Development tree for the kernel CSPRNG https://git.zx2c4.com/linux-rng/atom/include/uapi?h=master 2025-12-03T01:31:22Z 2025-12-03T01:31:22Z Linus Torvalds torvalds@linux-foundation.org 2025-12-03T01:31:22Z urn:sha1:d348c22394ad3c8eaf7bc693cb0ca0edc2ec5246 Pull power management updates from Rafael Wysocki: "There are quite a few interesting things here, including new hardware support, new features, some bug fixes and documentation updates. In addition, there are a usual bunch of minor fixes and cleanups all over. In the new hardware support category, there are intel_pstate and intel_rapl driver updates to support new processors, Panther Lake, Wildcat Lake, Noval Lake, and Diamond Rapids in the OOB mode, OPP and bandwidth allocation support in the tegra186 cpufreq driver, and JH7110S SOC support in dt-platdev cpufreq. The new features are the PM QoS CPU latency limit for suspend-to-idle, the netlink support for the energy model management, support for terminating system suspend via a wakeup event during the sync of file systems, configurable number of hibernation compression threads, the runtime PM auto-cleanup macros, and the "poweroff" PM event that is expected to be used during system shutdown. Bugs are mostly fixed in cpuidle governors, but there are also fixes elsewhere, like in the amd-pstate cpufreq driver. Documentation updates include, but are not limited to, a new doc on debugging shutdown hangs, cross-referencing fixes and cleanups in the intel_pstate documentation, and updates of comments in the core hibernation code. Specifics: - Introduce and document a QoS limit on CPU exit latency during wakeup from suspend-to-idle (Ulf Hansson) - Add support for building libcpupower statically (Zuo An) - Add support for sending netlink notifications to user space on energy model updates (Changwoo Mini, Peng Fan) - Minor improvements to the Rust OPP interface (Tamir Duberstein) - Fixes to scope-based pointers in the OPP library (Viresh Kumar) - Use residency threshold in polling state override decisions in the menu cpuidle governor (Aboorva Devarajan) - Add sanity check for exit latency and target residency in the cpufreq core (Rafael Wysocki) - Use this_cpu_ptr() where possible in the teo governor (Christian Loehle) - Rework the handling of tick wakeups in the teo cpuidle governor to increase the likelihood of stopping the scheduler tick in the cases when tick wakeups can be counted as non-timer ones (Rafael Wysocki) - Fix a reverse condition in the teo cpuidle governor and drop a misguided target residency check from it (Rafael Wysocki) - Clean up multiple minor defects in the teo cpuidle governor (Rafael Wysocki) - Update header inclusion to make it follow the Include What You Use principle (Andy Shevchenko) - Enable MSR-based RAPL PMU support in the intel_rapl power capping driver and arrange for using it on the Panther Lake and Wildcat Lake processors (Kuppuswamy Sathyanarayanan) - Add support for Nova Lake and Wildcat Lake processors to the intel_rapl power capping driver (Kaushlendra Kumar, Srinivas Pandruvada) - Add OPP and bandwidth support for Tegra186 (Aaron Kling) - Optimizations for parameter array handling in the amd-pstate cpufreq driver (Mario Limonciello) - Fix for mode changes with offline CPUs in the amd-pstate cpufreq driver (Gautham Shenoy) - Preserve freq_table_sorted across suspend/hibernate in the cpufreq core (Zihuan Zhang) - Adjust energy model rules for Intel hybrid platforms in the intel_pstate cpufreq driver and improve printing of debug messages in it (Rafael Wysocki) - Replace deprecated strcpy() in cpufreq_unregister_governor() (Thorsten Blum) - Fix duplicate hyperlink target errors in the intel_pstate cpufreq driver documentation and use :ref: directive for internal linking in it (Swaraj Gaikwad, Bagas Sanjaya) - Add Diamond Rapids OOB mode support to the intel_pstate cpufreq driver (Kuppuswamy Sathyanarayanan) - Use mutex guard for driver locking in the intel_pstate driver and eliminate some code duplication from it (Rafael Wysocki) - Replace