user/sven/linux.git/kernel/Kconfig.kexec, branch v6.17.10

kho: mm: don't allow deferred struct page with KHO

2025-08-19T23:35:53Z

KHO uses struct pages for the preserved memory early in boot, however, with deferred struct page initialization, only a small portion of memory has properly initialized struct pages. This problem was detected where vmemmap is poisoned, and illegal flag combinations are detected. Don't allow them to be enabled together, and later we will have to teach KHO to work properly with deferred struct page init kernel feature. Link: https://lkml.kernel.org/r/20250808201804.772010-3-pasha.tatashin@soleen.com Fixes: 4e1d010e3bda ("kexec: add config option for KHO") Signed-off-by: Pasha Tatashin Acked-by: Mike Rapoport (Microsoft) Acked-by: Pratyush Yadav Cc: Alexander Graf Cc: Arnd Bergmann Cc: Baoquan He Cc: Changyuan Lyu Cc: Coiby Xu Cc: Dave Vasilevsky Cc: Eric Biggers Cc: Kees Cook Cc: Signed-off-by: Andrew Morton

crashdump: add CONFIG_KEYS dependency

2025-06-25T22:55:04Z

The dm_crypt code fails to build without CONFIG_KEYS: kernel/crash_dump_dm_crypt.c: In function 'restore_dm_crypt_keys_to_thread_keyring': kernel/crash_dump_dm_crypt.c:105:9: error: unknown type name 'key_ref_t'; did you mean 'key_ref_put'? There is a mix of 'select KEYS' and 'depends on KEYS' in Kconfig, so there is no single obvious solution here, but generally using 'depends on' makes more sense and is less likely to cause dependency loops. Link: https://lkml.kernel.org/r/20250620112140.3396316-1-arnd@kernel.org Fixes: 62f17d9df692 ("crash_dump: retrieve dm crypt keys in kdump kernel") Signed-off-by: Arnd Bergmann Cc: Alexander Graf Cc: Baoquan He Cc: Coiby Xu Cc: Dave Vasilevsky Cc: Eric Biggers Cc: Michael Ellerman Signed-off-by: Andrew Morton

Merge tag 'mm-nonmm-stable-2025-05-31-15-28' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-06-01T02:12:53Z

Pull non-MM updates from Andrew Morton: - "hung_task: extend blocking task stacktrace dump to semaphore" from Lance Yang enhances the hung task detector. The detector presently dumps the blocking tasks's stack when it is blocked on a mutex. Lance's series extends this to semaphores - "nilfs2: improve sanity checks in dirty state propagation" from Wentao Liang addresses a couple of minor flaws in nilfs2 - "scripts/gdb: Fixes related to lx_per_cpu()" from Illia Ostapyshyn fixes a couple of issues in the gdb scripts - "Support kdump with LUKS encryption by reusing LUKS volume keys" from Coiby Xu addresses a usability problem with kdump. When the dump device is LUKS-encrypted, the kdump kernel may not have the keys to the encrypted filesystem. A full writeup of this is in the series [0/N] cover letter - "sysfs: add counters for lockups and stalls" from Max Kellermann adds /sys/kernel/hardlockup_count and /sys/kernel/hardlockup_count and /sys/kernel/rcu_stall_count - "fork: Page operation cleanups in the fork code" from Pasha Tatashin implements a number of code cleanups in fork.c - "scripts/gdb/symbols: determine KASLR offset on s390 during early boot" from Ilya Leoshkevich fixes some s390 issues in the gdb scripts * tag 'mm-nonmm-stable-2025-05-31-15-28' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (67 commits) llist: make llist_add_batch() a static inline delayacct: remove redundant code and adjust indentation squashfs: add optional full compressed block caching crash_dump, nvme: select CONFIGFS_FS as built-in scripts/gdb/symbols: determine KASLR offset on s390 during early boot scripts/gdb/symbols: factor out pagination_off() scripts/gdb/symbols: factor out get_vmlinux() kernel/panic.c: format kernel-doc comments mailmap: update and consolidate Casey Connolly's name and email nilfs2: remove wbc->for_reclaim handling fork: define a local GFP_VMAP_STACK fork: check charging success before zeroing stack fork: clean-up naming of vm_stack/vm_struct variables in vmap stacks code fork: clean-up ifdef logic around stack allocation kernel/rcu/tree_stall: add /sys/kernel/rcu_stall_count kernel/watchdog: add /sys/kernel/{hard,soft}lockup_count x86/crash: make the page that stores the dm crypt keys inaccessible x86/crash: pass dm crypt keys to kdump kernel Revert "x86/mm: Remove unused __set_memory_prot()" crash_dump: retrieve dm crypt keys in kdump kernel ...

