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2026-01-15sched/fair: Fix math notation errors in avg_vruntime commentZhan Xusheng
The avg_vruntime comment contains a couple of mathematical notation issues: - The summation over w_i * (V - v_i) is written in an ambiguous form - The delta term refers to v instead of v0, which is inconsistent with the code and preceding explanation Fix these to make the comment mathematically correct and consistent with the implementation. Signed-off-by: Zhan Xusheng <zhanxusheng@xiaomi.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20260114090035.19033-1-zhanxusheng@xiaomi.com
2026-01-15sched: Fix build for modules using set_tsk_need_resched()Gabriele Monaco
Commit adcc3bfa8806 ("sched: Adapt sched tracepoints for RV task model") added a tracepoint to the need_resched action that can be triggered also by set_tsk_need_resched. This function was previously accessible from out-of-tree modules but it's no longer available because the __trace_set_need_resched() symbol is not exported (together with the tracepoint itself, which was exported in a separate patch) and building such modules fails. Export __trace_set_need_resched to modules to fix those build issues. Fixes: adcc3bfa8806 ("sched: Adapt sched tracepoints for RV task model") Signed-off-by: Gabriele Monaco <gmonaco@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Phil Auld <pauld@redhat.com> Link: https://patch.msgid.link/20260112140413.362202-1-gmonaco@redhat.com
2026-01-15sched/deadline: Use ENQUEUE_MOVE to allow priority changePeter Zijlstra
Pierre reported hitting balance callback warnings for deadline tasks after commit 6455ad5346c9 ("sched: Move sched_class::prio_changed() into the change pattern"). It turns out that DEQUEUE_SAVE+ENQUEUE_RESTORE does not preserve DL priority and subsequently trips a balance pass -- where one was not expected. From discussion with Juri and Luca, the purpose of this clause was to deal with tasks new to DL and all those sites will have MOVE set (as well as CLASS, but MOVE is move conservative at this point). Per the previous patches MOVE is audited to always run the balance callbacks, so switch enqueue_dl_entity() to use MOVE for this case. Fixes: 6455ad5346c9 ("sched: Move sched_class::prio_changed() into the change pattern") Reported-by: Pierre Gondois <pierre.gondois@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Pierre Gondois <pierre.gondois@arm.com> Tested-by: Juri Lelli <juri.lelli@redhat.com> Link: https://patch.msgid.link/20260114130528.GB831285@noisy.programming.kicks-ass.net
2026-01-15sched: Deadline has dynamic priorityPeter Zijlstra
While FIFO/RR have static priority, DEADLINE is a dynamic priority scheme. Notably it has static priority -1. Do not assume the priority doesn't change for deadline tasks just because the static priority doesn't change. This ensures DL always sees {DE,EN}QUEUE_MOVE where appropriate. Fixes: ff77e4685359 ("sched/rt: Fix PI handling vs. sched_setscheduler()") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Pierre Gondois <pierre.gondois@arm.com> Tested-by: Juri Lelli <juri.lelli@redhat.com> Link: https://patch.msgid.link/20260114130528.GB831285@noisy.programming.kicks-ass.net
2026-01-15sched: Audit MOVE vs balance_callbacksPeter Zijlstra
The {DE,EN}QUEUE_MOVE flag indicates a task is allowed to change priority, which means there could be balance callbacks queued. Therefore audit all MOVE users and make sure they do run balance callbacks before dropping rq-lock. Fixes: 6455ad5346c9 ("sched: Move sched_class::prio_changed() into the change pattern") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Pierre Gondois <pierre.gondois@arm.com> Tested-by: Juri Lelli <juri.lelli@redhat.com> Link: https://patch.msgid.link/20260114130528.GB831285@noisy.programming.kicks-ass.net
2026-01-15sched: Fold rq-pin swizzle into __balance_callbacks()Peter Zijlstra
Prepare for more users needing the rq-pin swizzle. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Pierre Gondois <pierre.gondois@arm.com> Tested-by: Juri Lelli <juri.lelli@redhat.com> Link: https://patch.msgid.link/20260114130528.GB831285@noisy.programming.kicks-ass.net
2026-01-15sched/deadline: Avoid double update_rq_clock()Peter Zijlstra
