4 ms·

I guess we know now that from the 3000000 files or what it was they boasted about, not a lot of them are some sort of unit test..

egeozcan 9y ago
How can you test against an unknown bug?
- maltalex 9y ago
  > How can you test against an unknown bug? The point of testing is to make the unknown bugs, known.
  - naasking 9y ago
    The point of testing is actually to ensure certain classes of known bugs aren't present. You can't test for bugs of which you have no knowledge.
    - deleted 9y ago
      [deleted]
    - IncRnd 9y ago
      In this case, however, an OS should have some sort of test in place that process and user isolation is being enforced. That is certainly a known situation that can be tested. It is also a selling point of the OS.
      - ksk 9y ago
        Indeed, this bug is a yowzer.
- stefan_ 9y ago
  This one apparently meant that something intentionally mapped for kernel access only was now accessible from userland. That is exactly the tedious, boring issue someone manually testing a bunch of applications will never find, but unit tests are designed to.
- IncRnd 9y ago
  It wasn't an unknown bug. This was a fix for a known bug. The point is that there was no test in place for memory isolation between users or processes. FYI, security testers call this type of testing negative testing, which is different from functional testing that is done to test an app works "properly". However, for an OS this test is not negative testing but functional testing if the OS is designed to enforce user and process isolation.
- asdsa5325 9y ago
  Testing to make sure you can't read from somewhere you are not supposed to read from seems like a pretty obvious test for an OS.
  - tedunangst 9y ago
    There are lots of places you're not supposed to read from. Does any operating system have 100% test coverage of addresses that aren't supposed to be readable?
    - PeterisP 9y ago
      IDK, there's a quite narrow whitelisted known range of addresses that should be readable by your process; you could (and should) certainly have an simple automated test that simply tries to read everything with the expectation that it should succeed only in known cases.
gerdesj 9y ago
Yes, how cute they put everything into a thingie designed by Linus, for Linux and it scales way beyond its original use case. There's probably a lesson there somewhere.
- zaat 9y ago
  Git is great, but no, actually it didn't scale and they had to develop GVFS for it to work. (https://blogs.msdn.microsoft.com/devops/2017/02/03/announcing-gvfs-git-virtual-file-system/ https://blogs.msdn.microsoft.com/devops/2017/02/03/announcin...)
  - gerdesj 9y ago
    "Today, we’re introducing GVFS (Git Virtual File System), which virtualizes the file system beneath your repo and makes it appear as though all the files in your repo are present, but in reality only downloads a file the first time it is opened." No, git works fine - that looks like an Engineer's bodge to account for an inadequacy elsewhere.
    - wtetzner 9y ago
      Huh? It's to avoid having to download the entire massive repo, which probably takes too much time to be a practical part of the developers' work flow.

egeozcan 9y ago

How can you test against an unknown bug?

maltalex 9y ago
> How can you test against an unknown bug? The point of testing is to make the unknown bugs, known.
- naasking 9y ago
  The point of testing is actually to ensure certain classes of known bugs aren't present. You can't test for bugs of which you have no knowledge.
  - deleted 9y ago
    [deleted]
  - IncRnd 9y ago
    In this case, however, an OS should have some sort of test in place that process and user isolation is being enforced. That is certainly a known situation that can be tested. It is also a selling point of the OS.
    - ksk 9y ago
      Indeed, this bug is a yowzer.
stefan_ 9y ago
This one apparently meant that something intentionally mapped for kernel access only was now accessible from userland. That is exactly the tedious, boring issue someone manually testing a bunch of applications will never find, but unit tests are designed to.
IncRnd 9y ago
It wasn't an unknown bug. This was a fix for a known bug. The point is that there was no test in place for memory isolation between users or processes. FYI, security testers call this type of testing negative testing, which is different from functional testing that is done to test an app works "properly". However, for an OS this test is not negative testing but functional testing if the OS is designed to enforce user and process isolation.
asdsa5325 9y ago
Testing to make sure you can't read from somewhere you are not supposed to read from seems like a pretty obvious test for an OS.
- tedunangst 9y ago
  There are lots of places you're not supposed to read from. Does any operating system have 100% test coverage of addresses that aren't supposed to be readable?
  - PeterisP 9y ago
    IDK, there's a quite narrow whitelisted known range of addresses that should be readable by your process; you could (and should) certainly have an simple automated test that simply tries to read everything with the expectation that it should succeed only in known cases.

gerdesj 9y ago

Yes, how cute they put everything into a thingie designed by Linus, for Linux and it scales way beyond its original use case. There's probably a lesson there somewhere.

zaat 9y ago
Git is great, but no, actually it didn't scale and they had to develop GVFS for it to work. (https://blogs.msdn.microsoft.com/devops/2017/02/03/announcing-gvfs-git-virtual-file-system/ https://blogs.msdn.microsoft.com/devops/2017/02/03/announcin...)
- gerdesj 9y ago
  "Today, we’re introducing GVFS (Git Virtual File System), which virtualizes the file system beneath your repo and makes it appear as though all the files in your repo are present, but in reality only downloads a file the first time it is opened." No, git works fine - that looks like an Engineer's bodge to account for an inadequacy elsewhere.
  - wtetzner 9y ago
    Huh? It's to avoid having to download the entire massive repo, which probably takes too much time to be a practical part of the developers' work flow.