user/sven/linux.git/kernel/time, branch v6.6.10

hrtimers: Push pending hrtimers away from outgoing CPU earlier

2023-12-13T17:44:56Z

[ Upstream commit 5c0930ccaad5a74d74e8b18b648c5eb21ed2fe94 ] 2b8272ff4a70 ("cpu/hotplug: Prevent self deadlock on CPU hot-unplug") solved the straight forward CPU hotplug deadlock vs. the scheduler bandwidth timer. Yu discovered a more involved variant where a task which has a bandwidth timer started on the outgoing CPU holds a lock and then gets throttled. If the lock required by one of the CPU hotplug callbacks the hotplug operation deadlocks because the unthrottling timer event is not handled on the dying CPU and can only be recovered once the control CPU reaches the hotplug state which pulls the pending hrtimers from the dead CPU. Solve this by pushing the hrtimers away from the dying CPU in the dying callbacks. Nothing can queue a hrtimer on the dying CPU at that point because all other CPUs spin in stop_machine() with interrupts disabled and once the operation is finished the CPU is marked offline. Reported-by: Yu Liao Signed-off-by: Thomas Gleixner Tested-by: Liu Tie Link: https://lore.kernel.org/r/87a5rphara.ffs@tglx Signed-off-by: Sasha Levin

Merge tag 'timers-urgent-2023-09-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2023-09-02T16:01:48Z

Pull timer fix from Ingo Molnar: "Fix false positive 'softirq work is pending' messages on -rt kernels, caused by a buggy factoring-out of existing code" * tag 'timers-urgent-2023-09-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tick/rcu: Fix false positive "softirq work is pending" messages

Merge tag 'docs-6.6' of git://git.lwn.net/linux

2023-08-31T03:05:42Z

Pull documentation updates from Jonathan Corbet: "Documentation work keeps chugging along; this includes: - Work from Carlos Bilbao to integrate rustdoc output into the generated HTML documentation. This took some work to figure out how to do it without slowing the docs build and without creating people who don't have Rust installed, but Carlos got there - Move the loongarch and mips architecture documentation under Documentation/arch/ - Some more maintainer documentation from Jakub ... plus the usual assortment of updates, translations, and fixes" * tag 'docs-6.6' of git://git.lwn.net/linux: (56 commits) Docu: genericirq.rst: fix irq-example input: docs: pxrc: remove reference to phoenix-sim Documentation: serial-console: Fix literal block marker docs/mm: remove references to hmm_mirror ops and clean typos docs/zh_CN: correct regi_chg(),regi_add() to region_chg(),region_add() Documentation: Fix typos Documentation/ABI: Fix typos scripts: kernel-doc: fix macro handling in enums scripts: kernel-doc: parse DEFINE_DMA_UNMAP_[ADDR|LEN] Documentation: riscv: Update boot image header since EFI stub is supported Documentation: riscv: Add early boot document Documentation: arm: Add bootargs to the table of added DT parameters docs: kernel-parameters: Refer to the correct bitmap function doc: update params of memhp_default_state= docs: Add book to process/kernel-docs.rst docs: sparse: fix invalid link addresses docs: vfs: clean up after the iterate() removal docs: Add a section on surveys to the researcher guidelines docs: move mips under arch docs: move loongarch under arch ...

tick/rcu: Fix false positive "softirq work is pending" messages

2023-08-30T10:20:28Z

In commit 0345691b24c0 ("tick/rcu: Stop allowing RCU_SOFTIRQ in idle") the new function report_idle_softirq() was created by breaking code out of the existing can_stop_idle_tick() for kernels v5.18 and newer. In doing so, the code essentially went from a one conditional: if (a && b && c) warn(); to a three conditional: if (!a) return; if (!b) return; if (!c) return; warn(); But that conversion got the condition for the RT specific local_bh_blocked() wrong. The original condition was: !local_bh_blocked() but the conversion failed to negate it so it ended up as: if (!local_bh_blocked()) return false; This issue lay dormant until another fixup for the same commit was added in commit a7e282c77785 ("tick/rcu: Fix bogus ratelimit condition"). This commit realized the ratelimit was essentially set to zero instead of ten, and hence *no* softirq pending messages would ever be issued. Once this commit was backported via linux-stable, both the v6.1 and v6.4 preempt-rt kernels started printing out 10 instances of this at boot: NOHZ tick-stop error: local softirq work is pending, handler #80!!! Remove the negation and return when local_bh_blocked() evaluates to true to bring the correct behaviour back. Fixes: 0345691b24c0 ("tick/rcu: Stop allowing RCU_SOFTIRQ in idle") Signed-off-by: Paul Gortmaker Signed-off-by: Thomas Gleixner Tested-by: Ahmad Fatoum Reviewed-by: Wen Yang Acked-by: Frederic Weisbecker Link: https://lore.kernel.org/r/20230818200757.1808398-1-paul.gortmaker@windriver.com

Merge tag 'linux-kselftest-kunit-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