When setup_new_dl_entity() is called from enqueue_task_dl() -> enqueue_dl_entity(), the rq-clock should already be updated, and calling update_rq_clock() again is not right. Move the update_rq_clock() to the one other caller of setup_new_dl_entity(): sched_init_dl_server(). Fixes: 9f239df55546 ("sched/deadline: Initialize dl_servers after SMP") Reported-by: Pierre Gondois <pierre.gondois@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Pierre Gondois <pierre.gondois@arm.com> Link: https://patch.msgid.link/20260113115622.GA831285@noisy.programming.kicks-ass.net
2026-01-15sched/deadline: Ensure get_prio_dl() is up-to-datePeter Zijlstra
Pratheek tripped a WARN and noted the following issue: > Inspecting the set of events that led to the warning being triggered > showed the following: > > systemd-1 [008] dN.31 ...: do_set_cpus_allowed: set_cpus_allowed begin! > > systemd-1 [008] dN.31 ...: sched_change_begin: Begin! > systemd-1 [008] dN.31 ...: sched_change_begin: Before dequeue_task()! > systemd-1 [008] dN.31 ...: update_curr_dl_se: update_curr_dl_se: ENQUEUE_REPLENISH > systemd-1 [008] dN.31 ...: enqueue_dl_entity: enqueue_dl_entity: ENQUEUE_REPLENISH > systemd-1 [008] dN.31 ...: replenish_dl_entity: Replenish before: 14815760217 > systemd-1 [008] dN.31 ...: replenish_dl_entity: Replenish after: 14816960047 > systemd-1 [008] dN.31 ...: sched_change_begin: Before put_prev_task()! > > systemd-1 [008] dN.31 ...: sched_change_end: Before enqueue_task()! > systemd-1 [008] dN.31 ...: sched_change_end: Before put_prev_task()! > systemd-1 [008] dN.31 ...: prio_changed_dl: Queuing pull task on prio change: 14815760217 -> 14816960047 > systemd-1 [008] dN.31 ...: prio_changed_dl: Queuing balance callback! > systemd-1 [008] dN.31 ...: sched_change_end: End! > > systemd-1 [008] dN.31 ...: do_set_cpus_allowed: set_cpus_allowed end! > systemd-1 [008] dN.21 ...: __schedule: Woops! Balance callback found! > > 1. sched_change_begin() from guard(sched_change) in > do_set_cpus_allowed() stashes the priority, which for the deadline > task, is "p->dl.deadline". > 2. The dequeue of the deadline task replenishes the deadline. > 3. The task is enqueued back after guard's scope ends and since there is > no *_CLASS flags set, sched_change_end() calls > dl_sched_class->prio_changed() which compares the deadline. > 4. Since deadline was moved on dequeue, prio_changed_dl() sees the value > differ from the stashed value and queues a balance pull callback. > 5. do_set_cpus_allowed() finishes and drops the rq_lock without doing a > do_balance_callbacks(). > 6. Grabbing the rq_lock() at subsequent __schedule() triggers the > warning since the balance pull callback was never executed before > dropping the lock. Meaning get_prio_dl() ought to update current and return an up-to-date value. Fixes: 6455ad5346c9 ("sched: Move sched_class::prio_changed() into the change pattern") Reported-by: K Prateek Nayak <kprateek.nayak@amd.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: K Prateek Nayak <kprateek.nayak@amd.com> Tested-by: K Prateek Nayak <kprateek.nayak@amd.com> Link: https://patch.msgid.link/20260106104113.GX3707891@noisy.programming.kicks-ass.net
2026-01-15Merge tag 'mm-hotfixes-stable-2026-01-15-08-03' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull misc fixes from Andrew Morton: - kerneldoc fixes from Bagas Sanjaya - DAMON fixes from SeongJae - mremap VMA-related fixes from Lorenzo - various singletons - please see the changelogs for details * tag 'mm-hotfixes-stable-2026-01-15-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (30 commits) drivers/dax: add some missing kerneldoc comment fields for struct dev_dax mm: numa,memblock: include <asm/numa.h> for 'numa_nodes_parsed' mailmap: add entry for Daniel Thompson tools/testing/selftests: fix gup_longterm for unknown fs mm/page_alloc: prevent pcp corruption with SMP=n iommu/sva: include mmu_notifier.h header mm: kmsan: fix poisoning of high-order non-compound pages tools/testing/selftests: add forked (un)/faulted VMA merge tests mm/vma: enforce VMA fork limit on unfaulted,faulted mremap merge too tools/testing/selftests: add tests for !tgt, src mremap() merges mm/vma: fix anon_vma UAF on mremap() faulted, unfaulted merge mm/zswap: fix error pointer free in zswap_cpu_comp_prepare() mm/damon/sysfs-scheme: cleanup access_pattern subdirs on scheme dir setup failure mm/damon/sysfs-scheme: cleanup quotas subdirs on scheme dir setup failure mm/damon/sysfs: cleanup attrs subdirs on context dir setup failure mm/damon/sysfs: cleanup intervals subdirs on attrs dir setup failure mm/damon/core: remove call_control in inactive contexts powerpc/watchdog: add support for hardlockup_sys_info sysctl mips: fix HIGHMEM initialization mm/hugetlb: ignore hugepage kernel args if hugepages are unsupported ...