udelay() with usleep_range() in ACPI cpufreq (Kaushlendra Kumar) - Minor improvements to various cpufreq drivers (Christian Marangi, Hal Feng, Jie Zhan, Marco Crivellari, Miaoqian Lin, and Shuhao Fu) - Replace snprintf() with scnprintf() in show_trace_dev_match() (Kaushlendra Kumar) - Fix memory allocation error handling in pm_vt_switch_required() (Malaya Kumar Rout) - Introduce CALL_PM_OP() macro and use it to simplify code in generic PM operations (Kaushlendra Kumar) - Add module param to backtrace all CPUs in the device power management watchdog (Sergey Senozhatsky) - Rework message printing in swsusp_save() (Rafael Wysocki) - Make it possible to change the number of hibernation compression threads (Xueqin Luo) - Clarify that only cgroup1 freezer uses PM freezer (Tejun Heo) - Add document on debugging shutdown hangs to PM documentation and correct a mistaken configuration option in it (Mario Limonciello) - Shut down wakeup source timer before removing the wakeup source from the list (Kaushlendra Kumar, Rafael Wysocki) - Introduce new PMSG_POWEROFF event for system shutdown handling with the help of PM device callbacks (Mario Limonciello) - Make pm_test delay interruptible by wakeup events (Riwen Lu) - Clean up kernel-doc comment style usage in the core hibernation code and remove unuseful comments from it (Sunday Adelodun, Rafael Wysocki) - Add support for handling wakeup events and aborting the suspend process while it is syncing file systems (Samuel Wu, Rafael Wysocki) - Add WQ_UNBOUND to pm_wq workqueue (Marco Crivellari) - Add runtime PM wrapper macros for ACQUIRE()/ACQUIRE_ERR() and use them in the PCI core and the ACPI TAD driver (Rafael Wysocki) - Improve runtime PM in the ACPI TAD driver (Rafael Wysocki) - Update pm_runtime_allow/forbid() documentation (Rafael Wysocki) - Fix typos in runtime.c comments (Malaya Kumar Rout) - Move governor.h from devfreq under include/linux/ and rename to devfreq-governor.h to allow devfreq governor definitions in out of drivers/devfreq/ (Dmitry Baryshkov) - Use min() to improve readability in tegra30-devfreq.c (Thorsten Blum) - Fix potential use-after-free issue of OPP handling in hisi_uncore_freq.c (Pengjie Zhang) - Fix typo in DFSO_DOWNDIFFERENTIAL macro name in governor_simpleondemand.c in devfreq (Riwen Lu)" * tag 'pm-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (96 commits) PM / devfreq: Fix typo in DFSO_DOWNDIFFERENTIAL macro name cpuidle: Warn instead of bailing out if target residency check fails cpuidle: Update header inclusion Documentation: power/cpuidle: Document the CPU system wakeup latency QoS cpuidle: Respect the CPU system wakeup QoS limit for cpuidle sched: idle: Respect the CPU system wakeup QoS limit for s2idle pmdomain: Respect the CPU system wakeup QoS limit for cpuidle pmdomain: Respect the CPU system wakeup QoS limit for s2idle PM: QoS: Introduce a CPU system wakeup QoS limit cpuidle: governors: teo: Add missing space to the description PM: hibernate: Extra cleanup of comments in swap handling code PM / devfreq: tegra30: use min to simplify actmon_cpu_to_emc_rate PM / devfreq: hisi: Fix potential UAF in OPP handling PM / devfreq: Move governor.h to a public header location powercap: intel_rapl: Enable MSR-based RAPL PMU support powercap: intel_rapl: Prepare read_raw() interface for atomic-context callers cpufreq: qcom-nvmem: fix compilation warning for qcom_cpufreq_ipq806x_match_list PM: sleep: Call pm_sleep_fs_sync() instead of ksys_sync_helper() PM: sleep: Add support for wakeup during filesystem sync cpufreq: ACPI: Replace udelay() with usleep_range() ... 