On Tue, Aug 23, 2022 at 10:06 PM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > On Tue, Aug 23, 2022 at 09:19:58PM +0000, Andrew Delgadilo wrote: > > From: Andrew Delgadillo <adelg@xxxxxxxxxx> > > > > When testing a kernel, one of the earliest signals one can get is if a > > kernel has become tainted. For example, an organization might be > > interested in mass testing commits on their hardware. An obvious first > > step would be to make sure every commit boots, and a next step would be > > to make sure there are no warnings/crashes/lockups, hence the utility of > > a taint test. > > What's wrong with the tools/debugging/kernel-chktaint script? > > Why do we need another "get what the taint status is" program? The main functionality that this selftests has that kernel-chktaint does not is that it exits with a non-zero status code if the kernel is tainted. kernel-chktaint outputs information to stdout based on the taint status, but will always exit 0. The issue with this is that it cannot be plugged into a test runner that checks the exit code of a test script. In other words, if I wanted to plug it into git bisect, I would have to wrap kernel-chktaint in a command that transformed the output to an exit code. Sure that is doable, but it is not as simple as it could be. More concretely, I am setting kselftest runs against kernel commits (with a harness that logs kselftest runs into some other infrastructure), and such a test that is missing is a kselftest that checks the kernel's taint status. One could argue that one should just create a kselftest target that calls into kernel-chktaint and parse the output there to determine what the exit status is, but that seems fragile as a change in the underlying script could break it. For example, if I want to test for taint #18, and I am grepping for the string " * an in-kernel test has been run (#18)", I will actually get a false positive because the underlying script does not check for taint #18. Contrived example yes, but I think it shows that textual grepping for errors is error prone (as an aside, I'll send a patch to update the script to check for the new taint bit). > thanks, > > greg k-h