2026-01-15ftrace: Do not over-allocate ftrace memoryGuenter Roeck
The pg_remaining calculation in ftrace_process_locs() assumes that ENTRIES_PER_PAGE multiplied by 2^order equals the actual capacity of the allocated page group. However, ENTRIES_PER_PAGE is PAGE_SIZE / ENTRY_SIZE (integer division). When PAGE_SIZE is not a multiple of ENTRY_SIZE (e.g. 4096 / 24 = 170 with remainder 16), high-order allocations (like 256 pages) have significantly more capacity than 256 * 170. This leads to pg_remaining being underestimated, which in turn makes skip (derived from skipped - pg_remaining) larger than expected, causing the WARN(skip != remaining) to trigger. Extra allocated pages for ftrace: 2 with 654 skipped WARNING: CPU: 0 PID: 0 at kernel/trace/ftrace.c:7295 ftrace_process_locs+0x5bf/0x5e0 A similar problem in ftrace_allocate_records() can result in allocating too many pages. This can trigger the second warning in ftrace_process_locs(). Extra allocated pages for ftrace WARNING: CPU: 0 PID: 0 at kernel/trace/ftrace.c:7276 ftrace_process_locs+0x548/0x580 Use the actual capacity of a page group to determine the number of pages to allocate. Have ftrace_allocate_pages() return the number of allocated pages to avoid having to calculate it. Use the actual page group capacity when validating the number of unused pages due to skipped entries. Drop the definition of ENTRIES_PER_PAGE since it is no longer used. Cc: stable@vger.kernel.org Fixes: 4a3efc6baff93 ("ftrace: Update the mcount_loc check of skipped entries") Link: https://patch.msgid.link/20260113152243.3557219-1-linux@roeck-us.net Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2026-01-15perf/core: Fix slow perf_event_task_exit() with LBR callstacksNamhyung Kim
I got a report that a task is stuck in perf_event_exit_task() waiting for global_ctx_data_rwsem. On large systems with lots threads, it'd have performance issues when it grabs the lock to iterate all threads in the system to allocate the context data. And it'd block task exit path which is problematic especially under memory pressure. perf_event_open perf_event_alloc attach_perf_ctx_data attach_global_ctx_data percpu_down_write (global_ctx_data_rwsem) for_each_process_thread alloc_task_ctx_data do_exit perf_event_exit_task percpu_down_read (global_ctx_data_rwsem) It should not hold the global_ctx_data_rwsem on the exit path. Let's skip allocation for exiting tasks and free the data carefully. Reported-by: Rosalie Fang <rosaliefang@google.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20260112165157.1919624-1-namhyung@kernel.org
2026-01-14powerpc/watchdog: add support for hardlockup_sys_info sysctlFeng Tang
Commit a9af76a78760 ("watchdog: add sys_info sysctls to dump sys info on system lockup") adds 'hardlock_sys_info' systcl knob for general kernel watchdog to control what kinds of system debug info to be dumped on hardlockup. Add similar support in powerpc watchdog code to make the sysctl knob more general, which also fixes a compiling warning in general watchdog code reported by 0day bot. Link: https://lkml.kernel.org/r/20251231080309.39642-1-feng.tang@linux.alibaba.com Fixes: a9af76a78760 ("watchdog: add sys_info sysctls to dump sys info on system lockup") Signed-off-by: Feng Tang <feng.tang@linux.alibaba.com> Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202512030920.NFKtekA7-lkp@intel.com/ Suggested-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14kho: validate preserved memory map during populationPasha Tatashin
If the previous kernel enabled KHO but did not call kho_finalize() (e.g., CONFIG_LIVEUPDATE=n or userspace skipped the finalization step), the 'preserved-memory-map' property in the FDT remains empty/zero. Previously, kho_populate() would succeed regardless of the memory map's state, reserving the incoming scratch regions in memblock. However, kho_memory_init() would later fail to deserialize the empty map. By that time, the scratch regions were already registered, leading to partial initialization and subsequent list corruption (freeing scratch area twice) during kho_init(). Move the validation of the preserved memory map earlier into kho_populate(). If the memory map is empty/NULL: 1. Abort kho_populate() immediately with -ENOENT. 2. Do not register or reserve the incoming scratch memory, allowing the new kernel to reclaim those pages as standard free memory. 3. Leave the global 'kho_in' state uninitialized. Consequently, kho_memory_init() sees no active KHO context (kho_in.mem_chunks_phys is 0) and falls back to kho_reserve_scratch(), allocating fresh scratch memory as if it were a standard cold boot. Link: https://lkml.kernel.org/r/20251223140140.2090337-1-pasha.tatashin@soleen.com Fixes: de51999e687c ("kho: allow memory preservation state updates after finalization") Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reported-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Closes: https://lore.kernel.org/all/20251218215613.GA17304@ranerica-svr.sc.intel.com Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Tested-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-14bpf: Properly mark live registers for indirect jumpsAnton Protopopov
For a `gotox rX` instruction the rX register should be marked as used in the compute_insn_live_regs() function. Fix this. Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com> Link: https://lore.kernel.org/r/20260114162544.83253-2-a.s.protopopov@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-01-14Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf after rc5Alexei Starovoitov
