projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 0ce20dd8 AP |
1 | # SPDX-License-Identifier: GPL-2.0-only |
| 2 | ||
| 3 | config HAVE_ARCH_KFENCE | |
| 4 | bool | |
| 5 | ||
| 6 | menuconfig KFENCE | |
| 7 | bool "KFENCE: low-overhead sampling-based memory safety error detector" | |
| 8 | depends on HAVE_ARCH_KFENCE && !KASAN && (SLAB || SLUB) | |
| 9 | select STACKTRACE | |
| 10 | help | |
| 11 | KFENCE is a low-overhead sampling-based detector of heap out-of-bounds | |
| 12 | access, use-after-free, and invalid-free errors. KFENCE is designed | |
| 13 | to have negligible cost to permit enabling it in production | |
| 14 | environments. | |
| 15 | ||
| 16 | Note that, KFENCE is not a substitute for explicit testing with tools | |
| 17 | such as KASAN. KFENCE can detect a subset of bugs that KASAN can | |
| 18 | detect, albeit at very different performance profiles. If you can | |
| 19 | afford to use KASAN, continue using KASAN, for example in test | |
| 20 | environments. If your kernel targets production use, and cannot | |
| 21 | enable KASAN due to its cost, consider using KFENCE. | |
| 22 | ||
| 23 | if KFENCE | |
| 24 | ||
| 25 | config KFENCE_STATIC_KEYS | |
| 26 | bool "Use static keys to set up allocations" | |
| 27 | default y | |
| 28 | depends on JUMP_LABEL # To ensure performance, require jump labels | |
| 29 | help | |
| 30 | Use static keys (static branches) to set up KFENCE allocations. Using | |
| 31 | static keys is normally recommended, because it avoids a dynamic | |
| 32 | branch in the allocator's fast path. However, with very low sample | |
| 33 | intervals, or on systems that do not support jump labels, a dynamic | |
| 34 | branch may still be an acceptable performance trade-off. | |
| 35 | ||
| 36 | config KFENCE_SAMPLE_INTERVAL | |
| 37 | int "Default sample interval in milliseconds" | |
| 38 | default 100 | |
| 39 | help | |
| 40 | The KFENCE sample interval determines the frequency with which heap | |
| 41 | allocations will be guarded by KFENCE. May be overridden via boot | |
| 42 | parameter "kfence.sample_interval". | |
| 43 | ||
| 44 | Set this to 0 to disable KFENCE by default, in which case only | |
| 45 | setting "kfence.sample_interval" to a non-zero value enables KFENCE. | |
| 46 | ||
| 47 | config KFENCE_NUM_OBJECTS | |
| 48 | int "Number of guarded objects available" | |
| 49 | range 1 65535 | |
| 50 | default 255 | |
| 51 | help | |
| 52 | The number of guarded objects available. For each KFENCE object, 2 | |
| 53 | pages are required; with one containing the object and two adjacent | |
| 54 | ones used as guard pages. | |
| 55 | ||
| 56 | config KFENCE_STRESS_TEST_FAULTS | |
| 57 | int "Stress testing of fault handling and error reporting" if EXPERT | |
| 58 | default 0 | |
| 59 | help | |
| 60 | The inverse probability with which to randomly protect KFENCE object | |
| 61 | pages, resulting in spurious use-after-frees. The main purpose of | |
| 62 | this option is to stress test KFENCE with concurrent error reports | |
| 63 | and allocations/frees. A value of 0 disables stress testing logic. | |
| 64 | ||
| 65 | Only for KFENCE testing; set to 0 if you are not a KFENCE developer. | |
| 66 | ||
| 67 | endif # KFENCE |