linux/Documentation/admin-guide/kernel-parameters.txt, branch v6.17

x86/vmscape: Enable the mitigation

2025-08-14T17:37:33Z

Enable the previously added mitigation for VMscape. Add the cmdline vmscape={off|ibpb|force} and sysfs reporting. Signed-off-by: Pawan Gupta Signed-off-by: Dave Hansen Reviewed-by: Borislav Petkov (AMD) Reviewed-by: Dave Hansen

Merge tag 'printk-for-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

2025-08-04T17:54:36Z

Pull printk updates from Petr Mladek: - Add new "hash_pointers=[auto|always|never]" boot parameter to force the hashing even with "slab_debug" enabled - Allow to stop CPU, after losing nbcon console ownership during panic(), even without proper NMI - Allow to use the printk kthread immediately even for the 1st registered nbcon - Compiler warning removal * tag 'printk-for-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: printk: nbcon: Allow reacquire during panic printk: Allow to use the printk kthread immediately even for 1st nbcon slab: Decouple slab_debug and no_hash_pointers vsprintf: Use __diag macros to disable '-Wsuggest-attribute=format' compiler-gcc.h: Introduce __diag_GCC_all

Merge tag 'mm-nonmm-stable-2025-08-03-12-47' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-08-03T23:23:09Z

Pull non-MM updates from Andrew Morton: "Significant patch series in this pull request: - "squashfs: Remove page->mapping references" (Matthew Wilcox) gets us closer to being able to remove page->mapping - "relayfs: misc changes" (Jason Xing) does some maintenance and minor feature addition work in relayfs - "kdump: crashkernel reservation from CMA" (Jiri Bohac) switches us from static preallocation of the kdump crashkernel's working memory over to dynamic allocation. So the difficulty of a-priori estimation of the second kernel's needs is removed and the first kernel obtains extra memory - "generalize panic_print's dump function to be used by other kernel parts" (Feng Tang) implements some consolidation and rationalization of the various ways in which a failing kernel splats information at the operator * tag 'mm-nonmm-stable-2025-08-03-12-47' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (80 commits) tools/getdelays: add backward compatibility for taskstats version kho: add test for kexec handover delaytop: enhance error logging and add PSI feature description samples: Kconfig: fix spelling mistake "instancess" -> "instances" fat: fix too many log in fat_chain_add() scripts/spelling.txt: add notifer||notifier to spelling.txt xen/xenbus: fix typo "notifer" net: mvneta: fix typo "notifer" drm/xe: fix typo "notifer" cxl: mce: fix typo "notifer" KVM: x86: fix typo "notifer" MAINTAINERS: add maintainers for delaytop ucount: use atomic_long_try_cmpxchg() in atomic_long_inc_below() ucount: fix atomic_long_inc_below() argument type kexec: enable CMA based contiguous allocation stackdepot: make max number of pools boot-time configurable lib/xxhash: remove unused functions init/Kconfig: restore CONFIG_BROKEN help text lib/raid6: update recov_rvv.c zero page usage docs: update docs after introducing delaytop ...

stackdepot: make max number of pools boot-time configurable

2025-08-02T19:01:38Z

We're hitting the WARN in depot_init_pool() about reaching the stack depot limit because we have long stacks that don't dedup very well. Introduce a new start-up parameter to allow users to set the number of maximum stack depot pools. Link: https://lkml.kernel.org/r/20250718153928.94229-1-matt@readmodwrite.com Signed-off-by: Matt Fleming Acked-by: Vlastimil Babka Acked-by: Marco Elver Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Dmitriy Vyukov Cc: Oscar Salvador Signed-off-by: Andrew Morton

