lwn.git/kernel/trace, branch master

Merge tag 'trace-latency-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2026-04-17T17:12:11+00:00

Pull tracing latency update from Steven Rostedt: - Add TIMERLAT_ALIGN osnoise option Add a timer alignment option for timerlat that makes it work like the cyclictest -A option. timelat creates threads to test the latency of the kernel. The alignment option will have these threads trigger at the alignment offsets from each other. Instead of having each thread wake up at the exact same time, if the alignment is set to "20" each thread will wake up at 20 microseconds from the previous one. * tag 'trace-latency-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing/osnoise: Add option to align tlat threads

Merge tag 'trace-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2026-04-17T16:43:12+00:00

Pull tracing updates from Steven Rostedt: - Fix printf format warning for bprintf sunrpc uses a trace_printk() that triggers a printf warning during the compile. Move the __printf() attribute around for when debugging is not enabled the warning will go away - Remove redundant check for EVENT_FILE_FL_FREED in event_filter_write() The FREED flag is checked in the call to event_file_file() and then checked again right afterward, which is unneeded - Clean up event_file_file() and event_file_data() helpers These helper functions played a different role in the past, but now with eventfs, the READ_ONCE() isn't needed. Simplify the code a bit and also add a warning to event_file_data() if the file or its data is not present - Remove updating file->private_data in tracing open All access to the file private data is handled by the helper functions, which do not use file->private_data. Stop updating it on open - Show ENUM names in function arguments via BTF in function tracing When showing the function arguments when func-args option is set for function tracing, if one of the arguments is found to be an enum, show the name of the enum instead of its number - Add new trace_call__##name() API for tracepoints Tracepoints are enabled via static_branch() blocks, where when not enabled, there's only a nop that is in the code where the execution will just skip over it. When tracing is enabled, the nop is converted to a direct jump to the tracepoint code. Sometimes more calculations are required to be performed to update the parameters of the tracepoint. In this case, trace_##name##_enabled() is called which is a static_branch() that gets enabled only when the tracepoint is enabled. This allows the extra calculations to also be skipped by the nop: if (trace_foo_enabled()) { x = bar(); trace_foo(x); } Where the x=bar() is only performed when foo is enabled. The problem with this approach is that there's now two static_branch() calls. One for checking if the tracepoint is enabled, and then again to know if the tracepoint should be called. The second one is redundant Introduce trace_call__foo() that will call the foo() tracepoint directly without doing a static_branch(): if (trace_foo_enabled()) { x = bar(); trace_call__foo(); } - Update various locations to use the new trace_call__##name() API - Move snapshot code out of trace.c Cleaning up trace.c to not be a "dump all", move the snapshot code out of it and into a new trace_snapshot.c file - Clean up some "%*.s" to "%*s" - Allow boot kernel command line options to be called multiple times Have options like: ftrace_filter=foo ftrace_filter=bar ftrace_filter=zoo Equal to: ftrace_filter=foo,bar,zoo - Fix ipi_raise event CPU field to be a CPU field The ipi_raise target_cpus field is defined as a __bitmask(). There is now a __cpumask() field definition. Update the field to use that - Have hist_field_name() use a snprintf() and not a series of strcat() It's safer to use snprintf() that a series of strcat() - Fix tracepoint regfunc balancing A tracepoint can define a "reg" and "unreg" function that gets called before the tracepoint is enabled, and after it is disabled respectively. But on error, after the "reg" func is called and the tracepoint is not enabled, the "unreg" function is not called to tear down what the "reg" function performed - Fix output that shows what histograms are enabled Event variables are displayed incorrectly in the histogram output Instead of "sched.sched_wakeup.$var", it is showing "$sched.sched_wakeup.var" where the '$' is in the incorrect location - Some other simple cleanups * tag 'trace-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (24 commits) selftests/ftrace: Add test case for fully-qualified variable references tracing: Fix fully-qualified variable reference printing in histograms tracepoint: balance regfunc() on func_add() failure in tracepoint_add_func() tracing: Rebuild full_name on each hist_field_name() call tracing: Report ipi_raise target CPUs as cpumask tracing: Remove duplicate latency_fsnotify() stub tracing: Preserve repeated trace_trigger boot parameters tracing: Append repeated boot-time tracing parameters tracing: Remove spurious default precision from show_event_trigger/filter formats cpufreq: Use trace_call__##name() at guarded tracepoint call sites tracing: Remove tracing_alloc_snapshot() when snapshot isn't defined tracing: Move snapshot code out of trace.c and into trace_snapshot.c mm: damon: Use trace_call__##name() at guarded tracepoint call sites btrfs: Use trace_call__##name() at guarded tracepoint call sites spi: Use trace_call__##name() at guarded tracepoint call sites i2c: Use trace_call__##name() at guarded tracepoint call sites kernel: Use trace_call__##name() at guarded tracepoint call sites tracepoint: Add trace_call__##name() API tracing: trace_mmap.h: fix a kernel-doc warning tracing: Pretty-print enum parameters in function arguments ...

