A-Team_Digital_Solutions/android_kernel_motorola_sm6375
Watch
2
0
Fork
You've already forked android_kernel_motorola_sm6375
 0
mirror of https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git synced 2026-10-05 19:31:57 -04:00
Code Issues Projects Releases Packages Wiki Activity

FROMGIT: kfence: add option to use KFENCE without static keys

Browse source 
For certain usecases, specifically where the sample interval is always
set to a very low value such as 1ms, it can make sense to use a dynamic
branch instead of static branches due to the overhead of toggling a
static branch.

Therefore, add a new Kconfig option to remove the static branches and
instead check kfence_allocation_gate if a KFENCE allocation should be
set up.

Link: https://lkml.kernel.org/r/20210111091544.3287013-1-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Suggested-by: Jörn Engel <joern@purestorage.com>
Reviewed-by: Jörn Engel <joern@purestorage.com>
Cc: 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>

Bug: 177201466
(cherry picked from commit c01761611b325c1e4ec7d3e236cc9db003cb82fd
    https://github.com/hnaz/linux-mm v5.11-rc4-mmots-2021-01-21-20-10)
Test: CONFIG_KFENCE_KUNIT_TEST=y passes on Cuttlefish
Signed-off-by: Alexander Potapenko <glider@google.com>
Change-Id: I68a112a8ff68fa24742b198e036f130a9757c27f
This commit is contained in:
Marco Elver 2021-01-22 09:18:33 +00:00 • committed by Michael Bestas
commit 9339667c95
No known key found for this signature in database
GPG key ID: CC95044519BE6669
3 changed files with 39 additions and 16 deletions
Download patch file Download diff file Expand all files Collapse all files

12
lib/Kconfig.kfence
View file

@ -6,7 +6,6 @@ config HAVE_ARCH_KFENCE
menuconfig KFENCE
bool "KFENCE: low-overhead sampling-based memory safety error detector"
depends on HAVE_ARCH_KFENCE && !KASAN && (SLAB || SLUB)
depends on JUMP_LABEL # To ensure performance, require jump labels
select STACKTRACE
help
KFENCE is a low-overhead sampling-based detector of heap out-of-bounds
@ -23,6 +22,17 @@ menuconfig KFENCE
if KFENCE
config KFENCE_STATIC_KEYS
bool "Use static keys to set up allocations"
default y
depends on JUMP_LABEL # To ensure performance, require jump labels
help
Use static keys (static branches) to set up KFENCE allocations. Using
static keys is normally recommended, because it avoids a dynamic
branch in the allocator's fast path. However, with very low sample
intervals, or on systems that do not support jump labels, a dynamic
branch may still be an acceptable performance trade-off.
config KFENCE_SAMPLE_INTERVAL
int "Default sample interval in milliseconds"
default 100