2025-12-03T01:03:55Z Linus Torvalds torvalds@linux-foundation.org 2025-12-03T01:03:55Z urn:sha1:44fc84337b6eae580a51cf6f7ca6a22ef1349556 Pull arm64 updates from Catalin Marinas: "These are the arm64 updates for 6.19. The biggest part is the Arm MPAM driver under drivers/resctrl/. There's a patch touching mm/ to handle spurious faults for huge pmd (similar to the pte version). The corresponding arm64 part allows us to avoid the TLB maintenance if a (huge) page is reused after a write fault. There's EFI refactoring to allow runtime services with preemption enabled and the rest is the usual perf/PMU updates and several cleanups/typos. Summary: Core features: - Basic Arm MPAM (Memory system resource Partitioning And Monitoring) driver under drivers/resctrl/ which makes use of the fs/rectrl/ API Perf and PMU: - Avoid cycle counter on multi-threaded CPUs - Extend CSPMU device probing and add additional filtering support for NVIDIA implementations - Add support for the PMUs on the NoC S3 interconnect - Add additional compatible strings for new Cortex and C1 CPUs - Add support for data source filtering to the SPE driver - Add support for i.MX8QM and "DB" PMU in the imx PMU driver Memory managemennt: - Avoid broadcast TLBI if page reused in write fault - Elide TLB invalidation if the old PTE was not valid - Drop redundant cpu_set_*_tcr_t0sz() macros - Propagate pgtable_alloc() errors outside of __create_pgd_mapping() - Propagate return value from __change_memory_common() ACPI and EFI: - Call EFI runtime services without disabling preemption - Remove unused ACPI function Miscellaneous: - ptrace support to disable streaming on SME-only systems - Improve sysreg generation to include a 'Prefix' descriptor - Replace __ASSEMBLY__ with __ASSEMBLER__ - Align register dumps in the kselftest zt-test - Remove some no longer used macros/functions - Various spelling corrections" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (94 commits) arm64/mm: Document why linear map split failure upon vm_reset_perms is not problematic arm64/pageattr: Propagate return value from __change_memory_common arm64/sysreg: Remove unused define ARM64_FEATURE_FIELD_BITS KVM: arm64: selftests: Consider all 7 possible levels of cache KVM: arm64: selftests: Remove ARM64_FEATURE_FIELD_BITS and its last user arm64: atomics: lse: Remove unused parameters from ATOMIC_FETCH_OP_AND macros Documentation/arm64: Fix the typo of register names ACPI: GTDT: Get rid of acpi_arch_timer_mem_init() perf: arm_spe: Add support for filtering on data source perf: Add perf_event_attr::config4 perf/imx_ddr: Add support for PMU in DB (system interconnects) perf/imx_ddr: Get and enable optional clks perf/imx_ddr: Move ida_alloc() from ddr_perf_init() to ddr_perf_probe() dt-bindings: perf: fsl-imx-ddr: Add compatible string for i.MX8QM, i.MX8QXP and i.MX8DXL arm64: remove duplicate ARCH_HAS_MEM_ENCRYPT arm64: mm: use untagged address to calculate page index MAINTAINERS: new entry for MPAM Driver arm_mpam: Add kunit tests for props_mismatch() arm_mpam: Add kunit test for bitmap reset arm_mpam: Add helper to reset saved mbwu state ... 2025-12-02T16:48:53Z Linus Torvalds torvalds@linux-foundation.org 2025-12-02T16:48:53Z urn:sha1:2b09f480f0a1e68111ae36a7be9aa1c93e067255 Pull rseq updates from Thomas Gleixner: "A large overhaul of the restartable sequences and CID management: The recent enablement of RSEQ in glibc resulted in regressions which are caused by the related overhead. It turned out that the decision to invoke the exit to user work was not really a decision. More or less each context switch caused that. There is a long list of small issues which sums up nicely and results in a 3-4% regression in I/O benchmarks. The other detail which caused issues due to extra work in context switch and task migration is the CID (memory context ID) management. It also requires to use a task work to consolidate the CID space, which is executed in the context of an arbitrary task and results in sporadic uncontrolled exit latencies. The rewrite addresses this by: - Removing deprecated and long unsupported functionality - Moving the related data into dedicated data structures which are optimized for fast path processing. - Caching values so actual decisions can be made - Replacing the current implementation with a optimized inlined variant. - Separating fast and slow path for architectures which use the generic entry code, so that only fault and error handling goes into the TIF_NOTIFY_RESUME handler. - Rewriting the