On Tue, 26 Jun 2018 15:15:10 +0200 Andrey Konovalov <andreyknvl@xxxxxxxxxx> wrote: > This patchset adds a new mode to KASAN [1], which is called KHWASAN > (Kernel HardWare assisted Address SANitizer). > > The plan is to implement HWASan [2] for the kernel with the incentive, > that it's going to have comparable to KASAN performance, but in the same > time consume much less memory, trading that off for somewhat imprecise > bug detection and being supported only for arm64. Why do we consider this to be a worthwhile change? Is KASAN's memory consumption actually a significant problem? Some data regarding that would be very useful. If it is a large problem then we still have that problem on x86, so the problem remains largely unsolved? > ====== Benchmarks > > The following numbers were collected on Odroid C2 board. Both KASAN and > KHWASAN were used in inline instrumentation mode. > > Boot time [1]: > * ~1.7 sec for clean kernel > * ~5.0 sec for KASAN > * ~5.0 sec for KHWASAN > > Slab memory usage after boot [2]: > * ~40 kb for clean kernel > * ~105 kb + 1/8th shadow ~= 118 kb for KASAN > * ~47 kb + 1/16th shadow ~= 50 kb for KHWASAN > > Network performance [3]: > * 8.33 Gbits/sec for clean kernel > * 3.17 Gbits/sec for KASAN > * 2.85 Gbits/sec for KHWASAN > > Note, that KHWASAN (compared to KASAN) doesn't require quarantine. > > [1] Time before the ext4 driver is initialized. > [2] Measured as `cat /proc/meminfo | grep Slab`. > [3] Measured as `iperf -s & iperf -c 127.0.0.1 -t 30`. The above doesn't actually demonstrate the whole point of the patchset: to reduce KASAN's very high memory consumption?