Merge tag 'probes-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2026-04-17T16:18:32+00:00

Pull fprobe update from Masami Hiramatsu: - do not zero out unused fgraph_data. This removes unneeded memset of fgraph_data in fprobe entry handler. * tag 'probes-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing: fprobe: do not zero out unused fgraph_data

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2026-04-17T14:18:03+00:00

Pull kvm updates from Paolo Bonzini: "Arm: - Add support for tracing in the standalone EL2 hypervisor code, which should help both debugging and performance analysis. This uses the new infrastructure for 'remote' trace buffers that can be exposed by non-kernel entities such as firmware, and which came through the tracing tree - Add support for GICv5 Per Processor Interrupts (PPIs), as the starting point for supporting the new GIC architecture in KVM - Finally add support for pKVM protected guests, where pages are unmapped from the host as they are faulted into the guest and can be shared back from the guest using pKVM hypercalls. Protected guests are created using a new machine type identifier. As the elusive guestmem has not yet delivered on its promises, anonymous memory is also supported This is only a first step towards full isolation from the host; for example, the CPU register state and DMA accesses are not yet isolated. Because this does not really yet bring fully what it promises, it is hidden behind CONFIG_ARM_PKVM_GUEST + 'kvm-arm.mode=protected', and also triggers TAINT_USER when a VM is created. Caveat emptor - Rework the dreaded user_mem_abort() function to make it more maintainable, reducing the amount of state being exposed to the various helpers and rendering a substantial amount of state immutable - Expand the Stage-2 page table dumper to support NV shadow page tables on a per-VM basis - Tidy up the pKVM PSCI proxy code to be slightly less hard to follow - Fix both SPE and TRBE in non-VHE configurations so that they do not generate spurious, out of context table walks that ultimately lead to very bad HW lockups - A small set of patches fixing the Stage-2 MMU freeing in error cases - Tighten-up accepted SMC immediate value to be only #0 for host SMCCC calls - The usual cleanups and other selftest churn LoongArch: - Use CSR_CRMD_PLV for kvm_arch_vcpu_in_kernel() - Add DMSINTC irqchip in kernel support RISC-V: - Fix steal time shared memory alignment checks - Fix vector context allocation leak - Fix array out-of-bounds in pmu_ctr_read() and pmu_fw_ctr_read_hi() - Fix double-free of sdata in kvm_pmu_clear_snapshot_area() - Fix integer overflow in kvm_pmu_validate_counter_mask() - Fix shift-out-of-bounds in make_xfence_request() - Fix lost write protection on huge pages during dirty logging - Split huge pages during fault handling for dirty logging - Skip CSR restore if VCPU is reloaded on the same core - Implement kvm_arch_has_default_irqchip() for KVM selftests - Factored-out ISA checks into separate sources - Added hideleg to struct kvm_vcpu_config - Factored-out VCPU config into separate sources - Support configuration of per-VM HGATP mode from KVM user space s390: - Support for ESA (31-bit) guests inside nested hypervisors - Remove restriction on memslot alignment, which is not needed anymore with the new gmap code - Fix LPSW/E to update the bear (which of course is the breaking event address register) x86: - Shut up various UBSAN warnings on reading module parameter before they were initialized - Don't zero-allocate page tables that are used for splitting hugepages in the TDP MMU, as KVM is guaranteed to set all SPTEs in the page table and thus write all bytes - As an optimization, bail early when trying to unsync 4KiB mappings if the target gfn can just be mapped with a 2MiB hugepage x86 generic: - Copy single-chunk MMIO write values into struct kvm_vcpu (more precisely struct kvm_mmio_fragment) to fix use-after-free stack bugs where KVM would dereference stack pointer after an exit to userspace - Clean up and comment the emulated MMIO code to try to make it easier to maintain (not necessarily "easy", but "easier") - Move VMXON+VMXOFF and EFER.SVME toggling out of KVM (not *all* of VMX and SVM enabling) as it is needed for trusted I/O - Advertise support for AVX512 Bit Matrix Multiply (BMM) instructions - Immediately fail the build if a required #define is missing in one of KVM's headers that is included multiple times - Reject SET_GUEST_DEBUG with -EBUSY if there's an already injected exception, mostly to prevent syzkaller from abusing the uAPI to trigger WARNs, but also because it can help prevent userspace from unintentionally crashing the VM - Exempt SMM from CPUID faulting on Intel, as per the spec - Misc hardening and cleanup changes x86 (AMD): - Fix and optimize IRQ window inhibit handling for AVIC; make it per-vCPU so that KVM doesn't prematurely re-enable AVIC if multiple vCPUs have to-be-injected