Cross-merge BPF and other fixes after downstream PR. No conflicts. Adjacent: Auto-merging MAINTAINERS Auto-merging Makefile Auto-merging kernel/bpf/verifier.c Auto-merging kernel/sched/ext.c Auto-merging mm/memcontrol.c Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-01-14dma/pool: Avoid allocating redundant poolsRobin Murphy
On smaller systems, e.g. embedded arm64, it is common for all memory to end up in ZONE_DMA32 or even ZONE_DMA. In such cases it is redundant to allocate a nominal pool for an empty higher zone that just ends up coming from a lower zone that should already have its own pool anyway. We already have logic to skip allocating a ZONE_DMA pool when that is empty, so generalise that to save memory in the case of other zones too. Signed-off-by: Robin Murphy <robin.murphy@arm.com> Tested-by: Vladimir Kondratiev <vladimir.kondratiev@mobileye.com> Reviewed-by: Baoquan He <bhe@redhat.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Link: https://lore.kernel.org/r/8ab8d8a620dee0109f33f5cb63d6bfeed35aac37.1768230104.git.robin.murphy@arm.com
2026-01-14dma/pool: Improve pool lookupRobin Murphy
If CONFIG_ZONE_DMA32 is enabled, but we have not allocated the corresponding atomic_pool_dma32, dma_guess_pool() may return the NULL value of that and fail a GFP_DMA32 allocation without trying to fall back to other pools which may exist. Furthermore, if no GFP_DMA pool exists, it is preferable to try GFP_DMA32 rather than immediately fall back to GFP_KERNEL with even less chance of success. Improve matters by encoding an explicit order of pool preference for each flag. Signed-off-by: Robin Murphy <robin.murphy@arm.com> Tested-by: Vladimir Kondratiev <vladimir.kondratiev@mobileye.com> Reviewed-by: Baoquan He <bhe@redhat.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Link: https://lore.kernel.org/r/c846b1a2f43295cac926c7af2ce907f62baec518.1768230104.git.robin.murphy@arm.com
2026-01-14vdso: Remove struct getcpu_cacheThomas Weißschuh
The cache parameter of getcpu() is useless nowadays for various reasons. * It is never passed by userspace for either the vDSO or syscalls. * It is never used by the kernel. * It could not be made to work on the current vDSO architecture. * The structure definition is not part of the UAPI headers. * vdso_getcpu() is superseded by restartable sequences in any case. Remove the struct and its header. As a side-effect this gets rid of an unwanted inclusion of the linux/ header namespace from vDSO code. [ tglx: Adapt to s390 upstream changes */ Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Heiko Carstens <hca@linux.ibm.com> # s390 Link: https://patch.msgid.link/20251230-getcpu_cache-v3-1-fb9c5f880ebe@linutronix.de
2026-01-13Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpfLinus Torvalds
Pull bpf fixes from Alexei Starovoitov: - Fix incorrect usage of BPF_TRAMP_F_ORIG_STACK in riscv JIT (Menglong Dong) - Fix reference count leak in bpf_prog_test_run_xdp() (Tetsuo Handa) - Fix metadata size check in bpf_test_run() (Toke Høiland-Jørgensen) - Check that BPF insn array is not allowed as a map for const strings (Deepanshu Kartikey) * tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: bpf: Fix reference count leak in bpf_prog_test_run_xdp() bpf: Reject BPF_MAP_TYPE_INSN_ARRAY in check_reg_const_str() selftests/bpf: Update xdp_context_test_run test to check maximum metadata size bpf, test_run: Subtract size of xdp_frame from allowed metadata size riscv, bpf: Fix incorrect usage of BPF_TRAMP_F_ORIG_STACK
2026-01-13bpf: Return EACCES for incorrect access to insn arrayAnton Protopopov
The insn_array_map_direct_value_addr() function currently returns -EINVAL when the offset within the map is invalid. Change this to return -EACCES, so that it is consistent with similar boundary access checks in the verifier. Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com> Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com> Link: https://lore.kernel.org/r/20260111153047.8388-3-a.s.protopopov@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-01-13bpf: Return proper address for non-zero offsets in insn arrayAnton Protopopov
The map_direct_value_addr() function of the instruction array map incorrectly adds offset to the resulting address. This is a bug, because later the resolve_pseudo_ldimm64() function adds the offset. Fix it. Corresponding selftests are added in a consequent commit. Fixes: 493d9e0d6083 ("bpf, x86: add support for indirect jumps") Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com> Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com> Link: https://lore.kernel.org/r/20260111153047.8388-2-a.s.protopopov@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-01-13bpf: return PTR_TO_BTF_ID | PTR_TRUSTED from BPF kfuncs by defaultMatt Bobrowski
Teach the BPF verifier to treat pointers to struct types returned from BPF kfuncs as implicitly trusted (PTR_TO_BTF_ID | PTR_TRUSTED) by default. Returning untrusted pointers to struct types from BPF kfuncs should be considered an exception only, and certainly not the norm. Update existing selftests to reflect the change in register type printing (e.g. `ptr_` becoming `trusted_ptr_` in verifier error messages). Link: https://lore.kernel.org/bpf/aV4nbCaMfIoM0awM@google.com/ Signed-off-by: Matt Bobrowski <mattbobrowski@google.com> Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20260113083949.2502978-1-mattbobrowski@google.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-01-13bpf: Optimize the performance of find_bpffs_btf_enumsDonglin Peng