CID management so that it becomes mostly invisible in the context switch path. That moves the work of switching modes into the fork/exit path, which is a reasonable tradeoff. That work is only required when a process creates more threads than the cpuset it is allowed to run on or when enough threads exit after that. An artificial thread pool benchmarks which triggers this did not degrade, it actually improved significantly. The main effect in migration heavy scenarios is that runqueue lock held time and therefore contention goes down significantly" * tag 'core-rseq-2025-11-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (54 commits) sched/mmcid: Switch over to the new mechanism sched/mmcid: Implement deferred mode change irqwork: Move data struct to a types header sched/mmcid: Provide CID ownership mode fixup functions sched/mmcid: Provide new scheduler CID mechanism sched/mmcid: Introduce per task/CPU ownership infrastructure sched/mmcid: Serialize sched_mm_cid_fork()/exit() with a mutex sched/mmcid: Provide precomputed maximal value sched/mmcid: Move initialization out of line signal: Move MMCID exit out of sighand lock sched/mmcid: Convert mm CID mask to a bitmap cpumask: Cache num_possible_cpus() sched/mmcid: Use cpumask_weighted_or() cpumask: Introduce cpumask_weighted_or() sched/mmcid: Prevent pointless work in mm_update_cpus_allowed() sched/mmcid: Move scheduler code out of global header sched: Fixup whitespace damage sched/mmcid: Cacheline align MM CID storage sched/mmcid: Use proper data structures sched/mmcid: Revert the complex CID management ... 2025-12-02T04:42:01Z Linus Torvalds torvalds@linux-foundation.org 2025-12-02T04:42:01Z urn:sha1:6c26fbe8c9d3e932dce6afe2505b19b4b261cae9 Pull performance events updates from Ingo Molnar: "Callchain support: - Add support for deferred user-space stack unwinding for perf, enabled on x86. (Peter Zijlstra, Steven Rostedt) - unwind_user/x86: Enable frame pointer unwinding on x86 (Josh Poimboeuf) x86 PMU support and infrastructure: - x86/insn: Simplify for_each_insn_prefix() (Peter Zijlstra) - x86/insn,uprobes,alternative: Unify insn_is_nop() (Peter Zijlstra) Intel PMU driver: - Large series to prepare for and implement architectural PEBS support for Intel platforms such as Clearwater Forest (CWF) and Panther Lake (PTL). (Dapeng Mi, Kan Liang) - Check dynamic constraints (Kan Liang) - Optimize PEBS extended config (Peter Zijlstra) - cstates: - Remove PC3 support from LunarLake (Zhang Rui) - Add Pantherlake support (Zhang Rui) - Clearwater Forest support (Zide Chen) AMD PMU driver: - x86/amd: Check event before enable to avoid GPF (George Kennedy) Fixes and cleanups: - task_work: Fix NMI race condition (Peter Zijlstra) - perf/x86: Fix NULL event access and potential PEBS record loss (Dapeng Mi) - Misc other fixes and cleanups (Dapeng Mi, Ingo Molnar, Peter Zijlstra)" * tag 'perf-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (38 commits) perf/x86/intel: Fix and clean up intel_pmu_drain_arch_pebs() type use perf/x86/intel: Optimize PEBS extended config perf/x86/intel: Check PEBS dyn_constraints perf/x86/intel: Add a check for dynamic constraints perf/x86/intel: Add counter group support for arch-PEBS perf/x86/intel: Setup PEBS data configuration and enable legacy groups perf/x86/intel: Update dyn_constraint base on PEBS event precise level perf/x86/intel: Allocate arch-PEBS buffer and initialize PEBS_BASE MSR perf/x86/intel: Process arch-PEBS records or record fragments perf/x86/intel/ds: Factor out PEBS group processing code to functions perf/x86/intel/ds: Factor out PEBS record processing code to functions perf/x86/intel: Initialize architectural PEBS perf/x86/intel: Correct large PEBS flag check perf/x86/intel: Replace x86_pmu.drain_pebs calling with static call perf/x86: Fix NULL event access and potential PEBS record loss perf/x86: Remove redundant is_x86_event() prototype entry,unwind/deferred: Fix unwind_reset_info() placement unwind_user/x86: Fix arch=um build perf: Support deferred user unwind unwind_user/x86: Teach FP unwind about start of function ... 