keeps working. Everything else dies. The only fix most people know is a reboot.

The whole story is wild (albeit technical). Photon says they’re working on a fix, but really, this is something Apple should be working on.

As someone who keeps a Mac mini running in my closet, I guarantee you that I have been affected by this bug. But who remembers that it’s been 50 days since the last time your Mac server became entirely unresponsive other than pings? Unless I’m traveling, I just shrug, reboot the Mac, and go on with my life. Not great.

Update: I’ve heard from some people who report very long uptimes on Mac servers running older versions of macOS. I guess the bigger question is, what OS versions does this actually impact? Tough thing to test, given that the bug appears only after 49+ days.

Go to the linked site.

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