Messages in this thread | | | From | Peter Collingbourne <> | Date | Thu, 9 Dec 2021 14:12:03 -0800 | Subject | Re: [PATCH v3 0/6] kernel: introduce uaccess logging |
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On Wed, Dec 8, 2021 at 7:33 AM Marco Elver <elver@google.com> wrote: > > On Wed, 8 Dec 2021 at 05:48, Peter Collingbourne <pcc@google.com> wrote: > [...] > > Peter Collingbourne (6): > > include: split out uaccess instrumentation into a separate header > > uaccess-buffer: add core code > > fs: use copy_from_user_nolog() to copy mount() data > > uaccess-buffer: add CONFIG_GENERIC_ENTRY support > > arm64: add support for uaccess logging > > Documentation: document uaccess logging > > I think it needs to be possible to disable the feature via a Kconfig > option. Not all systems want or could even tolerate the additional > overheads -- even though you say they are minimal elsewhere. For > example, some embedded systems most likely have absolutely no use for > this feature, and the increase in .text might be unacceptable. Certain > features that we usually take for granted are no different (see > init/Kconfig: FUTEX, EPOLL, .. etc). If you'd like it enabled by > default, given the overheads are small enough, it can do "default y" > and be configurable only "if EXPERT".
Okay, done.
> Is it possible to add a kselftest-style test to > tools/testing/selftests? In addition to the basic tests, can certain > non-trivial properties, like masking of signals, also be tested? I > think that'd be extremely valuable, because I'm sure we'd have to > backport this to several older kernels.
Yes, I've added a new patch with a kselftest. (Good thing I did, because it (together with DEBUG_PREEMPT) uncovered a bug in the pre/post-exit-loop code. Fixed in v4.)
Peter
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