Merge tag 'hardening-v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees...

[platform/kernel/linux-starfive.git] / Documentation / admin-guide / sysctl / kernel.rst

diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
index 179bd30..659d7bc 100644 (file)
--- a/Documentation/admin-guide/sysctl/kernel.rst
+++ b/Documentation/admin-guide/sysctl/kernel.rst
@@ -139,6 +139,8 @@ Highest valid capability of the running kernel.  Exports
 ``CAP_LAST_CAP`` from the kernel.
 
 
+.. _core_pattern:
+
 core_pattern
 ============
 
@@ -174,6 +176,7 @@ core_pattern
        %f              executable filename
        %E              executable path
        %c              maximum size of core file by resource limit RLIMIT_CORE
+       %C              CPU the task ran on
        %<OTHER>        both are dropped
        ========        ==========================================
 
@@ -1323,6 +1326,29 @@ watchdog work to be queued by the watchdog timer function, otherwise the NMI
 watchdog — if enabled — can detect a hard lockup condition.
 
 
+split_lock_mitigate (x86 only)
+==============================
+
+On x86, each "split lock" imposes a system-wide performance penalty. On larger
+systems, large numbers of split locks from unprivileged users can result in
+denials of service to well-behaved and potentially more important users.
+
+The kernel mitigates these bad users by detecting split locks and imposing
+penalties: forcing them to wait and only allowing one core to execute split
+locks at a time.
+
+These mitigations can make those bad applications unbearably slow. Setting
+split_lock_mitigate=0 may restore some application performance, but will also
+increase system exposure to denial of service attacks from split lock users.
+
+= ===================================================================
+0 Disable the mitigation mode - just warns the split lock on kernel log
+  and exposes the system to denials of service from the split lockers.
+1 Enable the mitigation mode (this is the default) - penalizes the split
+  lockers with intentional performance degradation.
+= ===================================================================
+
+
 stack_erasing
 =============