2025-12-01T23:34:41Z Linus Torvalds torvalds@linux-foundation.org 2025-12-01T23:34:41Z urn:sha1:db74a7d02ae244ec0552d18f51054f9ae0d921ad Pull directory delegations update from Christian Brauner: "This contains the work for recall-only directory delegations for knfsd. Add support for simple, recallable-only directory delegations. This was decided at the fall NFS Bakeathon where the NFS client and server maintainers discussed how to merge directory delegation support. The approach starts with recallable-only delegations for several reasons: 1. RFC8881 has gaps that are being addressed in RFC8881bis. In particular, it requires directory position information for CB_NOTIFY callbacks, which is difficult to implement properly under Linux. The spec is being extended to allow that information to be omitted. 2. Client-side support for CB_NOTIFY still lags. The client side involves heuristics about when to request a delegation. 3. Early indication shows simple, recallable-only delegations can help performance. Anna Schumaker mentioned seeing a multi-minute speedup in xfstests runs with them enabled. With these changes, userspace can also request a read lease on a directory that will be recalled on conflicting accesses. This may be useful for applications like Samba. Users can disable leases altogether via the fs.leases-enable sysctl if needed. VFS changes: - Dedicated Type for Delegations Introduce struct delegated_inode to track inodes that may have delegations that need to be broken. This replaces the previous approach of passing raw inode pointers through the delegation breaking code paths, providing better type safety and clearer semantics for the delegation machinery. - Break parent directory delegations in open(..., O_CREAT) codepath - Allow mkdir to wait for delegation break on parent - Allow rmdir to wait for delegation break on parent - Add try_break_deleg calls for parents to vfs_link(), vfs_rename(), and vfs_unlink() - Make vfs_create(), vfs_mknod(), and vfs_symlink() break delegations on parent directory - Clean up argument list for vfs_create() - Expose delegation support to userland Filelock changes: - Make lease_alloc() take a flags argument - Rework the __break_lease API to use flags - Add struct delegated_inode - Push the S_ISREG check down to ->setlease handlers - Lift the ban on directory leases in generic_setlease NFSD changes: - Allow filecache to hold S_IFDIR files - Allow DELEGRETURN on directories - Wire up GET_DIR_DELEGATION handling Fixes: - Fix kernel-doc warnings in __fcntl_getlease - Add needed headers for new struct delegation definition" * tag 'vfs-6.19-rc1.directory.delegations' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: vfs: add needed headers for new struct delegation definition filelock: __fcntl_getlease: fix kernel-doc warnings vfs: expose delegation support to userland nfsd: wire up GET_DIR_DELEGATION handling nfsd: allow DELEGRETURN on directories nfsd: allow filecache to hold S_IFDIR files filelock: lift the ban on directory leases in generic_setlease vfs: make vfs_symlink break delegations on parent dir vfs: make vfs_mknod break delegations on parent directory vfs: make vfs_create break delegations on parent directory vfs: clean up argument list for vfs_create() vfs: break parent dir delegations in open(..., O_CREAT) codepath vfs: allow rmdir to wait for delegation break on parent vfs: allow mkdir to wait for delegation break on parent vfs: add try_break_deleg calls for parents to vfs_{link,rename,unlink} filelock: push the S_ISREG check down to ->setlease handlers filelock: add struct delegated_inode filelock: rework the __break_lease API to use flags filelock: make lease_alloc() take a flags argument 2025-12-01T18:26:38Z Linus Torvalds torvalds@linux-foundation.org 2025-12-01T18:26:38Z urn:sha1:f2e74ecfba1b0d407f04b671a240cc65e309e529 Pull folio updates from Christian Brauner: "Add a new folio_next_pos() helper function that returns the file position of the first byte after the current folio. This is