2023-08-29T01:56:38Z

Pull kunit updates from Shuah Khan: - add support for running Rust documentation tests as KUnit tests - make init, str, sync, types doctests compilable/testable - add support for attributes API which include speed, modules attributes, ability to filter and report attributes - add support for marking tests slow using attributes API - add attributes API documentation - fix a wild-memory-access bug in kunit_filter_suites() and a possible memory leak in kunit_filter_suites() - add support for counting number of test suites in a module, list action to kunit test modules, and test filtering on module tests * tag 'linux-kselftest-kunit-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (25 commits) kunit: fix struct kunit_attr header kunit: replace KUNIT_TRIGGER_STATIC_STUB maro with KUNIT_STATIC_STUB_REDIRECT kunit: Allow kunit test modules to use test filtering kunit: Make 'list' action available to kunit test modules kunit: Report the count of test suites in a module kunit: fix uninitialized variables bug in attributes filtering kunit: fix possible memory leak in kunit_filter_suites() kunit: fix wild-memory-access bug in kunit_filter_suites() kunit: Add documentation of KUnit test attributes kunit: add tests for filtering attributes kunit: time: Mark test as slow using test attributes kunit: memcpy: Mark tests as slow using test attributes kunit: tool: Add command line interface to filter and report attributes kunit: Add ability to filter attributes kunit: Add module attribute kunit: Add speed attribute kunit: Add test attributes API structure MAINTAINERS: add Rust KUnit files to the KUnit entry rust: support running Rust documentation tests as KUnit ones rust: types: make doctests compilable/testable ...

kunit: time: Mark test as slow using test attributes

2023-07-26T19:29:35Z

Mark the time KUnit test, time64_to_tm_test_date_range, as slow using test attributes. This test ran relatively much slower than most other KUnit tests. By marking this test as slow, the test can now be filtered using the KUnit test attribute filtering feature. Example: --filter "speed>slow". This will run only the tests that have speeds faster than slow. The slow attribute will also be outputted in KTAP. Reviewed-by: David Gow Signed-off-by: Rae Moar Signed-off-by: Shuah Khan

clocksource: Handle negative skews in "skew is too large" messages

2023-07-14T22:17:09Z

The nanosecond-to-millisecond skew computation uses unsigned arithmetic, which produces user-unfriendly large positive numbers for negative skews. Therefore, use signed arithmetic for this computation in order to preserve the negativity. Reported-by: Chris Bainbridge Reported-by: Feng Tang Fixes: dd029269947a ("clocksource: Improve "skew is too large" messages") Reviewed-by: Feng Tang Tested-by: Chris Bainbridge Signed-off-by: Paul E. McKenney

time: add kernel-doc in time.c

2023-07-14T19:47:07Z

Add kernel-doc for all APIs that do not already have it. Signed-off-by: Randy Dunlap Cc: John Stultz Cc: Thomas Gleixner Cc: Stephen Boyd Cc: Jonathan Corbet Cc: linux-doc@vger.kernel.org Acked-by: John Stultz Signed-off-by: Jonathan Corbet Link: https://lore.kernel.org/r/20230704052405.5089-3-rdunlap@infradead.org

Merge tag 'hardening-v6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2023-06-28T04:24:18Z

Pull hardening updates from Kees Cook: "There are three areas of note: A bunch of strlcpy()->strscpy() conversions ended up living in my tree since they were either Acked by maintainers for me to carry, or got ignored for multiple weeks (and were trivial changes). The compiler option '-fstrict-flex-arrays=3' has been enabled globally, and has been in -next for the entire devel cycle. This changes compiler diagnostics (though mainly just -Warray-bounds which is disabled) and potential UBSAN_BOUNDS and FORTIFY _warning_ coverage. In other words, there are no new restrictions, just potentially new warnings. Any new FORTIFY warnings we've seen have been fixed (usually in their respective subsystem trees). For more details, see commit df8fc4e934c12b. The under-development compiler attribute __counted_by has been added so that we can start annotating flexible array members with their associated structure member that tracks the count of flexible array elements at run-time. It is possible (likely?) that the exact syntax of the attribute will change before it is finalized, but GCC and Clang are working together to sort it out. Any changes can be made to the macro while we continue to add annotations. As an example of that last case, I have a treewide commit waiting with such annotations found via Coccinelle: https://git.kernel.org/linus/adc5b3cb48a049563dc673f348eab7b6beba8a9b Also see commit dd06e72e68bcb4 for more details. Summary: - Fix KMSAN vs FORTIFY in strlcpy/strlcat (Alexander Potapenko) - Convert strreplace() to return string start (Andy Shevchenko) - Flexible array conversions (Arnd Bergmann, Wyes Karny, Kees Cook) - Add missing function prototypes seen with W=1 (Arnd Bergmann) - Fix strscpy() kerndoc typo (Arne Welzel) - Replace strlcpy() with strscpy() across many subsystems which were either Acked by respective maintainers or were trivial changes that went ignored for multiple weeks (Azeem Shaikh) - Remove unneeded cc-option test for UBSAN_TRAP (Nick Desaulniers) - Add KUnit tests for strcat()-family - Enable KUnit tests of FORTIFY wrappers under UML - Add more complete FORTIFY protections for strlcat() - Add missed disabling of FORTIFY for all arch purgatories. - Enable -fstrict-flex-arrays=3 globally - Tightening UBSAN_BOUNDS when using GCC - Improve checkpatch to check for strcpy, strncpy, and fake flex arrays - Improve use of const variables in FORTIFY - Add requested struct_size_t() helper for types not pointers - Add __counted_by macro for annotating flexible array size members" * tag 'hardening-v6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (54 commits) netfilter: ipset: Replace strlcpy with strscpy uml: Replace strlcpy with strscpy um: Use HOST_DIR for mrproper kallsyms: Replace all non-returning strlcpy with strscpy sh: Replace all non-returning strlcpy with strscpy of/flattree: Replace all non-returning strlcpy with strscpy sparc64: Replace all non-returning strlcpy with strscpy Hexagon: Replace all non-returning strlcpy with strscpy kobject: Use return value of strreplace() lib/string_helpers: Change returned value of the strreplace() jbd2: Avoid printing outside the boundary of the buffer checkpatch: Check for 0-length and 1-element arrays riscv/purgatory: Do not use fortified string functions s390/purgatory: Do not use fortified string functions x86/purgatory: Do not use fortified string functions acpi: Replace struct acpi_table_slit 1-element array with flex-array clocksource: Replace all non-returning strlcpy with strscpy string: use __builtin_memcpy() in strlcpy/strlcat staging: most: Replace all non-returning strlcpy with strscpy drm/i2c: tda998x: Replace all non-returning strlcpy with strscpy ...

