On Thu, Apr 18, 2019 at 5:42 PM Alexander Potapenko <glider@xxxxxxxxxx> wrote: > > Following the recent discussions here's another take at initializing > pages and heap objects with zeroes. This is needed to prevent possible > information leaks and make the control-flow bugs that depend on > uninitialized values more deterministic. > > The patchset introduces a new boot option, init_allocations, which > makes page allocator and SL[AOU]B initialize newly allocated memory. > init_allocations=0 doesn't (hopefully) add any overhead to the > allocation fast path (no noticeable slowdown on hackbench). > > With only the the first of the proposed patches the slowdown numbers are: > - 1.1% (stdev 0.2%) sys time slowdown building Linux kernel > - 3.1% (stdev 0.3%) sys time slowdown on af_inet_loopback benchmark > - 9.4% (stdev 0.5%) sys time slowdown on hackbench > > The second patch introduces a GFP flag that allows to disable > initialization for certain allocations. The third page is an example of > applying it to af_unix.c, which helps hackbench greatly. > > Slowdown numbers for the whole patchset are: > - 1.8% (stdev 0.8%) on kernel build > - 6.5% (stdev 0.2%) on af_inet_loopback > - 0.12% (stdev 0.6%) on hackbench > > > Alexander Potapenko (3): > mm: security: introduce the init_allocations=1 boot option > gfp: mm: introduce __GFP_NOINIT > net: apply __GFP_NOINIT to AF_UNIX sk_buff allocations Oops, I was hoping git send-email would pull all the Cc: tags from the patches and actually use them. > drivers/infiniband/core/uverbs_ioctl.c | 2 +- > include/linux/gfp.h | 6 ++++- > include/linux/mm.h | 8 +++++++ > include/linux/slab_def.h | 1 + > include/linux/slub_def.h | 1 + > include/net/sock.h | 5 +++++ > kernel/kexec_core.c | 4 ++-- > mm/dmapool.c | 2 +- > mm/page_alloc.c | 18 ++++++++++++++- > mm/slab.c | 14 ++++++------ > mm/slab.h | 1 + > mm/slab_common.c | 15 +++++++++++++ > mm/slob.c | 3 ++- > mm/slub.c | 9 ++++---- > net/core/sock.c | 31 +++++++++++++++++++++----- > net/unix/af_unix.c | 13 ++++++----- > 16 files changed, 104 insertions(+), 29 deletions(-) > > -- > 2.21.0.392.gf8f6787159e-goog > -- Alexander Potapenko Software Engineer Google Germany GmbH Erika-Mann-Straße, 33 80636 München Geschäftsführer: Paul Manicle, Halimah DeLaine Prado Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg
