kernel/linux.git/Documentation/admin-guide, branch v6.18.34

Documentation: intel_pstate: Fix description of asymmetric packing with SMT

2026-06-01T15:50:59+00:00

[ Upstream commit ee047fc7a2da90554410128195058c409a391d43 ] Patchset [1], including commits 046a5a95c3b0 ("x86/sched/itmt: Give all SMT siblings of a core the same priority") 995998ebdebd ("x86/sched: Remove SD_ASYM_PACKING from the SMT domain flags") overhauled asym_packing handling in the scheduler on x86 hybrid processors with SMT. It removed SD_ASYM_PACKING from the x86 SMT scheduling domain and made all SMT siblings of a core share the same priority. As a result, asym_packing operates only across physical cores, spreading tasks among them and only using idle SMT siblings once all physical cores are busy. Fix the documentation to reflect this behavior. Fixes: f20af84c29b2 ("cpufreq: intel_pstate: Document hybrid processor support") Link: https://lore.kernel.org/r/20230406203148.19182-1-ricardo.neri-calderon@linux.intel.com [1] Signed-off-by: Ricardo Neri [ rjw: Changelog edits ] Link: https://patch.msgid.link/20260424-rneri-fix-intel-pstate-doc-smt-asym-packing-v1-1-317bf7d5c362@linux.intel.com Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

Docs/admin-guide/mm/damon/reclaim: warn commit_inputs vs param updates race

2026-04-22T11:22:28+00:00

commit 0beba407d4585a15b0dc09f2064b5b3ddcb0e857 upstream. Patch series "Docs/admin-guide/mm/damon: warn commit_inputs vs other params race". Writing 'Y' to the commit_inputs parameter of DAMON_RECLAIM and DAMON_LRU_SORT, and writing other parameters before the commit_inputs request is completely processed can cause race conditions. While the consequence can be bad, the documentation is not clearly describing that. Add clear warnings. The issue was discovered [1,2] by sashiko. This patch (of 2): DAMON_RECLAIM handles commit_inputs request inside kdamond thread, reading the module parameters. If the user updates the module parameters while the kdamond thread is reading those, races can happen. To avoid this, the commit_inputs parameter shows whether it is still in the progress, assuming users wouldn't update parameters in the middle of the work. Some users might ignore that. Add a warning about the behavior. The issue was discovered in [1] by sashiko. Link: https://lore.kernel.org/20260329153052.46657-2-sj@kernel.org Link: https://lore.kernel.org/20260319161620.189392-3-objecting@objecting.org [1] Link: https://lore.kernel.org/20260319161620.189392-2-objecting@objecting.org [3] Fixes: 81a84182c343 ("Docs/admin-guide/mm/damon/reclaim: document 'commit_inputs' parameter") Signed-off-by: SeongJae Park Cc: # 5.19.x Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

usb: core: new quirk to handle devices with zero configurations

2026-04-02T11:23:01+00:00

[ Upstream commit 9f6a983cfa22ac662c86e60816d3a357d4b551e9 ] Some USB devices incorrectly report bNumConfigurations as 0 in their device descriptor, which causes the USB core to reject them during enumeration. logs: usb 1-2: device descriptor read/64, error -71 usb 1-2: no configurations usb 1-2: can't read configurations, error -22 However, these devices actually work correctly when treated as having a single configuration. Add a new quirk USB_QUIRK_FORCE_ONE_CONFIG to handle such devices. When this quirk is set, assume the device has 1 configuration instead of failing with -EINVAL. This quirk is applied to the device with VID:PID 5131:2007 which exhibits this behavior. Signed-off-by: Jie Deng Link: https://patch.msgid.link/20260227084931.1527461-1-dengjie03@kylinos.cn Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

cgroup/cpuset: Don't fail cpuset.cpus change in v2

2026-03-04T12:19:56+00:00

[ Upstream commit 6e6f13f6d5095f3a432da421e78f4d7d51ef39c8 ] Commit fe8cd2736e75 ("cgroup/cpuset: Delay setting of CS_CPU_EXCLUSIVE until valid partition") introduced a new check to disallow the setting of a new cpuset.cpus.exclusive value that is a superset of a sibling's cpuset.cpus value so that there will at least be one CPU left in the sibling in case the cpuset becomes a valid partition root. This new check does have the side effect of failing a cpuset.cpus change that make it a subset of a sibling's cpuset.cpus.exclusive value. With v2, users are supposed to be allowed to set whatever value they want in cpuset.cpus without failure. To maintain this rule, the check is now restricted to only when cpuset.cpus.exclusive is being changed not when cpuset.cpus is changed. The cgroup-v2.rst doc file is also updated to reflect this change. Signed-off-by: Waiman Long Reviewed-by: Chen Ridong Signed-off-by: Tejun Heo Signed-off-by: Sasha Levin

smack: fix bug: setting task label silently ignores input garbage

2025-12-18T13:02:25+00:00

[ Upstream commit 674e2b24791cbe8fd5dc8a0aed4cb4404fcd2028 ] This command: # echo foo/bar >/proc/$$/attr/smack/current gives the task a label 'foo' w/o indication that label does not match input. Setting the label with lsm_set_self_attr() syscall behaves identically. This occures because: 1) smk_parse_smack() is used to convert input to a label 2) smk_parse_smack() takes only that part from the beginning of the input that looks like a label. 3) `/' is prohibited in labels, so only "foo" is taken. (2) is by design, because smk_parse_smack() is used for parsing strings which are more than just a label. Silent failure is not a good thing, and there are two indicators that this was not done intentionally: (size >= SMK_LONGLABEL) ~> invalid clause at the beginning of the do_setattr() and the "Returns the length of the smack label" claim in the do_setattr() description. So I fixed this by adding one tiny check: the taken label length == input length. Since input length is now strictly controlled, I changed the two ways of setting label smack_setselfattr(): lsm_set_self_attr() syscall smack_setprocattr(): > /proc/.../current to accommodate the divergence in what they understand by "input length": smack_setselfattr counts mandatory \0 into input length, smack_setprocattr does not. smack_setprocattr allows various trailers after label Related changes: * fixed description for smk_parse_smack * allow unprivileged tasks validate label syntax. * extract smk_parse_label_len() from smk_parse_smack() so parsing may be done w/o string allocation. * extract smk_import_valid_label() from smk_import_entry() to avoid repeated parsing. * smk_parse_smack(): scan null-terminated strings for no more than SMK_LONGLABEL(256) characters * smack_setselfattr(): require struct lsm_ctx . flags == 0 to reserve them for future. Fixes: e114e473771c ("Smack: Simplified Mandatory Access Control Kernel") Signed-off-by: Konstantin Andreev Signed-off-by: Casey Schaufler Signed-off-by: Sasha Levin

smack: fix bug: invalid label of unix socket file

2025-12-18T13:02:25+00:00

[ Upstream commit 78fc6a94be252b27bb73e4926eed70b5e302a8e0 ] According to [1], the label of a UNIX domain socket (UDS) file (i.e., the filesystem object representing the socket) is not supposed to participate in Smack security. To achieve this, [1] labels UDS files with "*" in smack_d_instantiate(). Before [2], smack_d_instantiate() was responsible for initializing Smack security for all inodes, except ones under /proc [2] imposed the sole responsibility for initializing inode security for newly created filesystem objects on smack_inode_init_security(). However, smack_inode_init_security() lacks some logic present in smack_d_instantiate(). In particular, it does not label UDS files with "*". This patch adds the missing labeling of UDS files with "*" to smack_inode_init_security(). Labeling UDS files with "*" in smack_d_instantiate() still works for stale UDS files that already exist on disk. Stale UDS files are useless, but I keep labeling them for consistency and maybe to make easier for user to delete them. Compared to [1], this version introduces the following improvements: * UDS file label is held inside inode only and not saved to xattrs. * relabeling UDS files (setxattr, removexattr, etc.) is blocked. [1] 2010-11-24 Casey Schaufler commit b4e0d5f0791b ("Smack: UDS revision") [2] 2023-11-16 roberto.sassu Fixes: e63d86b8b764 ("smack: Initialize the in-memory inode in smack_inode_init_security()") Link: https://lore.kernel.org/linux-security-module/20231116090125.187209-5-roberto.sassu@huaweicloud.com/ Signed-off-by: Konstantin Andreev Signed-off-by: Casey Schaufler Signed-off-by: Sasha Levin

Merge tag 'x86_core_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-10-11T18:19:16+00:00

Pull more x86 updates from Borislav Petkov: - Remove a bunch of asm implementing condition flags testing in KVM's emulator in favor of int3_emulate_jcc() which is written in C - Replace KVM fastops with C-based stubs which avoids problems with the fastop infra related to latter not adhering to the C ABI due to their special calling convention and, more importantly, bypassing compiler control-flow integrity checking because they're written in asm - Remove wrongly used static branches and other ugliness accumulated over time in hyperv's hypercall implementation with a proper static function call to the correct hypervisor call variant - Add some fixes and modifications to allow running FRED-enabled kernels in KVM even on non-FRED hardware - Add kCFI improvements like validating indirect calls and prepare for enabling kCFI with GCC. Add cmdline params documentation and other code cleanups - Use the single-byte 0xd6 insn as the official #UD single-byte undefined opcode instruction as agreed upon by both x86 vendors - Other smaller cleanups and touchups all over the place * tag 'x86_core_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits) x86,retpoline: Optimize patch_retpoline() x86,ibt: Use UDB instead of 0xEA x86/cfi: Remove __noinitretpoline and __noretpoline x86/cfi: Add "debug" option to "cfi=" bootparam x86/cfi: Standardize on common "CFI:" prefix for CFI reports x86/cfi: Document the "cfi=" bootparam options x86/traps: Clarify KCFI instruction layout compiler_types.h: Move __nocfi out of compiler-specific header objtool: Validate kCFI calls x86/fred: KVM: VMX: Always use FRED for IRQs when CONFIG_X86_FRED=y x86/fred: Play nice with invoking asm_fred_entry_from_kvm() on non-FRED hardware x86/fred: Install system vector handlers even if FRED isn't fully enabled x86/hyperv: Use direct call to hypercall-page x86/hyperv: Clean up hv_do_hypercall() KVM: x86: Remove fastops KVM: x86: Convert em_salc() to C KVM: x86: Introduce EM_ASM_3WCL KVM: x86: Introduce EM_ASM_1SRC2 KVM: x86: Introduce EM_ASM_2CL KVM: x86: Introduce EM_ASM_2W ...

Merge tag 'pm-6.18-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

2025-10-07T16:39:51+00:00

Pull more power management updates from Rafael Wysocki: "These are cpufreq fixes and cleanups on top of the material merged previously, a power management core code fix and updates of the runtime PM framework including unit tests, documentation updates and introduction of auto-cleanup macros for runtime PM "resume and get" and "get without resuming" operations. Specifics: - Make cpufreq drivers setting the default CPU transition latency to CPUFREQ_ETERNAL specify a proper default transition latency value instead which addresses a regression introduced during the 6.6 cycle that broke CPUFREQ_ETERNAL handling (Rafael Wysocki) - Make the cpufreq CPPC driver use a proper transition delay value when CPUFREQ_ETERNAL is returned by cppc_get_transition_latency() to indicate an error condition (Rafael Wysocki) - Make cppc_get_transition_latency() return a negative error code to indicate error conditions instead of using CPUFREQ_ETERNAL for this purpose and drop CPUFREQ_ETERNAL that has no other users (Rafael Wysocki, Gopi Krishna Menon) - Fix device leak in the mediatek cpufreq driver (Johan Hovold) - Set target frequency on all CPUs sharing a policy during frequency updates in the tegra186 cpufreq driver and make it initialize all cores to max frequencies (Aaron Kling) - Rust cpufreq helper cleanup (Thorsten Blum) - Make pm_runtime_put*() family of functions return 1 when the given device is already suspended which is consistent with the documentation (Brian Norris) - Add basic kunit tests for runtime PM API contracts and update return values in kerneldoc comments for the runtime PM API (Brian Norris, Dan Carpenter) - Add auto-cleanup macros for runtime PM "resume and get" and "get without resume" operations, use one of them in the PCI core and drop the existing "free" macro introduced for similar purpose, but somewhat cumbersome to use (Rafael Wysocki) - Make the core power management code avoid waiting on device links marked as SYNC_STATE_ONLY which is consistent with the handling of those device links elsewhere (Pin-yen Lin)" * tag 'pm-6.18-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: docs/zh_CN: Fix malformed table docs/zh_TW: Fix malformed table PM: runtime: Fix error checking for kunit_device_register() PM: runtime: Introduce one more usage counter guard cpufreq: Drop unused symbol CPUFREQ_ETERNAL ACPI: CPPC: Do not use CPUFREQ_ETERNAL as an error value cpufreq: CPPC: Avoid using CPUFREQ_ETERNAL as transition delay cpufreq: Make drivers using CPUFREQ_ETERNAL specify transition latency PM: runtime: Drop DEFINE_FREE() for pm_runtime_put() PCI/sysfs: Use runtime PM guard macro for auto-cleanup PM: runtime: Add auto-cleanup macros for "resume and get" operations cpufreq: tegra186: Initialize all cores to max frequencies cpufreq: tegra186: Set target frequency for all cpus in policy rust: cpufreq: streamline find_supply_names cpufreq: mediatek: fix device leak on probe failure PM: sleep: Do not wait on SYNC_STATE_ONLY device links PM: runtime: Update kerneldoc return codes PM: runtime: Make put{,_sync}() return 1 when already suspended PM: runtime: Add basic kunit tests for API contracts

Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2025-10-07T15:59:25+00:00

Pull arm64 fixes from Will Deacon: - Preserve old 'tt_core' UAPI for Hisilicon L3C PMU driver - Ensure linear alias of kprobes instruction page is not writable - Fix kernel stack unwinding from BPF - Fix build warnings from the Fujitsu uncore PMU documentation - Fix hang with deferred 'struct page' initialisation and MTE - Consolidate KPTI page-table re-writing code * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: arm64: mte: Do not flag the zero page as PG_mte_tagged docs: perf: Fujitsu: Fix htmldocs build warnings and errors arm64: mm: Move KPTI helpers to mmu.c tracing: Fix the bug where bpf_get_stackid returns -EFAULT on the ARM64 arm64: kprobes: call set_memory_rox() for kprobe page drivers/perf: hisi: Add tt_core_deprecated for compatibility

Merge branch 'pm-cpufreq'

2025-10-07T10:31:46+00:00

Merge cpufreq fixes and cleanups, mostly on top of those fixes, for 6.18-rc1: - Make cpufreq drivers setting the default CPU transition latency to CPUFREQ_ETERNAL specify a proper default transition latency value instead which addresses a regression introduced during the 6.6 cycle that broke CPUFREQ_ETERNAL handling (Rafael Wysocki) - Make the cpufreq CPPC driver use a proper transition delay value when CPUFREQ_ETERNAL is returned by cppc_get_transition_latency() to indicate an error condition (Rafael Wysocki) - Make cppc_get_transition_latency() return a negative error code to indicate error conditions instead of using CPUFREQ_ETERNAL for this purpose and drop CPUFREQ_ETERNAL that has no other users (Rafael Wysocki, Gopi Krishna Menon) - Fix device leak in the mediatek cpufreq driver (Johan Hovold) - Set target frequency on all CPUs sharing a policy during frequency updates in the tegra186 cpufreq driver and make it initialize all cores to max frequencies (Aaron Kling) - Rust cpufreq helper cleanup (Thorsten Blum) * pm-cpufreq: docs/zh_CN: Fix malformed table docs/zh_TW: Fix malformed table cpufreq: Drop unused symbol CPUFREQ_ETERNAL ACPI: CPPC: Do not use CPUFREQ_ETERNAL as an error value cpufreq: CPPC: Avoid using CPUFREQ_ETERNAL as transition delay cpufreq: Make drivers using CPUFREQ_ETERNAL specify transition latency cpufreq: tegra186: Initialize all cores to max frequencies cpufreq: tegra186: Set target frequency for all cpus in policy rust: cpufreq: streamline find_supply_names cpufreq: mediatek: fix device leak on probe failure