mirror of
https://github.com/torvalds/linux.git
synced 2026-07-29 10:41:49 +02:00
Linux kernel source tree
c6a809363a
Patch series "mm/memory_hotplug: fixup crash during uevent handling", v4. we have some udev rules trying to read the sysfs attribute 'valid_zones' during an memory 'add' event, causing a crash in zone_for_pfn_range(). Debugging found that mem->nid was set to NUMA_NO_NODE, which crashed in NODE_DATA(nid). Further analysis revealed that we're running into a race with udev event processing: add_memory_resource() has this function calls: 1) __try_online_node() 2) arch_add_memory() 3) create_memory_block_devices() -> calls device_register() -> memory 'add' event 4) node_set_online()/__register_one_node() -> calls device_register() -> node 'add' event 5) register_memory_blocks_under_node() -> sets mem->nid Which, to the uninitated, is ... weird ... Why do we try to online the node in 1), but only register the node in 4) _after_ we have created the memory blocks in 3) ? And why do we set the 'nid' value in 5), when the uevent (which might need to see the correct 'nid' value) is sent out in 3) ? There must be a reason, I'm sure ... So here's a small patchset to fixup uevent ordering. The first patch adds a 'nid' parameter to add_memory_blocks() (to avoid mem->nid being initialized with NUMA_NO_NODE), and the second patch reshuffles the code in add_memory_resource() to fully initialize the node prior to calling create_memory_block_devices() so that the node is valid at that time and uevent processing will see correct values in sysfs. This patch (of 3): We have some udev rules trying to read the sysfs attribute 'valid_zones' during an memory 'add' event, causing a crash in zone_for_pfn_range(). Debugging found that mem->nid was set to NUMA_NO_NODE, which crashed in NODE_DATA(nid). Further analysis revealed that we're running into a race with udev event processing: add_memory_resource() has this function calls: 1) __try_online_node() 2) arch_add_memory() 3) create_memory_block_devices() -> calls device_register() -> memory 'add' event 4) node_set_online()/__register_one_node() -> calls device_register() -> node 'add' event 5) register_memory_blocks_under_node() -> sets mem->nid Which, to the uninitated, is ... weird ... Why do we try to online the node in 1), but only register the node in 4) _after_ we have created the memory blocks in 3) ? And why do we set the 'nid' value in 5), when the uevent (which might need to see the correct 'nid' value) is sent out in 3) ? There must be a reason, I'm sure ... So here's a small patchset to fixup uevent ordering. The first patch adds a 'nid' parameter to add_memory_blocks() (to avoid mem->nid being initialized with NUMA_NO_NODE), and the second patch reshuffles the code in add_memory_resource() to fully initialize the node prior to calling create_memory_block_devices() so that the node is valid at that time and uevent processing will see correct values in sysfs. This patch (of 3): Add a 'nid' parameter to add_memory_block() to initialize the memory block with the correct node id. Link: https://lkml.kernel.org/r/20250729064637.51662-1-hare@kernel.org Link: https://lkml.kernel.org/r/20250729064637.51662-2-hare@kernel.org Signed-off-by: Hannes Reinecke <hare@kernel.org> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Donet Tom <donettom@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .pylintrc | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
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.