Currently, vmlinux BTF is unconditionally sorted during the build phase. The function btf_find_by_name_kind executes the binary search branch, so find_bpffs_btf_enums can be optimized by using btf_find_by_name_kind. Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20260109130003.3313716-10-dolinux.peng@gmail.com
2026-01-13bpf: Skip anonymous types in type lookup for performanceDonglin Peng
Currently, vmlinux and kernel module BTFs are unconditionally sorted during the build phase, with named types placed at the end. Thus, anonymous types should be skipped when starting the search. In my vmlinux BTF, the number of anonymous types is 61,747, which means the loop count can be reduced by 61,747. Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20260109130003.3313716-9-dolinux.peng@gmail.com
2026-01-13btf: Verify BTF sortingDonglin Peng
This patch checks whether the BTF is sorted by name in ascending order. If sorted, binary search will be used when looking up types. Specifically, vmlinux and kernel module BTFs are always sorted during the build phase with anonymous types placed before named types, so we only need to identify the starting ID of named types. Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20260109130003.3313716-8-dolinux.peng@gmail.com
2026-01-13btf: Optimize type lookup with binary searchDonglin Peng
Improve btf_find_by_name_kind() performance by adding binary search support for sorted types. Falls back to linear search for compatibility. Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20260109130003.3313716-7-dolinux.peng@gmail.com
2026-01-13perf/core: Speed up kexec shutdown by avoiding unnecessary cross CPU callsJan H. Schönherr
There are typically a lot of PMUs registered, but in many cases only few of them have an event registered (like the "cpu" PMU in the presence of the watchdog). As the mutex is already held, it's safe to just check for existing events before doing the cross CPU call. This change saves tens of milliseconds from kexec time (perceived as steal time during a hypervisor host update), with <2ms remaining for this step in the shutdown. There might be additional potential for parallelization or we could just disable performance monitoring during the actual shutdown and be less graceful about it. Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2026-01-13genirq/cpuhotplug: Notify about affinity changes breaking the affinity maskImran Khan
During CPU offlining the interrupts affined to that CPU are moved to other online CPUs, which might break the original affinity mask if the outgoing CPU was the last online CPU in that mask. This change is not propagated to irq_desc::affinity_notify(), which leaves users of the affinity notifier mechanism with stale information. Avoid this by scheduling affinity change notification work for interrupts that were affined to the CPU being offlined, if the new target CPU is not part of the original affinity mask. Since irq_set_affinity_locked() uses the same logic to schedule affinity change notification work, split out this logic into a dedicated function and use that at both places. [ tglx: Removed the EXPORT(), removed the !SMP stub, moved the prototype, added a lockdep assert instead of a comment, fixed up coding style and name space. Polished and clarified the change log ] Signed-off-by: Imran Khan <imran.f.khan@oracle.com> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Link: https://patch.msgid.link/20260113143727.1041265-1-imran.f.khan@oracle.com
2026-01-13simplify the callers of file_open_name()Al Viro
It accepts ERR_PTR() for name and does the right thing in that case. That allows to simplify the logics in callers, making them trivial to switch to CLASS(filename). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2026-01-13struct filename ->refcnt doesn't need to be atomicAl Viro
... or visible outside of audit, really. Note that references held in delayed_filename always have refcount 1, and from the moment of complete_getname() or equivalent point in getname...() there won't be any references to struct filename instance left in places visible to other threads. Acked-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2026-01-13get rid of audit_reusename()Al Viro
Originally we tried to avoid multiple insertions into audit names array during retry loop by a cute hack - memorize the userland pointer and if there already is a match, just grab an extra reference to it. Cute as it had been, it had problems - two identical pointers had audit aux entries merged, two identical strings did not. Having different behaviour for syscalls that differ only by addresses of otherwise identical string arguments is obviously wrong - if nothing else, compiler can decide to merge identical string literals. Besides, this hack does nothing for non-audited processes - they get a fresh copy for retry. It's not time-critical, but having behaviour subtly differ that way is bogus. These days we have very few places that import filename more than once (9 functions total) and it's easy to massage them so we get rid of all re-imports. With that done, we don't need audit_reusename() anymore. There's no need to memorize userland pointer either. Acked-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2026-01-13bpf: Remove an unused parameter in check_func_protoSong Chen
