On April 25, 2025 6:32:59 AM PDT, Christoph Hellwig <hch@xxxxxx> wrote: >On Fri, Apr 25, 2025 at 12:12:36PM +0200, Christian Brauner wrote: >> > That is: if dev_mynode(dev, inode) is not true some random value will be returned. >> >> Don't bother resending, Christoph. >> I've already fixed this with int err = 0 in the tree. > >Thanks! Let me use this as a platform to rant about our option >defaults and/or gcc error handling. It seems like ever since we started >zeroing on-stack variables by default gcc stopped warnings about using >uninitialized on-stack variables, leading to tons of these case where >we don't catch uninitialized variables. Now in this and in many cases >the code works fine because it assumed zero initialization, but there are >also cases where it didn't, leading to new bugs. This isn't the case: the feature was explicitly designed in both GCC and Clang to not disrupt -Wuninitialized. But -Wuninitialized has been so flakey for so long that it is almost useless (there was even -Wmaybe-uninitialized added to try to cover some of the missed diagnostics). And it's one of the many reasons stack variable zeroing is so important, since so much goes undiagnosed. :( >Can we fix this somehow? Fixing -Wuninitialized would be lovely, but it seems no one has been able to for years now. 😭 -- Kees Cook