Merge tag 'cgroup-for-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

2025-07-31T23:04:19Z

Pull cgroup updates from Tejun Heo: - Allow css_rstat_updated() in NMI context to enable memory accounting for allocations in NMI context. - /proc/cgroups doesn't contain useful information for cgroup2 and was updated to only show v1 controllers. This unfortunately broke something in the wild. Add an option to bring back the old behavior to ease transition. - selftest updates and other cleanups. * tag 'cgroup-for-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: Add compatibility option for content of /proc/cgroups selftests/cgroup: fix cpu.max tests cgroup: llist: avoid memory tears for llist_node selftests: cgroup: Fix missing newline in test_zswap_writeback_one selftests: cgroup: Allow longer timeout for kmem_dead_cgroups cleanup memcg: cgroup: call css_rstat_updated irrespective of in_nmi() cgroup: remove per-cpu per-subsystem locks cgroup: make css_rstat_updated nmi safe cgroup: support to enable nmi-safe css_rstat_updated selftests: cgroup: Fix compilation on pre-cgroupns kernels selftests: cgroup: Optionally set up v1 environment selftests: cgroup: Add support for named v1 hierarchies in test_core selftests: cgroup_util: Add helpers for testing named v1 hierarchies Documentation: cgroup: add section explaining controller availability cgroup: Drop sock_cgroup_classid() dummy implementation

Merge tag 'integrity-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

2025-07-31T18:42:11Z

Pull integrity update from Mimi Zohar: "A single commit to permit disabling IMA from the boot command line for just the kdump kernel. The exception itself sort of makes sense. My concern is that exceptions do not remain as exceptions, but somehow morph to become the norm" * tag 'integrity-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity: ima: add a knob ima= to allow disabling IMA in kdump kernel

Merge tag 'slab-for-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab

2025-07-30T18:32:38Z

Pull slab updates from Vlastimil Babka: - Convert struct slab to its own flags instead of referencing page flags, which is another preparation step before separating it from struct page completely. Along with that, a bunch of documentation fixes and cleanups (Matthew Wilcox) - Convert large kmalloc to use frozen pages in order to be consistent with non-large kmalloc slabs (Vlastimil Babka) - MAINTAINERS updates (Matthew Wilcox, Lorenzo Stoakes) - Restore NUMA policy support for large kmalloc, broken by mistake in v6.1 (Vlastimil Babka) * tag 'slab-for-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: MAINTAINERS: add missing files to slab section slab: Update MAINTAINERS entry memcg_slabinfo: Fix use of PG_slab kfence: Remove mention of PG_slab vmcoreinfo: Remove documentation of PG_slab and PG_hugetlb doc: Add slab internal kernel-doc slub: Fix a documentation build error for krealloc() slab: Add SL_pfmemalloc flag slab: Add SL_partial flag slab: Rename slab->__page_flags to slab->flags doc: Move SLUB documentation to the admin guide mm, slab: use frozen pages for large kmalloc mm, slab: restore NUMA policy support for large kmalloc

