Marco Elver 4933295622 kfence: shorten critical sections of alloc/free ...

Initializing memory and setting/checking the canary bytes is relatively
expensive, and doing so in the meta->lock critical sections extends the
duration with preemption and interrupts disabled unnecessarily.

Any reads to meta->addr and meta->size in kfence_guarded_alloc() and
kfence_guarded_free() don't require locking meta->lock as long as the
object is removed from the freelist: only kfence_guarded_alloc() sets
meta->addr and meta->size after removing it from the freelist, which
requires a preceding kfence_guarded_free() returning it to the list or
the initial state.

Therefore move reads to meta->addr and meta->size, including expensive
memory initialization using them, out of meta->lock critical sections.

Link: https://lkml.kernel.org/r/20210930153706.2105471-1-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Acked-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2021-11-06 13:30:43 -07:00

..

core.c

kfence: shorten critical sections of alloc/free

2021-11-06 13:30:43 -07:00

kfence_test.c

kfence: test: use kunit_skip() to skip tests

2021-11-06 13:30:43 -07:00

kfence.h

kfence: limit currently covered allocations when pool nearly full

2021-11-06 13:30:43 -07:00

Makefile

kfence: add test suite

2021-02-26 09:41:02 -08:00

report.c

Merge branch 'akpm' (patches from Andrew)

2021-09-08 12:55:35 -07:00