IRQs - Clean up and optimize the OSVW handling, avoiding a bug in which KVM would overwrite state when enabling virtualization on multiple CPUs in parallel. This should not be a problem because OSVW should usually be the same for all CPUs - Drop a WARN in KVM_MEMORY_ENCRYPT_REG_REGION where KVM complains about a "too large" size based purely on user input - Clean up and harden the pinning code for KVM_MEMORY_ENCRYPT_REG_REGION - Disallow synchronizing a VMSA of an already-launched/encrypted vCPU, as doing so for an SNP guest will crash the host due to an RMP violation page fault - Overhaul KVM's APIs for detecting SEV+ guests so that VM-scoped queries are required to hold kvm->lock, and enforce it by lockdep. Fix various bugs where sev_guest() was not ensured to be stable for the whole duration of a function or ioctl - Convert a pile of kvm->lock SEV code to guard() - Play nicer with userspace that does not enable KVM_CAP_EXCEPTION_PAYLOAD, for which KVM needs to set CR2 and DR6 as a response to ioctls such as KVM_GET_VCPU_EVENTS (even if the payload would end up in EXITINFO2 rather than CR2, for example). Only set CR2 and DR6 when consumption of the payload is imminent, but on the other hand force delivery of the payload in all paths where userspace retrieves CR2 or DR6 - Use vcpu->arch.cr2 when updating vmcb12's CR2 on nested #VMEXIT instead of vmcb02->save.cr2. The value is out of sync after a save/restore or after a #PF is injected into L2 - Fix a class of nSVM bugs where some fields written by the CPU are not synchronized from vmcb02 to cached vmcb12 after VMRUN, and so are not up-to-date when saved by KVM_GET_NESTED_STATE - Fix a class of bugs where the ordering between KVM_SET_NESTED_STATE and KVM_SET_{S}REGS could cause vmcb02 to be incorrectly initialized after save+restore - Add a variety of missing nSVM consistency checks - Fix several bugs where KVM failed to correctly update VMCB fields on nested #VMEXIT - Fix several bugs where KVM failed to correctly synthesize #UD or #GP for SVM-related instructions - Add support for save+restore of virtualized LBRs (on SVM) - Refactor various helpers and macros to improve clarity and (hopefully) make the code easier to maintain - Aggressively sanitize fields when copying from vmcb12, to guard against unintentionally allowing L1 to utilize yet-to-be-defined features - Fix several bugs where KVM botched rAX legality checks when emulating SVM instructions. There are remaining issues in that KVM doesn't handle size prefix overrides for 64-bit guests - Fail emulation of VMRUN/VMLOAD/VMSAVE if mapping vmcb12 fails instead of somewhat arbitrarily synthesizing #GP (i.e. don't double down on AMD's architectural but sketchy behavior of generating #GP for "unsupported" addresses) - Cache all used vmcb12 fields to further harden against TOCTOU bugs x86 (Intel): - Drop obsolete branch hint prefixes from the VMX instruction macros - Use ASM_INPUT_RM() in __vmcs_writel() to coerce clang into using a register input when appropriate - Code cleanups guest_memfd: - Don't mark guest_memfd folios as accessed, as guest_memfd doesn't support reclaim, the memory is unevictable, and there is no storage to write back to LoongArch selftests: - Add KVM PMU test cases s390 selftests: - Enable more memory selftests x86 selftests: - Add support for Hygon CPUs in KVM selftests - Fix a bug in the MSR test where it would get false failures on AMD/Hygon CPUs with exactly one of RDPID or RDTSCP - Add an MADV_COLLAPSE testcase for guest_memfd as a regression test for a bug where the kernel would attempt to collapse guest_memfd folios against KVM's will" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (373 commits) KVM: x86: use inlines instead of macros for is_sev_*guest x86/virt: Treat SVM as unsupported when running as an SEV+ guest KVM: SEV: Goto an existing error label if charging misc_cg for an ASID fails KVM: SVM: Move lock-protected allocation of SEV ASID into a separate helper KVM: SEV: use mutex guard in snp_handle_guest_req() KVM: SEV: use mutex guard in sev_mem_enc_unregister_region() KVM: SEV: use mutex guard in sev_mem_enc_ioctl() KVM: SEV: use mutex guard in snp_launch_update() KVM: SEV: Assert that kvm->lock is held when querying SEV+ support KVM: SEV: Document that checking for SEV+ guests when reclaiming memory is "safe" KVM: SEV: Hide "struct kvm_sev_info" behind CONFIG_KVM_AMD_SEV=y KVM: SEV: WARN on unhandled VM type when initializing VM KVM: LoongArch: selftests: Add PMU overflow interrupt test KVM: LoongArch: selftests: Add basic PMU event counting test KVM: LoongArch: selftests: Add cpucfg read/write helpers LoongArch: KVM: Add DMSINTC inject msi to vCPU LoongArch: KVM: Add DMSINTC device support LoongArch: KVM: Make vcpu_is_preempted() as a macro rather than function LoongArch: KVM: Move host CSR_GSTAT save and restore in context switch LoongArch: KVM: Move host CSR_EENTRY save and restore in context switch ...