Merge tag 'rcu.release.v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux

2025-07-30T18:01:41Z

Pull RCU updates from Neeraj Upadhyay: "Expedited grace period updates: - Protect against early RCU exp quiescent state reporting during exp grace period initialization - Remove superfluous barrier in task unblock path - Remove the CPU online quiescent state report optimization, which is error prone for certain scenarios - Add warning for unexpected pending requested expedited quiescent state on dying CPU Core: - Robustify rcu_is_cpu_rrupt_from_idle() by using more accurate indicators of the actual context tracking state of a CPU - Handle ->defer_qs_iw_pending field data race - Enable rcu_normal_wake_from_gp by default on systems with <= 16 CPUs - Fix lockup in rcu_read_unlock() due to recursive irq_exit() calls - Refactor expedited handling condition in rcu_read_unlock_special() - Documentation updates for hotplug and GP init scan ordering, separation of rcu_state and rnp's gp_seq states, quiescent state reporting for offline CPUs torture-scripts: - Cleanup and improve scripts : remove superfluous warnings for disabled tests; better handling of kvm.sh --kconfig arg; suppress some confusing diagnostics; tolerate bad kvm.sh args; add new diagnostic for build output; fail allmodconfig testing on warnings - Include RCU_TORTURE_TEST_CHK_RDR_STATE config for KCSAN kernels - Disable default RCU-tasks and clocksource-wdog testing on arm64 - Add EXPERT Kconfig option for arm64 KCSAN runs - Remove SRCU-lite testing rcutorture: - Start torture writer threads creation after reader threads to handle race in SRCU-P scenario - Add SRCU down_read()/up_read() test - Add diagnostics for delayed SRCU up_read(), unmatched up_read(), print number of up/down readers and the number of such readers which migrated to other CPU - Ignore certain unsupported configurations for trivial RCU test - Fix splats in RT kernels due to inaccurate checks for BH-disabled context - Enable checks and logs to capture intentionally exercised unexpected scenarios (too short readers) for BUSTED test - Remove SRCU-lite testing srcu: - Expedite SRCU-fast grace periods - Remove SRCU-lite implementation - Add guards for SRCU-fast readers rcu nocb: - Dump NOCB group leader state on stall detection - Robustify nocb_cb_kthread pointer accesses - Fix delayed execution of hurry callbacks when LAZY_RCU is enabled refscale: - Fix multiplication overflow in "loops" and "nreaders" calculations" * tag 'rcu.release.v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux: (49 commits) rcu: Document concurrent quiescent state reporting for offline CPUs rcu: Document separation of rcu_state and rnp's gp_seq rcu: Document GP init vs hotplug-scan ordering requirements srcu: Add guards for SRCU-fast readers rcu: Fix delayed execution of hurry callbacks rcu: Refactor expedited handling check in rcu_read_unlock_special() checkpatch: Remove SRCU-lite deprecation srcu: Remove SRCU-lite implementation srcu: Expedite SRCU-fast grace periods rcutorture: Remove support for SRCU-lite rcutorture: Remove SRCU-lite scenarios torture: Remove support for SRCU-lite torture: Make torture.sh --allmodconfig testing fail on warnings torture: Add "ERROR" diagnostic for testing kernel-build output torture: Make torture.sh tolerate runs having bad kvm.sh arguments torture: Add textid.txt file to --do-allmodconfig and --do-rcu-rust runs torture: Extract testid.txt generation to separate script torture: Suppress "find" diagnostics from torture.sh --do-none run torture: Provide EXPERT Kconfig option for arm64 KCSAN torture.sh runs rcu: Fix rcu_read_unlock() deadloop due to IRQ work ...

Merge tag 'sched-core-2025-07-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-07-30T00:42:52Z