crash_dump, nvme: select CONFIGFS_FS as built-in

2025-05-28T02:40:33Z

Configfs can be configured as a loadable module, which causes a link-time failure for dm-crypt crash dump support: crash_dump_dm_crypt.c:(.text+0x3a4): undefined reference to `config_item_init_type_name' aarch64-linux-ld: kernel/crash_dump_dm_crypt.o: in function `configfs_dmcrypt_keys_init': crash_dump_dm_crypt.c:(.init.text+0x90): undefined reference to `config_group_init' aarch64-linux-ld: crash_dump_dm_crypt.c:(.init.text+0xb4): undefined reference to `configfs_register_subsystem' aarch64-linux-ld: crash_dump_dm_crypt.c:(.init.text+0xd8): undefined reference to `configfs_unregister_subsystem' This could be avoided with a dependency on CONFIGFS_FS=y, but the dependency has an additional problem of causing Kconfig dependency loops since most other uses select the symbol. Using a simple 'select CONFIGFS_FS' here in turn fails with CONFIG_DM_CRYPT=m, because that still only causes configfs to be a loadable module. The only version I found that fixes this reliably uses an additional Kconfig symbol to ensure the 'select' actually turns on configfs as builtin, with two additional changes to avoid dependency loops with nvme and sysfs. There is no compile-time dependency between configfs and sysfs, so selecting configfs from a driver with sysfs disabled does not cause link failures, only the default /sys/kernel/config mount point will not be created. Link: https://lkml.kernel.org/r/20250521160359.2132363-1-arnd@kernel.org Fixes: 6b23858fd63b ("crash_dump: make dm crypt keys persist for the kdump kernel") Fixes: 1fb470408497 ("nvme-loop: add configfs dependency") Signed-off-by: Arnd Bergmann Cc: Andreas Hindborg Cc: Breno Leitao Cc: Chaitanya Kulkarni Cc: Christoph Hellwig Cc: Coiby Xu Cc: Jens Axboe Cc: Sagi Grimberg Signed-off-by: Andrew Morton

