diff options
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/dynamic-debug-howto.rst | 5 | ||||
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 26 | ||||
| -rw-r--r-- | Documentation/admin-guide/sysctl/kernel.rst | 32 | ||||
| -rw-r--r-- | Documentation/admin-guide/thunderbolt.rst | 50 |
4 files changed, 78 insertions, 35 deletions
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 5692e19199b3..b86b6d946d88 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1211,12 +1211,8 @@ Kernel parameters debugfs= [KNL,EARLY] This parameter enables what is exposed to userspace and debugfs internal clients. - Format: { on, no-mount, off } + Format: { on, off } on: All functions are enabled. - no-mount: - Filesystem is not registered but kernel clients can - access APIs and a crashkernel can be used to read - its content. There is nothing to mount. off: Filesystem is not registered and clients get a -EPERM as result when trying to register files or directories within debugfs. @@ -2118,14 +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/admin-guide/thunderbolt.rst b/Documentation/admin-guide/thunderbolt.rst index 102c693c8f81..07303c1346fb 100644 --- a/Documentation/admin-guide/thunderbolt.rst +++ b/Documentation/admin-guide/thunderbolt.rst @@ -203,10 +203,10 @@ host controller or a device, it is important that the firmware can be upgraded to the latest where possible bugs in it have been fixed. Typically OEMs provide this firmware from their support site. -There is also a central site which has links where to download firmware -for some machines: - - `Thunderbolt Updates <https://thunderbolttechnology.net/updates>`_ +Currently, recommended method of updating firmware is through "fwupd" tool. +It uses LVFS (Linux Vendor Firmware Service) portal by default to get the +latest firmware from hardware vendors and updates connected devices if found +compatible. For details refer to: https://github.com/fwupd/fwupd. Before you upgrade firmware on a device, host or retimer, please make sure it is a suitable upgrade. Failing to do that may render the device @@ -215,18 +215,40 @@ tools! Host NVM upgrade on Apple Macs is not supported. -Once the NVM image has been downloaded, you need to plug in a -Thunderbolt device so that the host controller appears. It does not -matter which device is connected (unless you are upgrading NVM on a -device - then you need to connect that particular device). +Fwupd is installed by default. If you don't have it on your system, simply +use your distro package manager to get it. + +To see possible updates through fwupd, you need to plug in a Thunderbolt +device so that the host controller appears. It does not matter which +device is connected (unless you are upgrading NVM on a device - then you +need to connect that particular device). Note an OEM-specific method to power the controller up ("force power") may be available for your system in which case there is no need to plug in a Thunderbolt device. -After that we can write the firmware to the non-active parts of the NVM -of the host or device. As an example here is how Intel NUC6i7KYK (Skull -Canyon) Thunderbolt controller NVM is upgraded:: +Updating firmware using fwupd is straightforward - refer to official +readme on fwupd github. + +If firmware image is written successfully, the device shortly disappears. +Once it comes back, the driver notices it and initiates a full power +cycle. After a while device appears again and this time it should be +fully functional. + +Device of interest should display new version under "Current version" +and "Update State: Success" in fwupd's interface. + +Upgrading firmware manually +--------------------------------------------------------------- +If possible, use fwupd to updated the firmware. However, if your device OEM +has not uploaded the firmware to LVFS, but it is available for download +from their side, you can use method below to directly upgrade the +firmware. + +Manual firmware update can be done with 'dd' tool. To update firmware +using this method, you need to write it to the non-active parts of NVM +of the host or device. Example on how to update Intel NUC6i7KYK +(Skull Canyon) Thunderbolt controller NVM:: # dd if=KYK_TBT_FW_0018.bin of=/sys/bus/thunderbolt/devices/0-0/nvm_non_active0/nvmem @@ -235,10 +257,8 @@ upgrade process as follows:: # echo 1 > /sys/bus/thunderbolt/devices/0-0/nvm_authenticate -If no errors are returned, the host controller shortly disappears. Once -it comes back the driver notices it and initiates a full power cycle. -After a while the host controller appears again and this time it should -be fully functional. +If no errors are returned, device should behave as described in previous +section. We can verify that the new NVM firmware is active by running the following commands:: |