diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/obsolete/sysfs-kernel-kexec-kdump | 71 | ||||
| -rw-r--r-- | Documentation/ABI/testing/sysfs-kernel-kexec-kdump | 61 | ||||
| -rw-r--r-- | Documentation/admin-guide/dynamic-debug-howto.rst | 5 | ||||
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 20 | ||||
| -rw-r--r-- | Documentation/admin-guide/sysctl/kernel.rst | 32 | ||||
| -rw-r--r-- | Documentation/core-api/index.rst | 1 | ||||
| -rw-r--r-- | Documentation/core-api/kho/concepts.rst | 2 | ||||
| -rw-r--r-- | Documentation/core-api/liveupdate.rst | 61 | ||||
| -rw-r--r-- | Documentation/dev-tools/checkpatch.rst | 10 | ||||
| -rw-r--r-- | Documentation/driver-api/hw-recoverable-errors.rst | 60 | ||||
| -rw-r--r-- | Documentation/driver-api/index.rst | 1 | ||||
| -rw-r--r-- | Documentation/mm/index.rst | 1 | ||||
| -rw-r--r-- | Documentation/mm/memfd_preservation.rst | 23 | ||||
| -rw-r--r-- | Documentation/userspace-api/index.rst | 1 | ||||
| -rw-r--r-- | Documentation/userspace-api/ioctl/ioctl-number.rst | 2 | ||||
| -rw-r--r-- | Documentation/userspace-api/liveupdate.rst | 20 |
16 files changed, 355 insertions, 16 deletions
diff --git a/Documentation/ABI/obsolete/sysfs-kernel-kexec-kdump b/Documentation/ABI/obsolete/sysfs-kernel-kexec-kdump new file mode 100644 index 000000000000..ba26a6a1d2be --- /dev/null +++ b/Documentation/ABI/obsolete/sysfs-kernel-kexec-kdump @@ -0,0 +1,71 @@ +NOTE: all the ABIs listed in this file are deprecated and will be removed after 2028. + +Here are the alternative ABIs: ++------------------------------------+-----------------------------------------+ +| Deprecated | Alternative | ++------------------------------------+-----------------------------------------+ +| /sys/kernel/kexec_loaded | /sys/kernel/kexec/loaded | ++------------------------------------+-----------------------------------------+ +| /sys/kernel/kexec_crash_loaded | /sys/kernel/kexec/crash_loaded | ++------------------------------------+-----------------------------------------+ +| /sys/kernel/kexec_crash_size | /sys/kernel/kexec/crash_size | ++------------------------------------+-----------------------------------------+ +| /sys/kernel/crash_elfcorehdr_size | /sys/kernel/kexec/crash_elfcorehdr_size | ++------------------------------------+-----------------------------------------+ +| /sys/kernel/kexec_crash_cma_ranges | /sys/kernel/kexec/crash_cma_ranges | ++------------------------------------+-----------------------------------------+ + + +What: /sys/kernel/kexec_loaded +Date: Jun 2006 +Contact: kexec@lists.infradead.org +Description: read only + Indicates whether a new kernel image has been loaded + into memory using the kexec system call. It shows 1 if + a kexec image is present and ready to boot, or 0 if none + is loaded. +User: kexec tools, kdump service + +What: /sys/kernel/kexec_crash_loaded +Date: Jun 2006 +Contact: kexec@lists.infradead.org +Description: read only + Indicates whether a crash (kdump) kernel is currently + loaded into memory. It shows 1 if a crash kernel has been + successfully loaded for panic handling, or 0 if no crash + kernel is present. +User: Kexec tools, Kdump service + +What: /sys/kernel/kexec_crash_size +Date: Dec 2009 +Contact: kexec@lists.infradead.org +Description: read/write + Shows the amount of memory reserved for loading the crash + (kdump) kernel. It reports the size, in bytes, of the + crash kernel area defined by the crashkernel= parameter. + This interface also allows reducing the crashkernel + reservation by writing a smaller value, and the reclaimed + space is added back to the system RAM. +User: Kdump service + +What: /sys/kernel/crash_elfcorehdr_size +Date: Aug 2023 +Contact: kexec@lists.infradead.org +Description: read only + Indicates the preferred size of the memory buffer for the + ELF core header used by the crash (kdump) kernel. It defines + how much space is needed to hold metadata about the crashed + system, including CPU and memory information. This information + is used by the user space utility kexec to support updating the + in-kernel kdump image during hotplug operations. +User: Kexec tools + +What: /sys/kernel/kexec_crash_cma_ranges +Date: Nov 2025 +Contact: kexec@lists.infradead.org +Description: read only + Provides information about the memory ranges reserved from + the Contiguous Memory Allocator (CMA) area that are allocated + to the crash (kdump) kernel. It lists the start and end physical + addresses of CMA regions assigned for crashkernel use. +User: kdump service diff --git