crash_dump: make dm crypt keys persist for the kdump kernel

2025-05-21T17:48:20Z

A configfs /sys/kernel/config/crash_dm_crypt_keys is provided for user space to make the dm crypt keys persist for the kdump kernel. Take the case of dumping to a LUKS-encrypted target as an example, here is the life cycle of the kdump copies of LUKS volume keys, 1. After the 1st kernel loads the initramfs during boot, systemd uses an user-input passphrase to de-crypt the LUKS volume keys or simply TPM-sealed volume keys and then save the volume keys to specified keyring (using the --link-vk-to-keyring API) and the keys will expire within specified time. 2. A user space tool (kdump initramfs loader like kdump-utils) create key items inside /sys/kernel/config/crash_dm_crypt_keys to inform the 1st kernel which keys are needed. 3. When the kdump initramfs is loaded by the kexec_file_load syscall, the 1st kernel will iterate created key items, save the keys to kdump reserved memory. 4. When the 1st kernel crashes and the kdump initramfs is booted, the kdump initramfs asks the kdump kernel to create a user key using the key stored in kdump reserved memory by writing yes to /sys/kernel/crash_dm_crypt_keys/restore. Then the LUKS encrypted device is unlocked with libcryptsetup's --volume-key-keyring API. 5. The system gets rebooted to the 1st kernel after dumping vmcore to the LUKS encrypted device is finished Eventually the keys have to stay in the kdump reserved memory for the kdump kernel to unlock encrypted volumes. During this process, some measures like letting the keys expire within specified time are desirable to reduce security risk. This patch assumes, 1) there are 128 LUKS devices at maximum to be unlocked thus MAX_KEY_NUM=128. 2) a key description won't exceed 128 bytes thus KEY_DESC_MAX_LEN=128. And here is a demo on how to interact with /sys/kernel/config/crash_dm_crypt_keys, # Add key #1 mkdir /sys/kernel/config/crash_dm_crypt_keys/7d26b7b4-e342-4d2d-b660-7426b0996720 # Add key #1's description echo cryptsetup:7d26b7b4-e342-4d2d-b660-7426b0996720 > /sys/kernel/config/crash_dm_crypt_keys/description # how many keys do we have now? cat /sys/kernel/config/crash_dm_crypt_keys/count 1 # Add key# 2 in the same way # how many keys do we have now? cat /sys/kernel/config/crash_dm_crypt_keys/count 2 # the tree structure of /crash_dm_crypt_keys configfs tree /sys/kernel/config/crash_dm_crypt_keys/ /sys/kernel/config/crash_dm_crypt_keys/ ├── 7d26b7b4-e342-4d2d-b660-7426b0996720 │ └── description ├── count ├── fce2cd38-4d59-4317-8ce2-1fd24d52c46a │ └── description Link: https://lkml.kernel.org/r/20250502011246.99238-3-coxu@redhat.com Signed-off-by: Coiby Xu Acked-by: Baoquan He Cc: "Daniel P. Berrange" Cc: Dave Hansen Cc: Dave Young Cc: Jan Pazdziora Cc: Liu Pingfan Cc: Milan Broz Cc: Ondrej Kozina Cc: Vitaly Kuznetsov Signed-off-by: Andrew Morton

kexec: add config option for KHO

2025-05-13T06:50:40Z

We have all generic code in place now to support Kexec with KHO. This patch adds a config option that depends on architecture support to enable KHO support. Link: https://lkml.kernel.org/r/20250509074635.3187114-9-changyuanl@google.com Signed-off-by: Alexander Graf Co-developed-by: Mike Rapoport (Microsoft) Signed-off-by: Mike Rapoport (Microsoft) Signed-off-by: Changyuan Lyu Cc: Andy Lutomirski Cc: Anthony Yznaga Cc: Arnd Bergmann Cc: Ashish Kalra Cc: Ben Herrenschmidt Cc: Borislav Betkov Cc: Catalin Marinas Cc: Dave Hansen Cc: David Woodhouse Cc: Eric Biederman Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: James Gowans Cc: Jason Gunthorpe Cc: Jonathan Corbet Cc: Krzysztof Kozlowski Cc: Marc Rutland Cc: Paolo Bonzini Cc: Pasha Tatashin Cc: Peter Zijlstra Cc: Pratyush Yadav Cc: Rob Herring Cc: Saravana Kannan Cc: Stanislav Kinsburskii Cc: Steven Rostedt Cc: Thomas Gleinxer Cc: Thomas Lendacky Cc: Will Deacon Signed-off-by: Andrew Morton

kexec_file: use SHA-256 library API instead of crypto_shash API

2025-05-12T00:54:12Z

This user of SHA-256 does not support any other algorithm, so the crypto_shash abstraction provides no value. Just use the SHA-256 library API instead, which is much simpler and easier to use. Tested with '/sbin/kexec --kexec-file-syscall'. Link: https://lkml.kernel.org/r/20250428185721.844686-1-ebiggers@kernel.org Signed-off-by: Eric Biggers Cc: Baoquan He Cc: Vivek Goyal Cc: Dave Young Signed-off-by: Andrew Morton

