docs: kernel-parameters: add kfence parameters

Add a brief summary for KFENCE's kernel command-line parameters in
admin-guide/kernel-parameters.

Link: https://lkml.kernel.org/r/20251222150018.1349672-1-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a8d0afde7f85a506b827ae31d48fc5d9dbabc095..1058f2a6d6a8c2e6a7153917b3c4d4312d57a8a0 100644 (file)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2917,6 +2917,41 @@ Kernel parameters
                        for Movable pages.  "nn[KMGTPE]", "nn%", and "mirror"
                        are exclusive, so you cannot specify multiple forms.
 
+       kfence.burst=   [MM,KFENCE] The number of additional successive
+                       allocations to be attempted through KFENCE for each
+                       sample interval.
+                       Format: <unsigned integer>
+                       Default: 0
+
+       kfence.check_on_panic=
+                       [MM,KFENCE] Whether to check all KFENCE-managed objects'
+                       canaries on panic.
+                       Format: <bool>
+                       Default: false
+
+       kfence.deferrable=
+                       [MM,KFENCE] Whether to use a deferrable timer to trigger
+                       allocations. This avoids forcing CPU wake-ups if the
+                       system is idle, at the risk of a less predictable
+                       sample interval.
+                       Format: <bool>
+                       Default: CONFIG_KFENCE_DEFERRABLE
+
+       kfence.sample_interval=
+                       [MM,KFENCE] KFENCE's sample interval in milliseconds.
+                       Format: <unsigned integer>
+                        0 - Disable KFENCE.
+                       >0 - Enabled KFENCE with given sample interval.
+                       Default: CONFIG_KFENCE_SAMPLE_INTERVAL
+
+       kfence.skip_covered_thresh=
+                       [MM,KFENCE] If pool utilization reaches this threshold
+                       (pool usage%), KFENCE limits currently covered
+                       allocations of the same source from further filling
+                       up the pool.
+                       Format: <unsigned integer>
+                       Default: 75
+
        kgdbdbgp=       [KGDB,HW,EARLY] kgdb over EHCI usb debug port.
                        Format: <Controller#>[,poll interval]
                        The controller # is the number of the ehci usb debug