a common operation in filesystems when needing to know the end of the current folio. The helper is lifted from btrfs which already had its own version, and is now used across multiple filesystems and subsystems: - btrfs - buffer - ext4 - f2fs - gfs2 - iomap - netfs - xfs - mm This fixes a long-standing bug in ocfs2 on 32-bit systems with files larger than 2GiB. Presumably this is not a common configuration, but the fix is backported anyway. The other filesystems did not have bugs, they were just mildly inefficient. This also introduce uoff_t as the unsigned version of loff_t. A recent commit inadvertently changed a comparison from being unsigned (on 64-bit systems) to being signed (which it had always been on 32-bit systems), leading to sporadic fstests failures. Generally file sizes are restricted to being a signed integer, but in places where -1 is passed to indicate "up to the end of the file", it is convenient to have an unsigned type to ensure comparisons are always unsigned regardless of architecture" * tag 'vfs-6.19-rc1.folio' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: fs: Add uoff_t mm: Use folio_next_pos() xfs: Use folio_next_pos() netfs: Use folio_next_pos() iomap: Use folio_next_pos() gfs2: Use folio_next_pos() f2fs: Use folio_next_pos() ext4: Use folio_next_pos() buffer: Use folio_next_pos() btrfs: Use folio_next_pos() filemap: Add folio_next_pos() 2025-12-01T18:17:39Z Linus Torvalds torvalds@linux-foundation.org 2025-12-01T18:17:39Z urn:sha1:212c4053a1502e5117d8cbbbd1c15579ce1839bb Pull pidfd and coredump updates from Christian Brauner: "Features: - Expose coredump signal via pidfd Expose the signal that caused the coredump through the pidfd interface. The recent changes to rework coredump handling to rely on unix sockets are in the process of being used in systemd. The previous systemd coredump container interface requires the coredump file descriptor and basic information including the signal number to be sent to the container. This means the signal number needs to be available before sending the coredump to the container. - Add supported_mask field to pidfd Add a new supported_mask field to struct pidfd_info that indicates which information fields are supported by the running kernel. This allows userspace to detect feature availability without relying on error codes or kernel version checks. Cleanups: - Drop struct pidfs_exit_info and prepare to drop exit_info pointer, simplifying the internal publication mechanism for exit and coredump information retrievable via the pidfd ioctl - Use guard() for task_lock in pidfs - Reduce wait_pidfd lock scope - Add missing PIDFD_INFO_SIZE_VER1 constant - Add missing BUILD_BUG_ON() assert on struct pidfd_info Fixes: - Fix PIDFD_INFO_COREDUMP handling Selftests: - Split out coredump socket tests and common helpers into separate files for better organization - Fix userspace coredump client detection issues - Handle edge-triggered epoll correctly - Ignore ENOSPC errors in tests - Add debug logging to coredump socket tests, socket protocol tests, and test helpers - Add tests for PIDFD_INFO_COREDUMP_SIGNAL - Add tests for supported_mask field - Update pidfd header for selftests" * tag 'vfs-6.19-rc1.coredump' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (23 commits) pidfs: reduce wait_pidfd lock scope selftests/coredump: add second PIDFD_INFO_COREDUMP_SIGNAL test selftests/coredump: add first PIDFD_INFO_COREDUMP_SIGNAL test selftests/coredump: ignore ENOSPC errors selftests/coredump: add debug logging to coredump socket protocol tests selftests/coredump: add debug logging to coredump socket tests selftests/coredump: add debug logging to test helpers selftests/coredump: handle edge-triggered epoll correctly selftests/coredump: fix userspace coredump client detection selftests/coredump: fix userspace client detection selftests/coredump: split out coredump socket tests selftests/coredump: split out common helpers selftests/pidfd: add second supported_mask test selftests/pidfd: add first supported_mask test selftests/pidfd: update pidfd header pidfs: expose coredump signal pidfs: drop struct pidfs_exit_info pidfs: prepare to drop exit_info pointer pidfd: add a new supported_mask field pidfs: add missing BUILD_BUG_ON() assert on struct pidfd_info ... 