The func_id parameter is not needed in check_func_proto. This patch removes it. Signed-off-by: Song Chen <chensong_2000@189.cn> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://patch.msgid.link/20260105155009.4581-1-chensong_2000@189.cn
2026-01-13bpf: Recognize special arithmetic shift in the verifierAlexei Starovoitov
cilium bpf_wiregard.bpf.c when compiled with -O1 fails to load with the following verifier log: 192: (79) r2 = *(u64 *)(r10 -304) ; R2=pkt(r=40) R10=fp0 fp-304=pkt(r=40) ... 227: (85) call bpf_skb_store_bytes#9 ; R0=scalar() 228: (bc) w2 = w0 ; R0=scalar() R2=scalar(smin=0,smax=umax=0xffffffff,var_off=(0x0; 0xffffffff)) 229: (c4) w2 s>>= 31 ; R2=scalar(smin=0,smax=umax=0xffffffff,smin32=-1,smax32=0,var_off=(0x0; 0xffffffff)) 230: (54) w2 &= -134 ; R2=scalar(smin=0,smax=umax=umax32=0xffffff7a,smax32=0x7fffff7a,var_off=(0x0; 0xffffff7a)) ... 232: (66) if w2 s> 0xffffffff goto pc+125 ; R2=scalar(smin=umin=umin32=0x80000000,smax=umax=umax32=0xffffff7a,smax32=-134,var_off=(0x80000000; 0x7fffff7a)) ... 238: (79) r4 = *(u64 *)(r10 -304) ; R4=scalar() R10=fp0 fp-304=scalar() 239: (56) if w2 != 0xffffff78 goto pc+210 ; R2=0xffffff78 // -136 ... 258: (71) r1 = *(u8 *)(r4 +0) R4 invalid mem access 'scalar' The error might confuse most bpf authors, since fp-304 slot had 'pkt' pointer at insn 192 and became 'scalar' at 238. That happened because bpf_skb_store_bytes() clears all packet pointers including those in the stack. On the first glance it might look like a bug in the source code, since ctx->data pointer should have been reloaded after the call to bpf_skb_store_bytes(). The relevant part of cilium source code looks like this: // bpf/lib/nodeport.h int dsr_set_ipip6() { if (ctx_adjust_hroom(...)) return DROP_INVALID; // -134 if (ctx_store_bytes(...)) return DROP_WRITE_ERROR; // -141 return 0; } bool dsr_fail_needs_reply(int code) { if (code == DROP_FRAG_NEEDED) // -136 return true; return false; } tail_nodeport_ipv6_dsr() { ret = dsr_set_ipip6(...); if (!IS_ERR(ret)) { ... } else { if (dsr_fail_needs_reply(ret)) return dsr_reply_icmp6(...); } } The code doesn't have arithmetic shift by 31 and it reloads ctx->data every time it needs to access it. So it's not a bug in the source code. The reason is DAGCombiner::foldSelectCCToShiftAnd() LLVM transformation: // If this is a select where the false operand is zero and the compare is a // check of the sign bit, see if we can perform the "gzip trick": // select_cc setlt X, 0, A, 0 -> and (sra X, size(X)-1), A // select_cc setgt X, 0, A, 0 -> and (not (sra X, size(X)-1)), A The conditional branch in dsr_set_ipip6() and its return values are optimized into BPF_ARSH plus BPF_AND: 227: (85) call bpf_skb_store_bytes#9 228: (bc) w2 = w0 229: (c4) w2 s>>= 31 ; R2=scalar(smin=0,smax=umax=0xffffffff,smin32=-1,smax32=0,var_off=(0x0; 0xffffffff)) 230: (54) w2 &= -134 ; R2=scalar(smin=0,smax=umax=umax32=0xffffff7a,smax32=0x7fffff7a,var_off=(0x0; 0xffffff7a)) after insn 230 the register w2 can only be 0 or -134, but the verifier approximates it, since there is no way to represent two scalars in bpf_reg_state. After fallthough at insn 232 the w2 can only be -134, hence the branch at insn 239: (56) if w2 != -136 goto pc+210 should be always taken, and trapping insn 258 should never execute. LLVM generated correct code, but the verifier follows impossible path and rejects valid program. To fix this issue recognize this special LLVM optimization and fork the verifier state. So after insn 229: (c4) w2 s>>= 31 the verifier has two states to explore: one with w2 = 0 and another with w2 = 0xffffffff which makes the verifier accept bpf_wiregard.c A similar pattern exists were OR operation is used in place of the AND operation, the verifier detects that pattern as well by forking the state before the OR operation with a scalar in range [-1,0]. Note there are 20+ such patterns in bpf_wiregard.o compiled with -O1 and -O2, but they're rarely seen in other production bpf programs, so push_stack() approach is not a concern. Reported-by: Hao Sun <sunhao.th@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Co-developed-by: Puranjay Mohan <puranjay@kernel.org> Signed-off-by: Puranjay Mohan <puranjay@kernel.org> Link: https://lore.kernel.org/r/20260112201424.816836-2-puranjay@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-01-13bpf: Consistently use reg_state() for register access in the verifierMykyta Yatsenko
Replace the pattern of declaring a local regs array from cur_regs() and then indexing into it with the more concise reg_state() helper. This simplifies the code by eliminating intermediate variables and makes register access more consistent throughout the verifier. Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20260113134826.2214860-1-mykyta.yatsenko5@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-01-13time/sched_clock: Use ACCESS_PRIVATE() to evaluate hrtimer::functionThomas Gleixner
This dereference of sched_clock_timer::function was missed when the hrtimer callback function pointer was marked private. Fixes: 04257da0c99c ("hrtimers: Make callback function pointer private") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Link: https://patch.msgid.link/875x95jw7q.ffs@tglx Closes: https://lore.kernel.org/oe-kbuild-all/202601131713.KsxhXQ0M-lkp@intel.com/
