On Tue, Nov 09, 2021 at 06:19:54PM +0100, Marco Elver wrote: > Dear stable maintainers, > > We propose picking the following 2 patches to 5.15.y: > > 07e8481d3c38 kfence: always use static branches to guard kfence_alloc() > 4f612ed3f748 kfence: default to dynamic branch instead of static keys mode > > , which had not been marked for stable initially, but upon re-evaluation > conclude that it will also avoid various unexpected behaviours [1], [2] > as the use of frequently-switched static keys (at least on x86) is more > trouble than it's worth. > > [1] https://lkml.kernel.org/r/CANpmjNOw--ZNyhmn-GjuqU+aH5T98HMmBoCM4z=JFvajC913Qg@xxxxxxxxxxxxxx > [2] https://patchwork.kernel.org/project/linux-acpi/patch/2618833.mvXUDI8C0e@kreacher/ > > While optional, we recommend 07e8481d3c38 as well, as it avoids the > dynamic branch, now the default, if kfence is disabled at boot. > > The main thing is to make the default less troublesome and be more > conservative. Those choosing to enable CONFIG_KFENCE_STATIC_KEYS can > still do so, but requires a deliberate opt-in via a config change. Both now queued up, thanks. greg k-h