Pull scheduler updates from Ingo Molnar: "Core scheduler changes: - Better tracking of maximum lag of tasks in presence of different slices duration, for better handling of lag in the fair scheduler (Vincent Guittot) - Clean up and standardize #if/#else/#endif markers throughout the entire scheduler code base (Ingo Molnar) - Make SMP unconditional: build the SMP scheduler's data structures and logic on UP kernel too, even though they are not used, to simplify the scheduler and remove around 200 #ifdef/[#else]/#endif blocks from the scheduler (Ingo Molnar) - Reorganize cgroup bandwidth control interface handling for better interfacing with sched_ext (Tejun Heo) Balancing: - Bump sd->max_newidle_lb_cost when newidle balance fails (Chris Mason) - Remove sched_domain_topology_level::flags to simplify the code (Prateek Nayak) - Simplify and clean up build_sched_topology() (Li Chen) - Optimize build_sched_topology() on large machines (Li Chen) Real-time scheduling: - Add initial version of proxy execution: a mechanism for mutex-owning tasks to inherit the scheduling context of higher priority waiters. Currently limited to a single runqueue and conditional on CONFIG_EXPERT, and other limitations (John Stultz, Peter Zijlstra, Valentin Schneider) - Deadline scheduler (Juri Lelli): - Fix dl_servers initialization order (Juri Lelli) - Fix DL scheduler's root domain reinitialization logic (Juri Lelli) - Fix accounting bugs after global limits change (Juri Lelli) - Fix scalability regression by implementing less agressive dl_server handling (Peter Zijlstra) PSI: - Improve scalability by optimizing psi_group_change() cpu_clock() usage (Peter Zijlstra) Rust changes: - Make Task, CondVar and PollCondVar methods inline to avoid unnecessary function calls (Kunwu Chan, Panagiotis Foliadis) - Add might_sleep() support for Rust code: Rust's "#[track_caller]" mechanism is used so that Rust's might_sleep() doesn't need to be defined as a macro (Fujita Tomonori) - Introduce file_from_location() (Boqun Feng) Debugging & instrumentation: - Make clangd usable with scheduler source code files again (Peter Zijlstra) - tools: Add root_domains_dump.py which dumps root domains info (Juri Lelli) - tools: Add dl_bw_dump.py for printing bandwidth accounting info (Juri Lelli) Misc cleanups & fixes: - Remove play_idle() (Feng Lee) - Fix check_preemption_disabled() (Sebastian Andrzej Siewior) - Do not call __put_task_struct() on RT if pi_blocked_on is set (Luis Claudio R. Goncalves) - Correct the comment in place_entity() (wang wei)" * tag 'sched-core-2025-07-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (84 commits) sched/idle: Remove play_idle() sched: Do not call __put_task_struct() on rt if pi_blocked_on is set sched: Start blocked_on chain processing in find_proxy_task() sched: Fix proxy/current (push,pull)ability sched: Add an initial sketch of the find_proxy_task() function sched: Fix runtime accounting w/ split exec & sched contexts sched: Move update_curr_task logic into update_curr_se locking/mutex: Add p->blocked_on wrappers for correctness checks locking/mutex: Rework task_struct::blocked_on sched: Add CONFIG_SCHED_PROXY_EXEC & boot argument to enable/disable sched/topology: Remove sched_domain_topology_level::flags x86/smpboot: avoid SMT domain attach/destroy if SMT is not enabled x86/smpboot: moves x86_topology to static initialize and truncate x86/smpboot: remove redundant CONFIG_SCHED_SMT smpboot: introduce SDTL_INIT() helper to tidy sched topology setup tools/sched: Add dl_bw_dump.py for printing bandwidth accounting info tools/sched: Add root_domains_dump.py which dumps root domains info sched/deadline: Fix accounting after global limits change sched/deadline: Reset extra_bw to max_bw when clearing root domains sched/deadline: Initialize dl_servers after SMP ...

Merge tag 'x86_bugs_for_v6.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-07-29T23:34:45Z

Pull x86 CPU mitigation updates from Borislav Petkov: - Untangle the Retbleed from the ITS mitigation on Intel. Allow for ITS to enable stuffing independently from Retbleed, do some cleanups to simplify and streamline the code - Simplify SRSO and make mitigation types selection more versatile depending on the Retbleed mitigation selection. Simplify code some - Add the second part of the attack vector controls which provide a lot friendlier user interface to the speculation mitigations than selecting each one by one as it is now. Instead, the selection of whole attack vectors which are relevant to the system in use can be done and protection against only those vectors is enabled, thus giving back some performance to the users * tag 'x86_bugs_for_v6.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (31 commits) x86/bugs: Print enabled attack vectors x86/bugs: Add attack vector controls for TSA x86/pti: Add attack vector controls for PTI x86/bugs: Add attack vector controls for ITS x86/bugs: Add attack vector controls for SRSO x86/bugs: Add attack vector controls for L1TF x86/bugs: Add attack vector controls for spectre_v2 x86/bugs: Add attack vector controls for BHI x86/bugs: Add attack vector controls for spectre_v2_user x86/bugs: Add attack vector controls for retbleed x86/bugs: Add attack vector controls for spectre_v1 x86/bugs: Add attack vector controls for GDS x86/bugs: Add attack vector controls for SRBDS x86/bugs: Add attack vector controls for RFDS x86/bugs: Add attack vector controls for MMIO x86/bugs: Add attack vector controls for TAA x86/bugs: Add attack vector controls for MDS x86/bugs: Define attack vectors relevant for each bug x86/Kconfig: Add arch attack vector support cpu: Define attack vectors ...