tracing/osnoise: Add option to align tlat threads

2026-04-16T14:42:30+00:00

Add an option called TIMERLAT_ALIGN to osnoise/options, together with a corresponding setting osnoise/timerlat_align_us. This option sets the alignment of wakeup times between different timerlat threads, similarly to cyclictest's -A/--aligned option. If TIMERLAT_ALIGN is set, the first thread that reaches the first cycle records its first wake-up time. Each following thread sets its first wake-up time to a fixed offset from the recorded time, and increments it by the same offset. Example: osnoise/timerlat_period is set to 1000, osnoise/timerlat_align_us is set to 20. There are four threads, on CPUs 1 to 4. - CPU 4 enters first cycle first. The current time is 20000us, so the wake-up of the first cycle is set to 21000us. This time is recorded. - CPU 2 enter first cycle next. It reads the recorded time, increments it to 21020us, and uses this value as its own wake-up time for the first cycle. - CPU 3 enters first cycle next. It reads the recorded time, increments it to 21040 us, and uses the value as its own wake-up time. - CPU 1 proceeds analogically. In each next cycle, the wake-up time (called "absolute period" in timerlat code) is incremented by the (relative) period of 1000us. Thus, the wake-ups in the following cycles (provided the times are reached and not in the past) will be as follows: CPU 1 CPU 2 CPU 3 CPU 4 21080us 21020us 21040us 21000us 22080us 22020us 22040us 22000us ... ... ... ... Even if any cycle is skipped due to e.g. the first cycle calculation happening later, the alignment stays in place. Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: John Kacur Cc: Luis Goncalves Cc: Costa Shulyupin Link: https://patch.msgid.link/20260416115942.544032-1-tglozar@redhat.com Signed-off-by: Tomas Glozar Reviewed-by: Wander Lairson Costa Reviewed-by: Crystal Wood Signed-off-by: Steven Rostedt (Google)

Merge tag 'trace-rv-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2026-04-16T00:15:18+00:00

