[PATCH v2 2/2] docs: add ABI documentation for /sys/kernel/hwerr_recovery_stats/

Breno Leitao
2026-02-02T14:28:34Z

Document the new hwerr_recovery_stats sysfs directory that exposes
hardware error recovery statistics.

Update hw-recoverable-errors.rst to reference the new sysfs interface
for runtime monitoring.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
.../ABI/testing/sysfs-kernel-hwerr_recovery_stats | 47 ++++++++++++++++++++++
Documentation/driver-api/hw-recoverable-errors.rst | 3 +-
2 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/sysfs-kernel-hwerr_recovery_stats b/Documentation/ABI/testing/sysfs-kernel-hwerr_recovery_stats
new file mode 100644
index 0000000000000..4cb9f5a89fba9
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-kernel-hwerr_recovery_stats
@@ -0,0 +1,47 @@
+What: /sys/kernel/hwerr_recovery_stats/
+Date: February 2026
+KernelVersion: 6.20
+Contact: Breno Leitao <leitao@debian.org>
+Description:
+ Directory containing hardware error recovery statistics.
+ These statistics track recoverable hardware errors that the
+ kernel has handled since boot.
+
+ Each file contains a single integer representing the count
+ of recovered errors for that subsystem.
+
+What: /sys/kernel/hwerr_recovery_stats/cpu
+Date: February 2026
+KernelVersion: 6.20
+Contact: Breno Leitao <leitao@debian.org>
+Description:
+ Count of CPU-related recovered errors (MCE, ARM processor
+ errors).
+
+What: /sys/kernel/hwerr_recovery_stats/memory
+Date: February 2026
+KernelVersion: 6.20
+Contact: Breno Leitao <leitao@debian.org>
+Description:
+ Count of memory-related recovered errors.
+
+What: /sys/kernel/hwerr_recovery_stats/pci
+Date: February 2026
+KernelVersion: 6.20
+Contact: Breno Leitao <leitao@debian.org>
+Description:
+ Count of PCI/PCIe AER non-fatal recovered errors.
+
+What: /sys/kernel/hwerr_recovery_stats/cxl
+Date: February 2026
+KernelVersion: 6.20
+Contact: Breno Leitao <leitao@debian.org>
+Description:
+ Count of CXL (Compute Express Link) recovered errors.
+
+What: /sys/kernel/hwerr_recovery_stats/others
+Date: February 2026
+KernelVersion: 6.20
+Contact: Breno Leitao <leitao@debian.org>
+Description:
+ Count of other hardware recovered errors.
diff --git a/Documentation/driver-api/hw-recoverable-errors.rst b/Documentation/driver-api/hw-recoverable-errors.rst
index fc526c3454bd7..4aefcd103be22 100644
--- a/Documentation/driver-api/hw-recoverable-errors.rst
+++ b/Documentation/driver-api/hw-recoverable-errors.rst
@@ -36,7 +36,8 @@ Data Exposure and Consumption
types like CPU, memory, PCI, CXL, and others.
- It is exposed via vmcoreinfo crash dump notes and can be read using tools
like `crash`, `drgn`, or other kernel crash analysis utilities.
-- There is no other way to read these data other than from crash dumps.
+- It is also exposed via sysfs at ``/sys/kernel/hwerr_recovery_stats/`` for runtime
+ monitoring without requiring a crash dump.
- These errors are divided by area, which includes CPU, Memory, PCI, CXL and
others.

--
2.47.3