2026-01-13sched: Export hidden tracepoints to modulesGabriele Monaco
The tracepoints sched_entry, sched_exit and sched_set_need_resched are not exported to tracefs as trace events, this allows only kernel code to access them. Helper modules like [1] can be used to still have the tracepoints available to ftrace for debugging purposes, but they do rely on the tracepoints being exported. Export the 3 not exported tracepoints. Note that sched_set_state is already exported as the macro is called from modules. [1] - https://github.com/qais-yousef/sched_tp.git Fixes: adcc3bfa8806 ("sched: Adapt sched tracepoints for RV task model") Signed-off-by: Gabriele Monaco <gmonaco@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Phil Auld <pauld@redhat.com> Link: https://patch.msgid.link/20251205131621.135513-9-gmonaco@redhat.com
2026-01-13sched/deadline: Fix server stopping with runnable tasksGabriele Monaco
The deadline server can currently stop due to idle although fair tasks are runnable. This happens essentially when: * the server is set to idle, a task wakes up, the server stops * a task wakes up, the server sets itself to idle and stops right away Address both cases by clearing the server idle flag whenever a fair task wakes up and accounting also for pending tasks in the definition of idle. Fixes: f5a538c07df2 ("sched/deadline: Fix dl_server stop condition") Signed-off-by: Gabriele Monaco <gmonaco@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20260113085159.114226-3-gmonaco@redhat.com
2026-01-13sched: Provide idle_rq() helperPeter Zijlstra
A fix for the dl_server 'requires' idle_cpu() usage, which made me note that it and available_idle_cpu() are extern function calls. And while idle_cpu() is used outside of kernel/sched/, available_idle_cpu() is not. This makes it hard to make idle_cpu() an inline helper, so provide idle_rq() and implement idle_cpu() and available_idle_cpu() using that. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2026-01-13sched/deadline: Fix potential race in dl_add_task_root_domain()Pingfan Liu
The access rule for local_cpu_mask_dl requires it to be called on the local CPU with preemption disabled. However, dl_add_task_root_domain() currently violates this rule. Without preemption disabled, the following race can occur: 1. ThreadA calls dl_add_task_root_domain() on CPU 0 2. Gets pointer to CPU 0's local_cpu_mask_dl 3. ThreadA is preempted and migrated to CPU 1 4. ThreadA continues using CPU 0's local_cpu_mask_dl 5. Meanwhile, the scheduler on CPU 0 calls find_later_rq() which also uses local_cpu_mask_dl (with preemption properly disabled) 6. Both contexts now corrupt the same per-CPU buffer concurrently Fix this by moving the local_cpu_mask_dl access to the preemption disabled section. Closes: https://lore.kernel.org/lkml/aSBjm3mN_uIy64nz@jlelli-thinkpadt14gen4.remote.csb Fixes: 318e18ed22e8 ("sched/deadline: Walk up cpuset hierarchy to decide root domain when hot-unplug") Reported-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Pingfan Liu <piliu@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Juri Lelli <juri.lelli@redhat.com> Acked-by: Waiman Long <longman@redhat.com> Link: https://patch.msgid.link/20251125032630.8746-3-piliu@redhat.com
2026-01-13sched/deadline: Remove unnecessary comment in dl_add_task_root_domain()Pingfan Liu
The comments above dl_get_task_effective_cpus() and dl_add_task_root_domain() already explain how to fetch a valid root domain and protect against races. There's no need to repeat this inside dl_add_task_root_domain(). Remove the redundant comment to keep the code clean. No functional change. Signed-off-by: Pingfan Liu <piliu@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Juri Lelli <juri.lelli@redhat.com> Acked-by: Waiman Long <longman@redhat.com> Link: https://patch.msgid.link/20251125032630.8746-2-piliu@redhat.com
2026-01-13hrtimer: Drop _tv64() helpersThomas Weißschuh
Since ktime_t has become an alias to s64, these helpers are unnecessary. Migrate the few remaining users to the regular helpers and remove the now dead code. Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Link: https://patch.msgid.link/20260107-hrtimer-header-cleanup-v1-3-1a698ef0ddae@linutronix.de
2026-01-13hrtimer: Remove public definition of HIGH_RES_NSECThomas Weißschuh
This constant is only used in a single place and is has a very generic name polluting the global namespace. Move the constant closer to its only user. Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Link: https://patch.msgid.link/20260107-hrtimer-header-cleanup-v1-2-1a698ef0ddae@linutronix.de
2026-01-13hrtimer: Fix softirq base check in update_needs_ipi()Thomas Weißschuh
The 'clockid' field is not the correct way to check for a softirq base. Fix the check to correctly compare the base type instead of the clockid. Fixes: 1e7f7fbcd40c ("hrtimer: Avoid more SMP function calls in clock_was_set()") Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260107-hrtimer-clock-base-check-v1-1-afb5dbce94a1@linutronix.de
2026-01-13genirq: Move clear of kstat_irqs to free_desc()Luigi Rizzo