2025-12-01T17:47:41Z Linus Torvalds torvalds@linux-foundation.org 2025-12-01T17:47:41Z urn:sha1:415d34b92c1f921a9ff3c38f56319cbc5536f642 Pull namespace updates from Christian Brauner: "This contains substantial namespace infrastructure changes including a new system call, active reference counting, and extensive header cleanups. The branch depends on the shared kbuild branch for -fms-extensions support. Features: - listns() system call Add a new listns() system call that allows userspace to iterate through namespaces in the system. This provides a programmatic interface to discover and inspect namespaces, addressing longstanding limitations: Currently, there is no direct way for userspace to enumerate namespaces. Applications must resort to scanning /proc/*/ns/ across all processes, which is: - Inefficient - requires iterating over all processes - Incomplete - misses namespaces not attached to any running process but kept alive by file descriptors, bind mounts, or parent references - Permission-heavy - requires access to /proc for many processes - No ordering or ownership information - No filtering per namespace type The listns() system call solves these problems: ssize_t listns(const struct ns_id_req *req, u64 *ns_ids, size_t nr_ns_ids, unsigned int flags); struct ns_id_req { __u32 size; __u32 spare; __u64 ns_id; struct /* listns */ { __u32 ns_type; __u32 spare2; __u64 user_ns_id; }; }; Features include: - Pagination support for large namespace sets - Filtering by namespace type (MNT_NS, NET_NS, USER_NS, etc.) - Filtering by owning user namespace - Permission checks respecting namespace isolation - Active Reference Counting Introduce an active reference count that tracks namespace visibility to userspace. A namespace is visible in the following cases: - The namespace is in use by a task - The namespace is persisted through a VFS object (namespace file descriptor or bind-mount) - The namespace is a hierarchical type and is the parent of child namespaces The active reference count does not regulate lifetime (that's still done by the normal reference count) - it only regulates visibility to namespace file handles and listns(). This prevents resurrection of namespaces that are pinned only for internal kernel reasons (e.g., user namespaces held by file->f_cred, lazy TLB references on idle CPUs, etc.) which should not be accessible via (1)-(3). - Unified Namespace Tree Introduce a unified tree structure for all namespaces with: - Fixed IDs assigned to initial namespaces - Lookup based solely on inode number - Maintained list of owned namespaces per user namespace - Simplified rbtree comparison helpers Cleanups - Header Reorganization: - Move namespace types into separate header (ns_common_types.h) - Decouple nstree from ns_common header - Move nstree types into separate header - Switch to new ns_tree_{node,root} structures with helper functions - Use guards for ns_tree_lock - Initial Namespace Reference Count Optimization - Make all reference counts on initial namespaces a nop to avoid pointless cacheline ping-pong for namespaces that can never go away - Drop custom reference count initialization for initial namespaces - Add NS_COMMON_INIT() macro and use it for all namespaces - pid: rely on common reference count behavior - Miscellaneous Cleanups - Rename exit_task_namespaces() to exit_nsproxy_namespaces() - Rename is_initial_namespace() and make argument const - Use boolean to indicate anonymous mount namespace - Simplify owner list iteration in nstree - nsfs: raise SB_I_NODEV, SB_I_NOEXEC, and DCACHE_DONTCACHE explicitly - nsfs: use inode_just_drop() - pidfs: raise DCACHE_DONTCACHE explicitly - pidfs: simplify PIDFD_GET__NAMESPACE ioctls - libfs: allow to specify s_d_flags - cgroup: add cgroup namespace to tree after owner is set - nsproxy: fix