On Tue, Jun 30, 2020 at 03:28:49PM +0900, Tetsuo Handa wrote: > On 2020/06/30 5:19, Eric W. Biederman wrote: > > Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> writes: > > > >> On 2020/06/29 4:44, Alexei Starovoitov wrote: > >>> But all the defensive programming kinda goes against general kernel style. > >>> I wouldn't do it. Especially pr_info() ?! > >>> Though I don't feel strongly about it. > >> > >> Honestly speaking, caller should check for errors and print appropriate > >> messages. info->wd.mnt->mnt_root != info->wd.dentry indicates that something > >> went wrong (maybe memory corruption). But other conditions are not fatal. > >> That is, I consider even pr_info() here should be unnecessary. > > > > They were all should never happen cases. Which is why my patches do: > > if (WARN_ON_ONCE(...)) > > No. Fuzz testing (which uses panic_on_warn=1) will trivially hit them. I don't believe that's true. Please show fuzzing stack trace to prove your point.