forked from Minki/linux
mainlining shenanigans
1a367063ca
When DLPAR adding or removing memory we need to check the device
offline status before trying to online/offline the memory. This is
needed because calls to device_online() and device_offline() will
return non-zero for memory that is already online and offline
respectively.
This update resolves two scenarios. First, for a kernel built with
auto-online memory enabled (CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=y),
memory will be onlined as part of calls to add_memory(). After adding
the memory the pseries DLPAR code tries to online it and fails since
the memory is already online. The DLPAR code then tries to remove the
memory which produces the oops message below because the memory is not
offline.
The second scenario occurs when removing memory that is already
offline, i.e. marking memory offline (via sysfs) and then trying to
remove that memory. This doesn't work because offlining the already
offline memory does not succeed and the DLPAR code then fails the
DLPAR remove operation.
The fix for both scenarios is to check the device.offline status
before making the calls to device_online() or device_offline().
kernel BUG at mm/memory_hotplug.c:1936!
...
NIP [c0000000002ca428] .remove_memory+0xb8/0xc0
LR [c0000000002ca3cc] .remove_memory+0x5c/0xc0
Call Trace:
.remove_memory+0x5c/0xc0 (unreliable)
.dlpar_add_lmb+0x384/0x400
.dlpar_memory+0x5dc/0xca0
.handle_dlpar_errorlog+0x74/0xe0
.pseries_hp_work_fn+0x2c/0x90
.process_one_work+0x17c/0x460
.worker_thread+0x88/0x500
.kthread+0x15c/0x1a0
.ret_from_kernel_thread+0x58/0xc0
Fixes:
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|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.