free_nsproxy() and simplify create_new_namespaces() Fixes: - setns(pidfd, ...) race condition Fix a subtle race when using pidfds with setns(). When the target task exits after prepare_nsset() but before commit_nsset(), the namespace's active reference count might have been dropped. If setns() then installs the namespaces, it would bump the active reference count from zero without taking the required reference on the owner namespace, leading to underflow when later decremented. The fix resurrects the ownership chain if necessary - if the caller succeeded in grabbing passive references, the setns() should succeed even if the target task exits or gets reaped. - Return EFAULT on put_user() error instead of success - Make sure references are dropped outside of RCU lock (some namespaces like mount namespace sleep when putting the last reference) - Don't skip active reference count initialization for network namespace - Add asserts for active refcount underflow - Add asserts for initial namespace reference counts (both passive and active) - ipc: enable is_ns_init_id() assertions - Fix kernel-doc comments for internal nstree functions - Selftests - 15 active reference count tests - 9 listns() functionality tests - 7 listns() permission tests - 12 inactive namespace resurrection tests - 3 threaded active reference count tests - commit_creds() active reference tests - Pagination and stress tests - EFAULT handling test - nsid tests fixes" * tag 'namespace-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (103 commits) pidfs: simplify PIDFD_GET_<type>_NAMESPACE ioctls nstree: fix kernel-doc comments for internal functions nsproxy: fix free_nsproxy() and simplify create_new_namespaces() selftests/namespaces: fix nsid tests ns: drop custom reference count initialization for initial namespaces pid: rely on common reference count behavior ns: add asserts for initial namespace active reference counts ns: add asserts for initial namespace reference counts ns: make all reference counts on initial namespace a nop ipc: enable is_ns_init_id() assertions fs: use boolean to indicate anonymous mount namespace ns: rename is_initial_namespace() ns: make is_initial_namespace() argument const nstree: use guards for ns_tree_lock nstree: simplify owner list iteration nstree: switch to new structures nstree: add helper to operate on struct ns_tree_{node,root} nstree: move nstree types into separate header nstree: decouple from ns_common header ns: move namespace types into separate header ... 2025-11-28T15:44:00Z Rafael J. Wysocki rafael.j.wysocki@intel.com 2025-11-28T15:44:00Z urn:sha1:638757c9c9e5a823671367150a9f48e93d115b48 Merge energy model management updates and operating performance points (OPP) library changes for 6.19-rc1: - Add support for sending netlink notifications to user space on energy model updates (Changwoo Mini, Peng Fan) - Minor improvements to the Rust OPP interface (Tamir Duberstein) - Fixes to scope-based pointers in the OPP library (Viresh Kumar) * pm-em: PM: EM: Add to em_pd_list only when no failure PM: EM: Notify an event when the performance domain changes PM: EM: Implement em_notify_pd_created/updated() PM: EM: Implement em_notify_pd_deleted() PM: EM: Implement em_nl_get_pd_table_doit() PM: EM: Implement em_nl_get_pds_doit() PM: EM: Add an iterator and accessor for the performance domain PM: EM: Add a skeleton code for netlink notification PM: EM: Add em.yaml and autogen files PM: EM: Expose the ID of a performance domain via debugfs PM: EM: Assign a unique ID when creating a performance domain * pm-opp: rust: opp: simplify callers of `to_c_str_array` OPP: Initialize scope-based pointers inline rust: opp: fix broken rustdoc link 2025-11-28T09:55:34Z Jeff Layton jlayton@kernel.org 2025-11-28T09:55:09Z urn:sha1:4be9e04ebf75a5c4478c1c6295e2122e5dc98f5f The definition of struct delegation uses stdint.h integer types. Add the necessary headers to ensure that always works. Fixes: 1602bad16d7d ("vfs: expose delegation support to userland") Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>