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authorDave Airlie <airlied@redhat.com>2026-09-26 07:57:59 +1000
committerDave Airlie <airlied@redhat.com>2026-09-26 07:58:24 +1000
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treecc62d74e0eb4905246978674461e78e2f9df2afd /Documentation/driver-api/hw-recoverable-errors.rst
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Merge tag 'drm-misc-fixes-2026-09-24' of https://gitlab.freedesktop.org/drm/misc/kernel into drm-fixesgrafted
A number of fixes: - bridge: - samsung-dsim: fix GPIO lifetime - client: Null pointer dereference fix - imagination: error handling fix, page handling fix - nouveau: fix reference leaks, double-frees, out-of-bounds accesses, use-after-frees, don't reject config without SCDC, a number of workarounds - virtio: fix memory leak, reference leaks, null pointer dereference, add pixel blend mode, cache coherency fix Signed-off-by: Dave Airlie <airlied@redhat.com> From: Maxime Ripard <self@mripard.dev> Link: https://patch.msgid.link/arU22zzqUGDEco1y@houat
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+.. SPDX-License-Identifier: GPL-2.0
+
+=================================================
+Recoverable Hardware Error Tracking in vmcoreinfo
+=================================================
+
+Overview
+--------
+
+This feature provides a generic infrastructure within the Linux kernel to track
+and log recoverable hardware errors. These are hardware recoverable errors
+visible that might not cause immediate panics but may influence health, mainly
+because new code path will be executed in the kernel.
+
+By recording counts and timestamps of recoverable errors into the vmcoreinfo
+crash dump notes, this infrastructure aids post-mortem crash analysis tools in
+correlating hardware events with kernel failures. This enables faster triage
+and better understanding of root causes, especially in large-scale cloud
+environments where hardware issues are common.
+
+Benefits
+--------
+
+- Facilitates correlation of hardware recoverable errors with kernel panics or
+ unusual code paths that lead to system crashes.
+- Provides operators and cloud providers quick insights, improving reliability
+ and reducing troubleshooting time.
+- Complements existing full hardware diagnostics without replacing them.
+
+Data Exposure and Consumption
+-----------------------------
+
+- The tracked error data consists of per-error-type counts and timestamps of
+ last occurrence.
+- This data is stored in the `hwerror_data` array, categorized by error source
+ 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.
+- These errors are divided by area, which includes CPU, Memory, PCI, CXL and
+ others.
+
+Typical usage example (in drgn REPL):
+
+.. code-block:: python
+
+ >>> prog['hwerror_data']
+ (struct hwerror_info[HWERR_RECOV_MAX]){
+ {
+ .count = (int)844,
+ .timestamp = (time64_t)1752852018,
+ },
+ ...
+ }
+
+Enabling
+--------
+
+- This feature is enabled when CONFIG_VMCORE_INFO is set.
+