desc_set_defaults() has a loop to clear the per-cpu counters kstats_irq. This is only needed in free_desc(), which is used with non-sparse IRQs so that the interrupt descriptor can be recycled. For newly allocated descriptors, the memory comes from alloc_percpu() and is already zeroed out. Move the loop to free_desc() to avoid wasting time unnecessarily. Signed-off-by: Luigi Rizzo <lrizzo@google.com> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Link: https://patch.msgid.link/20260112083234.2665832-1-lrizzo@google.com
2026-01-13genirq: Update effective affinity for redirected interruptsRadu Rendec
For redirected interrupts, irq_chip_redirect_set_affinity() does not update the effective affinity mask, which then triggers the warning in irq_validate_effective_affinity(). Also, because the effective affinity mask is empty, the cpumask_test_cpu(smp_processor_id(), m) condition in demux_redirect_remote() is always false, and the interrupt is always redirected, even if it's already running on the target CPU. Set the effective affinity mask to be the same as the requested affinity mask. It's worth noting that irq_do_set_affinity() filters out offline CPUs before calling chip->irq_set_affinity() (unless `force` is set), so the mask passed to irq_chip_redirect_set_affinity() is already filtered. The solution is not ideal because it may lie about the effective affinity of the demultiplexed ("child") interrupt. If the requested affinity mask includes multiple CPUs, the effective affinity, in reality, is the intersection between the requested mask and the demultiplexing ("parent") interrupt's effective affinity mask, plus the first CPU in the requested mask. Accurately describing the effective affinity of the demultiplexed interrupt is not trivial because it requires keeping track of the demultiplexing interrupt's effective affinity. That is tricky in the context of CPU hot(un)plugging, where interrupt migration ordering is not guaranteed. The solution in the initial version of the fixed patch, which stored the first CPU of the demultiplexing interrupt's effective affinity in the `target_cpu` field, has its own drawbacks and limitations. Fixes: fcc1d0dabdb6 ("genirq: Add interrupt redirection infrastructure") Reported-by: Jon Hunter <jonathanh@nvidia.com> Signed-off-by: Radu Rendec <rrendec@redhat.com> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Tested-by: Jon Hunter <jonathanh@nvidia.com> Link: https://patch.msgid.link/20260112211402.2927336-1-rrendec@redhat.com Closes: https://lore.kernel.org/all/44509520-f29b-4b8a-8986-5eae3e022eb7@nvidia.com/
2026-01-13genirq: Warn about using IRQF_ONESHOT without a threaded handlerSebastian Andrzej Siewior
IRQF_ONESHOT disables the interrupt source until after the threaded handler completed its work. This is needed to allow the threaded handler to run - otherwise the CPU will get back to the interrupt handler because the interrupt source remains active and the threaded handler will not able to do its work. Specifying IRQF_ONESHOT without a threaded handler does not make sense. It could be a leftover if the handler _was_ threaded and changed back to primary and the flag was not removed. This can be problematic in the `threadirqs' case because the handler is exempt from forced-threading. This in turn can become a problem on a PREEMPT_RT system if the handler attempts to acquire sleeping locks. Warn about missing threaded handlers with the IRQF_ONESHOT flag. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Link: https://patch.msgid.link/20260112134013.eQWyReHR@linutronix.de
2026-01-12bpf, btf: Enforce destructor kfunc type with CFISami Tolvanen
Ensure that registered destructor kfuncs have the same type as btf_dtor_kfunc_t to avoid a kernel panic on systems with CONFIG_CFI enabled. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Acked-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/r/20260110082548.113748-10-samitolvanen@google.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-01-12bpf: crypto: Use the correct destructor kfunc typeSami Tolvanen
With CONFIG_CFI enabled, the kernel strictly enforces that indirect function calls use a function pointer type that matches the target function. I ran into the following type mismatch when running BPF self-tests: CFI failure at bpf_obj_free_fields+0x190/0x238 (target: bpf_crypto_ctx_release+0x0/0x94; expected type: 0xa488ebfc) Internal error: Oops - CFI: 00000000f2008228 [#1] SMP ... As bpf_crypto_ctx_release() is also used in BPF programs and using a void pointer as the argument would make the verifier unhappy, add a simple stub function with the correct type and register it as the destructor kfunc instead. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Acked-by: Yonghong Song <yonghong.song@linux.dev> Tested-by: Viktor Malik <vmalik@redhat.com> Link: https://lore.kernel.org/r/20260110082548.113748-7-samitolvanen@google.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-01-12Merge tag 'cgroup-for-6.19-rc5-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup fix from Tejun Heo: - Fix -Wflex-array-member-not-at-end warnings in cgroup_root * tag 'cgroup-for-6.19-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: Eliminate cgrp_ancestor_storage in cgroup_root
2026-01-12cpuset: replace direct lockdep_assert_held() with ↵Zhao Mengmeng
lockdep_assert_cpuset_lock_held() We already added lockdep_assert_cpuset_lock_held(), use this new function to keep consistency. Signed-off-by: Zhao Mengmeng <zhaomengmeng@kylinos.cn> Signed-off-by: Tejun Heo <tj@kernel.org>