Pull runtime verification updates from Steven Rostedt: - Refactor da_monitor header to share handlers across monitor types No functional changes, only less code duplication. - Add Hybrid Automata model class Add a new model class that extends deterministic automata by adding constraints on transitions and states. Those constraints can take into account wall-clock time and as such allow RV monitor to make assertions on real time. Add documentation and code generation scripts. - Add stall monitor as hybrid automaton example Add a monitor that triggers a violation when a task is stalling as an example of automaton working with real time variables. - Convert the opid monitor to a hybrid automaton The opid monitor can be heavily simplified if written as a hybrid automaton: instead of tracking preempt and interrupt enable/disable events, it can just run constraints on the preemption/interrupt states when events like wakeup and need_resched verify. - Add support for per-object monitors in DA/HA Allow writing deterministic and hybrid automata monitors for generic objects (e.g. any struct), by exploiting a hash table where objects are saved. This allows to track more than just tasks in RV. For instance it will be used to track deadline entities in deadline monitors. - Add deadline tracepoints and move some deadline utilities Prepare the ground for deadline monitors by defining events and exporting helpers. - Add nomiss deadline monitor Add first example of deadline monitor asserting all entities complete before their deadline. - Improve rvgen error handling Introduce AutomataError exception class and better handle expected exceptions while showing a backtrace for unexpected ones. - Improve python code quality in rvgen Refactor the rvgen generation scripts to align with python best practices: use f-strings instead of %, use len() instead of __len__(), remove semicolons, use context managers for file operations, fix whitespace violations, extract magic strings into constants, remove unused imports and methods. - Fix small bugs in rvgen The generator scripts presented some corner case bugs: logical error in validating what a correct dot file looks like, fix an isinstance() check, enforce a dot file has an initial state, fix type annotations and typos in comments. - rvgen refactoring Refactor automata.py to use iterator-based parsing and handle required arguments directly in argparse. - Allow epoll in rtapp-sleep monitor The epoll_wait call is now rt-friendly so it should be allowed in the sleep monitor as a valid sleep method. * tag 'trace-rv-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (32 commits) rv: Allow epoll in rtapp-sleep monitor rv/rvgen: fix _fill_states() return type annotation rv/rvgen: fix unbound loop variable warning rv/rvgen: enforce presence of initial state rv/rvgen: extract node marker string to class constant rv/rvgen: fix isinstance check in Variable.expand() rv/rvgen: make monitor arguments required in rvgen rv/rvgen: remove unused __get_main_name method rv/rvgen: remove unused sys import from dot2c rv/rvgen: refactor automata.py to use iterator-based parsing rv/rvgen: use class constant for init marker rv/rvgen: fix DOT file validation logic error rv/rvgen: fix PEP 8 whitespace violations rv/rvgen: fix typos in automata and generator docstring and comments rv/rvgen: use context managers for file operations rv/rvgen: remove unnecessary semicolons rv/rvgen: replace __len__() calls with len() rv/rvgen: replace % string formatting with f-strings rv/rvgen: remove bare except clauses in generator rv/rvgen: introduce AutomataError exception class ...

Merge tag 'trace-ringbuffer-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2026-04-15T22:59:46+00:00

Pull ring-buffer updates from Steven Rostedt: - Add remote buffers for pKVM pKVM has a hypervisor component that is used to protect the guest from the host kernel. This hypervisor is a black box to the kernel as the kernel is to user space. The remote buffers are used to have a memory mapping between the hypervisor and the kernel where kernel may send commands to enable tracing within the hypervisor. Then the kernel will read this memory mapping just like user space can read the memory mapped ring buffer of the kernel tracing system. Since the hypervisor only has a single context, it doesn't need to worry about races between normal context, interrupt context and NMIs like the kernel does. The ring buffer it uses doesn't need to be as complex. The remote buffers are a simple version of the ring buffer that works in a single context. They are still per-CPU and use sub buffers. The data layout is the same as the kernel's ring buffer to share the same parsing. Currently, only ARM64 implements pKVM, but there's work to implement it also in x86. The remote buffer code is separated out from the ARM implementation so that it can be used in the future by x86. The ARM64 updates for pKVM is in the ARM/KVM tree and it merged in the remote buffers of this tree. - Make the backup instance non reusable The backup instance is a copy of the persistent ring buffer so that the persistent ring buffer could start recording again without using the data from the previous boot. The backup isn't for normal tracing. It is made read-only, and after it is consumed, it is automatically removed. - Have backup copy persistent instance before it starts recording To allow the persistent ring buffer to start recording from the kernel command line commands, move the copy of the backup instance to before the the command line options start recording. - Report header_page overwrite field as "char" and not "int' The rust parser of the header_page file was triggering a warning when it defined the overwrite variable as "int" but it was only a single byte in size. - Fix memory barriers for the trace_buffer CPU mask When a CPU comes online, the bit is set to allow readers to know that the CPU buffer is allocated. The bit is set after the allocation is done, and a smp_wmb() is performed after the allocation and before the setting of the bit. But instead of adding a smp_rmb() to all readers, since once a buffer is created for a CPU it is not deleted if that CPU goes offline, so this allocation is almost always done at boot up before any readers exist. If for the unlikely case where a CPU comes online for the first time after the system boot has finished, send an IPI to all CPUs to force the smp_rmb() for each CPU. - Show clock function being used in debugging ring buffer data When the ring buffer checks are enabled and the ring buffer detects an inconsistency in the times of the invents, print out the clock being used when the error occurred. There was a very hard to hit bug that would happen every so often and it ended up being only triggered when the jiffies clock was being used. If the bug showed the clock being used, it would have been much easier to find the problem (which was an internal function was being traced which caused the clock accounting to go off). * tag 'trace-ringbuffer-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (26 commits) ring-buffer: Prevent off-by-one array access in ring_buffer_desc_page() ring-buffer: Report header_page overwrite as char tracing: Allow backup to save persistent ring buffer before it starts tracing/Documentation: Add a section about backup instance tracing: Remove the backup instance automatically after read tracing: Make the backup instance non-reusable ring-buffer: Enforce read ordering of trace_buffer cpumask and buffers ring-buffer: Show what clock function is used on timestamp errors tracing: Check for undefined symbols in simple_ring_buffer tracing: load/unload page callbacks for simple_ring_buffer Documentation: tracing: Add tracing remotes tracing: selftests: Add trace remote tests tracing: Add a trace remote module for testing tracing: Introduce simple_ring_buffer ring-buffer: Export buffer_data_page and macros tracing: Add helpers to create trace remote events tracing: Add events/ root files to trace remotes tracing: Add events to trace remotes tracing: Add init callback to trace remotes tracing: Add non-consuming read to trace remotes ...

