On Thu, 21 Apr 2022 15:28:45 +0200, Marco Elver <elver@xxxxxxxxxx> wrote: > On Thu, 21 Apr 2022 at 15:06, Alexander Potapenko <glider@xxxxxxxxxx> wrote: > [...] > > This report will denote that in a system that could have been running for days a particular skbuff was corrupted by some unknown task at some unknown point in time. > > How do we figure out what exactly caused this corruption? > > > > When we deploy KFENCE at scale, it is rarely possible for the kernel developer to get access to the host that reported the bug and try to reproduce it. > > With that in mind, the report (plus the kernel source) must contain all the necessary information to address the bug, otherwise reporting it will result in wasting the developer's time. > > Moreover, if we report such bugs too often, our tool loses the credit, which is hard to regain. > > I second this - in particular we'll want this off in fuzzers etc., > because it'll just generate reports that nobody can use to debug an > issue. I do see the value in this in potentially narrowing the cause > of a panic, but that information is likely not enough to fully > diagnose the root cause of the panic - it might however prompt to > re-run with KASAN, or check if memory DIMMs are faulty etc. > > We can still have this feature, but I suggest to make it > off-by-default, and only enable via a boot param. I'd call it > 'kfence.check_on_panic'. For your setup, you can then use it to enable > where you see fit. I agree to give users the option to use this feature. > Thanks, >-- Marco
