[PATCH 2/2] Documentation: document panic_on_unrecoverable_memory_failure sysctl

Breno Leitao
2026-03-23T16:17:45Z

Document the new vm.panic_on_unrecoverable_memory_failure sysctl in the
admin guide, following the same format as panic_on_unrecovered_nmi.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
Documentation/admin-guide/sysctl/vm.rst | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)

diff --git a/Documentation/admin-guide/sysctl/vm.rst b/Documentation/admin-guide/sysctl/vm.rst
index 97e12359775c9..3310fb8272fb9 100644
--- a/Documentation/admin-guide/sysctl/vm.rst
+++ b/Documentation/admin-guide/sysctl/vm.rst
@@ -67,6 +67,7 @@ Currently, these files are in /proc/sys/vm:
- page-cluster
- page_lock_unfairness
- panic_on_oom
+- panic_on_unrecoverable_memory_failure
- percpu_pagelist_high_fraction
- stat_interval
- stat_refresh
@@ -925,6 +926,32 @@ panic_on_oom=2+kdump gives you very strong tool to investigate
why oom happens. You can get snapshot.

+panic_on_unrecoverable_memory_failure
+======================================
+
+When a hardware memory error (e.g. multi-bit ECC) hits an in-use kernel
+page that cannot be recovered by the memory failure handler, the default
+behaviour is to ignore the error and continue operation. This is
+dangerous because the corrupted data remains accessible to the kernel,
+risking silent data corruption or a delayed crash when the poisoned
+memory is next accessed.
+
+Pages that reach this path include slab objects (dentry cache, inode
+cache, etc.), page tables, kernel stacks, and other kernel allocations
+that lack the reverse mapping needed to isolate all references.
+
+For many environments it is preferable to panic immediately with a clean
+crash dump that captures the original error context, rather than to
+continue and face a random crash later whose cause is difficult to
+diagnose.
+
+= ===================================================================
+0 Try to continue operation (default).
+1 Panic immediately. If the ``panic`` sysctl is also non-zero then the
+ machine will be rebooted.
+= ===================================================================
+
+
percpu_pagelist_high_fraction
=============================

--
2.52.0