Merge tag 'sched-core-2023-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2023-06-27T21:03:21Z

Pull scheduler updates from Ingo Molnar: "Scheduler SMP load-balancer improvements: - Avoid unnecessary migrations within SMT domains on hybrid systems. Problem: On hybrid CPU systems, (processors with a mixture of higher-frequency SMT cores and lower-frequency non-SMT cores), under the old code lower-priority CPUs pulled tasks from the higher-priority cores if more than one SMT sibling was busy - resulting in many unnecessary task migrations. Solution: The new code improves the load balancer to recognize SMT cores with more than one busy sibling and allows lower-priority CPUs to pull tasks, which avoids superfluous migrations and lets lower-priority cores inspect all SMT siblings for the busiest queue. - Implement the 'runnable boosting' feature in the EAS balancer: consider CPU contention in frequency, EAS max util & load-balance busiest CPU selection. This improves CPU utilization for certain workloads, while leaves other key workloads unchanged. Scheduler infrastructure improvements: - Rewrite the scheduler topology setup code by consolidating it into the build_sched_topology() helper function and building it dynamically on the fly. - Resolve the local_clock() vs. noinstr complications by rewriting the code: provide separate sched_clock_noinstr() and local_clock_noinstr() functions to be used in instrumentation code, and make sure it is all instrumentation-safe. Fixes: - Fix a kthread_park() race with wait_woken() - Fix misc wait_task_inactive() bugs unearthed by the -rt merge: - Fix UP PREEMPT bug by unifying the SMP and UP implementations - Fix task_struct::saved_state handling - Fix various rq clock update bugs, unearthed by turning on the rq clock debugging code. - Fix the PSI WINDOW_MIN_US trigger limit, which was easy to trigger by creating enough cgroups, by removing the warnign and restricting window size triggers to PSI file write-permission or CAP_SYS_RESOURCE. - Propagate SMT flags in the topology when removing degenerate domain - Fix grub_reclaim() calculation bug in the deadline scheduler code - Avoid resetting the min update period when it is unnecessary, in psi_trigger_destroy(). - Don't balance a task to its current running CPU in load_balance(), which was possible on certain NUMA topologies with overlapping groups. - Fix the sched-debug printing of rq->nr_uninterruptible Cleanups: - Address various -Wmissing-prototype warnings, as a preparation to (maybe) enable this warning in the future. - Remove unused code - Mark more functions __init - Fix shadow-variable warnings" * tag 'sched-core-2023-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (50 commits) sched/core: Avoid multiple calling update_rq_clock() in __cfsb_csd_unthrottle() sched/core: Avoid double calling update_rq_clock() in __balance_push_cpu_stop() sched/core: Fixed missing rq clock update before calling set_rq_offline() sched/deadline: Update GRUB description in the documentation sched/deadline: Fix bandwidth reclaim equation in GRUB sched/wait: Fix a kthread_park race with wait_woken() sched/topology: Mark set_sched_topology() __init sched/fair: Rename variable cpu_util eff_util arm64/arch_timer: Fix MMIO byteswap sched/fair, cpufreq: Introduce 'runnable boosting' sched/fair: Refactor CPU utilization functions cpuidle: Use local_clock_noinstr() sched/clock: Provide local_clock_noinstr() x86/tsc: Provide sched_clock_noinstr() clocksource: hyper-v: Provide noinstr sched_clock() clocksource: hyper-v: Adjust hv_read_tsc_page_tsc() to avoid special casing U64_MAX x86/vdso: Fix gettimeofday masking math64: Always inline u128 version of mul_u64_u64_shr() s390/time: Provide sched_clock_noinstr() loongarch: Provide noinstr sched_clock_read() ...