crash, powerpc: default to CRASH_DUMP=n on PPC_BOOK3S_32

2024-11-15T06:43:48Z

Fixes boot failures on 6.9 on PPC_BOOK3S_32 machines using Open Firmware. On these machines, the kernel refuses to boot from non-zero PHYSICAL_START, which occurs when CRASH_DUMP is on. Since most PPC_BOOK3S_32 machines boot via Open Firmware, it should default to off for them. Users booting via some other mechanism can still turn it on explicitly. Does not change the default on any other architectures for the time being. Link: https://lkml.kernel.org/r/20240917163720.1644584-1-dave@vasilevsky.ca Fixes: 75bc255a7444 ("crash: clean up kdump related config items") Signed-off-by: Dave Vasilevsky Reported-by: Reimar Döffinger Closes: https://lists.debian.org/debian-powerpc/2024/07/msg00001.html Acked-by: Michael Ellerman [powerpc] Acked-by: Baoquan He Cc: "Eric W. Biederman" Cc: John Paul Adrian Glaubitz Cc: Reimar Döffinger Cc: Signed-off-by: Andrew Morton

crash: clean up kdump related config items

2024-02-24T01:48:22Z

By splitting CRASH_RESERVE and VMCORE_INFO out from CRASH_CORE, cleaning up the dependency of FA_DMUMP on CRASH_DUMP, and moving crash codes from kexec_core.c to crash_core.c, now we can rearrange CRASH_DUMP to depend on KEXEC_CORE, and make CRASH_DUMP select CRASH_RESERVE and VMCORE_INFO. KEXEC_CORE won't select CRASH_RESERVE and VMCORE_INFO any more because KEXEC_CORE enables codes which allocate control pages, copy kexec/kdump segments, and prepare for switching. These codes are shared by both kexec reboot and crash dumping. Doing this makes codes and the corresponding config items more logical (the right item depends on or is selected by the left item). PROC_KCORE -----------> VMCORE_INFO |----------> VMCORE_INFO FA_DUMP----| |----------> CRASH_RESERVE ---->VMCORE_INFO / |---->CRASH_RESERVE KEXEC --| /| |--> KEXEC_CORE--> CRASH_DUMP-->/-|---->PROC_VMCORE KEXEC_FILE --| \ | \---->CRASH_HOTPLUG KEXEC --| |--> KEXEC_CORE--> kexec reboot KEXEC_FILE --| Link: https://lkml.kernel.org/r/20240124051254.67105-6-bhe@redhat.com Signed-off-by: Baoquan He Cc: Al Viro Cc: Eric W. Biederman Cc: Hari Bathini Cc: Pingfan Liu Cc: Klara Modin Cc: Michael Kelley Cc: Nathan Chancellor Cc: Stephen Rothwell Cc: Yang Li Signed-off-by: Andrew Morton

crash: split vmcoreinfo exporting code out from crash_core.c

2024-02-24T01:48:22Z

Now move the relevant codes into separate files: kernel/crash_reserve.c, include/linux/crash_reserve.h. And add config item CRASH_RESERVE to control its enabling. And also update the old ifdeffery of CONFIG_CRASH_CORE, including of and config item dependency on CRASH_CORE accordingly. And also do renaming as follows: - arch/xxx/kernel/{crash_core.c => vmcore_info.c} because they are only related to vmcoreinfo exporting on x86, arm64, riscv. And also Remove config item CRASH_CORE, and rely on CONFIG_KEXEC_CORE to decide if build in crash_core.c. [yang.lee@linux.alibaba.com: remove duplicated include in vmcore_info.c] Link: https://lkml.kernel.org/r/20240126005744.16561-1-yang.lee@linux.alibaba.com Link: https://lkml.kernel.org/r/20240124051254.67105-3-bhe@redhat.com Signed-off-by: Baoquan He Signed-off-by: Yang Li Acked-by: Hari Bathini Cc: Al Viro Cc: Eric W. Biederman Cc: Pingfan Liu Cc: Klara Modin Cc: Michael Kelley Cc: Nathan Chancellor Cc: Stephen Rothwell Cc: Yang Li Signed-off-by: Andrew Morton