a/Documentation/ABI/testing/sysfs-kernel-kexec-kdump b/Documentation/ABI/testing/sysfs-kernel-kexec-kdump new file mode 100644 index 000000000000..f59051b5d96d --- /dev/null +++ b/Documentation/ABI/testing/sysfs-kernel-kexec-kdump @@ -0,0 +1,61 @@ +What: /sys/kernel/kexec/* +Date: Nov 2025 +Contact: kexec@lists.infradead.org +Description: + The /sys/kernel/kexec/* directory contains sysfs files + that provide information about the configuration status + of kexec and kdump. + +What: /sys/kernel/kexec/loaded +Date: Nov 2025 +Contact: kexec@lists.infradead.org +Description: read only + Indicates whether a new kernel image has been loaded + into memory using the kexec system call. It shows 1 if + a kexec image is present and ready to boot, or 0 if none + is loaded. +User: kexec tools, kdump service + +What: /sys/kernel/kexec/crash_loaded +Date: Nov 2025 +Contact: kexec@lists.infradead.org +Description: read only + Indicates whether a crash (kdump) kernel is currently + loaded into memory. It shows 1 if a crash kernel has been + successfully loaded for panic handling, or 0 if no crash + kernel is present. +User: Kexec tools, Kdump service + +What: /sys/kernel/kexec/crash_size +Date: Nov 2025 +Contact: kexec@lists.infradead.org +Description: read/write + Shows the amount of memory reserved for loading the crash + (kdump) kernel. It reports the size, in bytes, of the + crash kernel area defined by the crashkernel= parameter. + This interface also allows reducing the crashkernel + reservation by writing a smaller value, and the reclaimed + space is added back to the system RAM. +User: Kdump service + +What: /sys/kernel/kexec/crash_elfcorehdr_size +Date: Nov 2025 +Contact: kexec@lists.infradead.org +Description: read only + Indicates the preferred size of the memory buffer for the + ELF core header used by the crash (kdump) kernel. It defines + how much space is needed to hold metadata about the crashed + system, including CPU and memory information. This information + is used by the user space utility kexec to support updating the + in-kernel kdump image during hotplug operations. +User: Kexec tools + +What: /sys/kernel/kexec/crash_cma_ranges +Date: Nov 2025 +Contact: kexec@lists.infradead.org +Description: read only + Provides information about the memory ranges reserved from + the Contiguous Memory Allocator (CMA) area that are allocated + to the crash (kdump) kernel. It lists the start and end physical + addresses of CMA regions assigned for crashkernel use. +User: kdump service diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst index 7c036590cd07..095a63892257 100644 --- a/Documentation/admin-guide/dynamic-debug-howto.rst +++ b/Documentation/admin-guide/dynamic-debug-howto.rst @@ -223,12 +223,13 @@ The flags are:: f Include the function name s Include the source file name l Include line number + d Include call trace For ``print_hex_dump_debug()`` and ``print_hex_dump_bytes()``, only the ``p`` flag has meaning, other flags are ignored. -Note the regexp ``^[-+=][fslmpt_]+$`` matches a flags specification. -To clear all flags at once, use ``=_`` or ``-fslmpt``. +Note the regexp ``^[-+=][fslmptd_]+$`` matches a flags specification. +To clear all flags at once, use ``=_`` or ``-fslmptd``. Debug messages during Boot Process diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index b242519f57da..b86b6d946d88 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2114,14 +2114,20 @@ Kernel parameters the added memory block itself do not be affected. hung_task_panic= - [KNL] Should the hung task detector generate panics. - Format: 0 | 1 + [KNL] Number of hung tasks to trigger kernel panic. + Format: <int> + + When set to a non-zero value, a kernel panic will be triggered if + the number of detected hung tasks reaches this value. + + 0: don't panic + 1: panic immediately on first hung task + N: panic after N hung tasks are detected in a single scan - A value of 1 instructs the kernel to panic when a - hung task is detected. The default value is controlled - by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time - option. The value selected by this boot parameter can - be changed later by the kernel.hung_task_panic sysctl. + The default value is controlled by the + CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time option. The value + selected by this boot parameter can be changed later by the + kernel.hung_task_panic sysctl. hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC) terminal devices. Valid values: 0..8 diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index