runtime: total allocation stats are managed in a `uintptr` which can quickly wrap around on 32-bit architectures [1.18 backport]

[gopherbot]

@mknyszek requested issue #52680 to be considered for backport to the next 1.18 minor release.

@gopherbot Please open backport issues for Go 1.17 and Go 1.18.

[mknyszek]

Basically, on 32-bit platforms, allocation stats can end up completely wrong. I'm surprised this flew under the radar for so long. There's no workaround.

[dr2chase]

Ahoy, can you do the backport CLs here? (for this and 1.17)
It may require a little cleanup work, I tried and had merge errors.
See https://github.com/golang/go/wiki/MinorReleases

[mknyszek]

Thanks for trying David. Yeah, it's not going to be that easy because a bunch of things moved. I suspect 1.17 and 1.18 can use the same fix, but I need to basically create a separate CL for them. It'll be very similar to what landed for 1.19, but not quite the same.

[dr2chase]

Also not allowed to mail the cherry-pick if I do it by hand, oh well.
Some other time.

[toothrot]

Just checking in. The next minor release is coming up soon, and this issue has already been bumped once. Is there any new progress?

[hallgren]

We bump into this issue today where the value of MemStats.Alloc was a really high value. The reason as we understands it is that totalAlloc has rotated but not the totalFree in the updatememstats() function.

memstats.alloc = totalAlloc - totalFree