Merge tag 'ftrace-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2026-04-15T22:57:11+00:00

Pull ftrace update from Steven Rostedt: - Speed up ftrace_lookup_symbols() for single lookups The kallsyms lookup in ftrace_lookup_symbols() does a linear search over each symbol. This is fine when it must match multiple strings, but when there's only a single string being searched for, using a binary search is much more efficient. When a single string is passed in to search, use the binary search method. * tag 'ftrace-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ftrace: Use kallsyms binary search for single-symbol lookup

Merge tag 'bpf-next-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

2026-04-15T01:04:04+00:00

Pull bpf updates from Alexei Starovoitov: - Welcome new BPF maintainers: Kumar Kartikeya Dwivedi, Eduard Zingerman while Martin KaFai Lau reduced his load to Reviwer. - Lots of fixes everywhere from many first time contributors. Thank you All. - Diff stat is dominated by mechanical split of verifier.c into multiple components: - backtrack.c: backtracking logic and jump history - states.c: state equivalence - cfg.c: control flow graph, postorder, strongly connected components - liveness.c: register and stack liveness - fixups.c: post-verification passes: instruction patching, dead code removal, bpf_loop inlining, finalize fastcall 8k line were moved. verifier.c still stands at 20k lines. Further refactoring is planned for the next release. - Replace dynamic stack liveness with static stack liveness based on data flow analysis. This improved the verification time by 2x for some programs and equally reduced memory consumption. New logic is in liveness.c and supported by constant folding in const_fold.c (Eduard Zingerman, Alexei Starovoitov) - Introduce BTF layout to ease addition of new BTF kinds (Alan Maguire) - Use kmalloc_nolock() universally in BPF local storage (Amery Hung) - Fix several bugs in linked registers delta tracking (Daniel Borkmann) - Improve verifier support of arena pointers (Emil Tsalapatis) - Improve verifier tracking of register bounds in min/max and tnum domains (Harishankar Vishwanathan, Paul Chaignon, Hao Sun) - Further extend support for implicit arguments in the verifier (Ihor Solodrai) - Add support for nop,nop5 instruction combo for USDT probes in libbpf (Jiri Olsa) - Support merging multiple module BTFs (Josef Bacik) - Extend applicability of bpf_kptr_xchg (Kaitao Cheng) - Retire rcu_trace_implies_rcu_gp() (Kumar Kartikeya Dwivedi) - Support variable offset context access for 'syscall' programs (Kumar Kartikeya Dwivedi) - Migrate bpf_task_work and dynptr to kmalloc_nolock() (Mykyta Yatsenko) - Fix UAF in in open-coded task_vma iterator (Puranjay Mohan) * tag 'bpf-next-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (241 commits) selftests/bpf: cover short IPv4/IPv6 inputs with adjust_room bpf: reject short IPv4/IPv6 inputs in bpf_prog_test_run_skb selftests/bpf: Use memfd_create instead of shm_open in cgroup_iter_memcg selftests/bpf: Add test for cgroup storage OOB read bpf: Fix OOB in pcpu_init_value selftests/bpf: Fix reg_bounds to match new tnum-based refinement selftests/bpf: Add tests for non-arena/arena operations bpf: Allow instructions with arena source and non-arena dest registers bpftool: add missing fsession to the usage and docs of bpftool docs/bpf: add missing fsession attach type to docs bpf: add missing fsession to the verifier log bpf: Move BTF checking logic into check_btf.c bpf: Move backtracking logic to backtrack.c bpf: Move state equivalence logic to states.c bpf: Move check_cfg() into cfg.c bpf: Move compute_insn_live_regs() into liveness.c bpf: Move fixup/post-processing logic from verifier.c into fixups.c bpf: Simplify do_check_insn() bpf: Move checks for reserved fields out of the main pass bpf: Delete unused variable ...