f3ee807b5d8b..239da22c4e28 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -397,13 +397,14 @@ a hung task is detected. hung_task_panic =============== -Controls the kernel's behavior when a hung task is detected. +When set to a non-zero value, a kernel panic will be triggered if the +number of hung tasks found during a single scan reaches this value. This file shows up if ``CONFIG_DETECT_HUNG_TASK`` is enabled. -= ================================================= += ======================================================= 0 Continue operation. This is the default behavior. -1 Panic immediately. -= ================================================= +N Panic when N hung tasks are found during a single scan. += ======================================================= hung_task_check_count @@ -421,6 +422,11 @@ the system boot. This file shows up if ``CONFIG_DETECT_HUNG_TASK`` is enabled. +hung_task_sys_info +================== +A comma separated list of extra system information to be dumped when +hung task is detected, for example, "tasks,mem,timers,locks,...". +Refer 'panic_sys_info' section below for more details. hung_task_timeout_secs ====================== @@ -515,6 +521,15 @@ default), only processes with the CAP_SYS_ADMIN capability may create io_uring instances. +kernel_sys_info +=============== +A comma separated list of extra system information to be dumped when +soft/hard lockup is detected, for example, "tasks,mem,timers,locks,...". +Refer 'panic_sys_info' section below for more details. + +It serves as the default kernel control knob, which will take effect +when a kernel module calls sys_info() with parameter==0. + kexec_load_disabled =================== @@ -576,6 +591,11 @@ if leaking kernel pointer values to unprivileged users is a concern. When ``kptr_restrict`` is set to 2, kernel pointers printed using %pK will be replaced with 0s regardless of privileges. +softlockup_sys_info & hardlockup_sys_info +========================================= +A comma separated list of extra system information to be dumped when +soft/hard lockup is detected, for example, "tasks,mem,timers,locks,...". +Refer 'panic_sys_info' section below for more details. modprobe ======== @@ -910,8 +930,8 @@ to 'panic_print'. Possible values are: ============= =================================================== tasks print all tasks info mem print system memory info -timer print timers info -lock print locks info if CONFIG_LOCKDEP is on +timers print timers info +locks print locks info if CONFIG_LOCKDEP is on ftrace print ftrace buffer all_bt print all CPUs backtrace (if available in the arch) blocked_tasks print only tasks in uninterruptible (blocked) state diff --git a/Documentation/core-api/index.rst b/Documentation/core-api/index.rst index 6cbdcbfa79c3..5eb0fbbbc323 100644 --- a/Documentation/core-api/index.rst +++ b/Documentation/core-api/index.rst @@ -138,6 +138,7 @@ Documents that don't fit elsewhere or which have yet to be categorized. :maxdepth: 1 librs + liveupdate netlink .. only:: subproject and html diff --git a/Documentation/core-api/kho/concepts.rst b/Documentation/core-api/kho/concepts.rst index 36d5c05cfb30..d626d1dbd678 100644 --- a/Documentation/core-api/kho/concepts.rst +++ b/Documentation/core-api/kho/concepts.rst @@ -70,5 +70,5 @@ in the FDT. That state is called the KHO finalization phase. Public API ========== -.. kernel-doc:: kernel/kexec_handover.c +.. kernel-doc:: kernel/liveupdate/kexec_handover.c :export: diff --git a/Documentation/core-api/liveupdate.rst b/Documentation/core-api/liveupdate.rst new file mode 100644 index 000000000000..7960eb15a81f --- /dev/null +++ b/Documentation/core-api/liveupdate.rst @@ -0,0 +1,61 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======================== +Live Update Orchestrator +======================== +:Author: Pasha Tatashin <pasha.tatashin@soleen.com> + +.. kernel-doc:: kernel/liveupdate/luo_core.c + :doc: Live Update Orchestrator (LUO) + +LUO Sessions +============ +.. kernel-doc:: kernel/liveupdate/luo_session.c + :doc: LUO Sessions + +LUO Preserving File Descriptors +=============================== +.. kernel-doc:: kernel/liveupdate/luo_file.c + :doc: LUO File Descriptors + +Live Update Orchestrator ABI +============================ +.. kernel-doc:: include/linux/kho/abi/luo.h + :doc: Live Update Orchestrator ABI + +The following types of file descriptors can be preserved + +.. toctree:: + :maxdepth: 1 + + ../mm/memfd_preservation + +Public API +========== +.. kernel-doc:: include/linux/liveupdate.h + +.. kernel-doc:: include/linux/kho/abi/luo.h + :functions: + +.. kernel-doc:: kernel/liveupdate/luo_core.c + :export: + +.. kernel-doc:: kernel/liveupdate/luo_file.c + :export: + +Internal API +============ +.. kernel-doc:: kernel/liveupdate/luo_core.c + :internal: + +.. kernel-doc:: kernel/liveupdate/luo_session.c + :internal: + +.. kernel-doc:: kernel/liveupdate/luo_file.c + :internal: + +See Also +======== + +- :doc:`Live Update uAPI </userspace-api/liveupdate>` +- :doc:`/core-api/kho/concepts` diff --git a/Documentation/dev-tools/checkpatch.rst b/Documentation/dev-tools/checkpatch.rst index dfaad0a279ff..fa2988dd4657 100644 --- a/Documentation/dev-tools/checkpatch.rst +++ b/Documentation/dev-tools/checkpatch.rst @@ -1238,6 +1238,16 @@ Others The patch file does not appear to be in unified-diff format. Please regenerate the patch file before sending it to the maintainer. + **PLACEHOLDER_USE** + Detects unhandled placeholder text left in cover letters or commit headers/logs. + Common placeholders include lines like:: + + *** SUBJECT HERE *** + *** BLURB HERE *** + + These typically come from autogenerated templates. Replace them with a proper + subject and description before sending. + **PRINTF_0XDECIMAL** Prefixing 0x with decimal output is defective and should be corrected. diff --git a/Documentation/driver-api/hw-recoverable-errors.rst b/Documentation/driver-api/hw-recoverable-errors.rst new file mode 100644 index 000000000000..fc526c3454bd --- /dev/null +++ b/Documentation/driver-api/hw-recoverable-errors.rst @@ -0,0 +1,60 @@ +.. 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. + diff --git a/Documentation/driver-api/index.rst b/Documentation/driver-api/index.rst index baff96b5cf0b..1833e6a0687e 100644 --- a/Documentation/driver-api/index.rst +++ b/Documentation/driver-api/index.rst @@ -97,6 +97,7 @@ Subsystem-specific APIs gpio/index hsi hte/index + hw-recoverable-errors i2c iio/index infiniband diff --git a/Documentation/mm/index.rst b/Documentation/mm/index.rst index ba6a8872849b..7aa2a8886908 100644 --- a/Documentation/mm/index.rst +++ b/Documentation/mm/index.rst @@ -48,6 +48,7 @@ documentation, or deleted if it has served its purpose. hugetlbfs_reserv ksm memory-model + memfd_preservation mmu_notifier multigen_lru numa diff --git a/Documentation/mm/memfd_preservation.rst b/Documentation/mm/memfd_preservation.rst new file mode 100644 index 000000000000..66e0fb6d5ef0 --- /dev/null +++ b/Documentation/mm/memfd_preservation.rst @@ -0,0 +1,23 @@ +.. SPDX-License-Identifier: GPL-2.0-or-later + +========================== +Memfd Preservation via LUO +========================== + +.. kernel-doc:: mm/memfd_luo.c + :doc: Memfd Preservation via LUO + +Memfd Preservation ABI +====================== + +.. kernel-doc:: include/linux/kho/abi/memfd.h + :doc: DOC: memfd Live Update ABI + +.. kernel-doc:: include/linux/kho/abi/memfd.h + :internal: + +See Also +======== + +- :doc:`/core-api/liveupdate` +- :doc:`/core-api/kho/concepts` diff --git a/Documentation/userspace-api/index.rst b/Documentation/userspace-api/index.rst index b8c73be4fb11..8a61ac4c1bf1 100644 --- a/Documentation/userspace-api/index.rst +++ b/Documentation/userspace-api/index.rst @@ -61,6 +61,7 @@ Everything else :maxdepth: 1 ELF + liveupdate netlink/index sysfs-platform_profile vduse diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst index 7c527a01d1cf..7232b3544cec 100644 --- a/Documentation/userspace-api/ioctl/ioctl-number.rst +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst @@ -385,6 +385,8 @@ Code Seq# Include File Comments 0xB8 01-02 uapi/misc/mrvl_cn10k_dpi.h Marvell CN10K DPI driver 0xB8 all uapi/linux/mshv.h Microsoft Hyper-V /dev/mshv driver <mailto:linux-hyperv@vger.kernel.org> +0xBA 00-0F uapi/linux/liveupdate.h Pasha Tatashin + <mailto:pasha.tatashin@soleen.com> 0xC0 00-0F linux/usb/iowarrior.h 0xCA 00-0F uapi/misc/cxl.h Dead since 6.15 0xCA 10-2F uapi/misc/ocxl.h diff --git a/Documentation/userspace-api/liveupdate.rst b/Documentation/userspace-api/liveupdate.rst new file mode 100644 index 000000000000..41c0473e4f16 --- /dev/null +++ b/Documentation/userspace-api/liveupdate.rst @@ -0,0 +1,20 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================ +Live Update uAPI +================ +:Author: Pasha Tatashin <pasha.tatashin@soleen.com> + +ioctl interface +=============== +.. kernel-doc:: kernel/liveupdate/luo_core.c + :doc: LUO ioctl Interface + +ioctl uAPI +=========== +.. kernel-doc:: include/uapi/linux/liveupdate.h + +See Also +======== + +- :doc:`Live Update Orchestrator </core-api/liveupdate>` |