Merge tag 'timers-core-2026-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2026-04-14T17:27:07+00:00

Pull timer core updates from Thomas Gleixner: - A rework of the hrtimer subsystem to reduce the overhead for frequently armed timers, especially the hrtick scheduler timer: - Better timer locality decision - Simplification of the evaluation of the first expiry time by keeping track of the neighbor timers in the RB-tree by providing a RB-tree variant with neighbor links. That avoids walking the RB-tree on removal to find the next expiry time, but even more important allows to quickly evaluate whether a timer which is rearmed changes the position in the RB-tree with the modified expiry time or not. If not, the dequeue/enqueue sequence which both can end up in rebalancing can be completely avoided. - Deferred reprogramming of the underlying clock event device. This optimizes for the situation where a hrtimer callback sets the need resched bit. In that case the code attempts to defer the re-programming of the clock event device up to the point where the scheduler has picked the next task and has the next hrtick timer armed. In case that there is no immediate reschedule or soft interrupts have to be handled before reaching the reschedule point in the interrupt entry code the clock event is reprogrammed in one of those code paths to prevent that the timer becomes stale. - Support for clocksource coupled clockevents The TSC deadline timer is coupled to the TSC. The next event is programmed in TSC time. Currently this is done by converting the CLOCK_MONOTONIC based expiry value into a relative timeout, converting it into TSC ticks, reading the TSC adding the delta ticks and writing the deadline MSR. As the timekeeping core has the conversion factors for the TSC already, the whole back and forth conversion can be completely avoided. The timekeeping core calculates the reverse conversion factors from nanoseconds to TSC ticks and utilizes the base timestamps of TSC and CLOCK_MONOTONIC which are updated once per tick. This allows a direct conversion into the TSC deadline value without reading the time and as a bonus keeps the deadline conversion in sync with the TSC conversion factors, which are updated by adjtimex() on systems with NTP/PTP enabled. - Allow inlining of the clocksource read and clockevent write functions when they are tiny enough, e.g. on x86 RDTSC and WRMSR. With all those enhancements in place a hrtick enabled scheduler provides the same performance as without hrtick. But also other hrtimer users obviously benefit from these optimizations. - Robustness improvements and cleanups of historical sins in the hrtimer and timekeeping code. - Rewrite of the clocksource watchdog. The clocksource watchdog code has over time reached the state of an impenetrable maze of duct tape and staples. The original design, which was made in the context of systems far smaller than today, is based on the assumption that the to be monitored clocksource (TSC) can be trivially compared against a known to be stable clocksource (HPET/ACPI-PM timer). Over the years this rather naive approach turned out to have major flaws. Long delays between the watchdog invocations can cause wrap arounds of the reference clocksource. The access to the reference clocksource degrades on large multi-sockets systems dure to interconnect congestion. This has been addressed with various heuristics which degraded the accuracy of the watchdog to the point that it fails to detect actual TSC problems on older hardware which exposes slow inter CPU drifts due to firmware manipulating the TSC to hide SMI time. The rewrite addresses this by: - Restricting the validation against the reference clocksource to the boot CPU which is usually closest to the legacy block which contains the reference clocksource (HPET/ACPI-PM). - Do a round robin validation betwen the boot CPU and the other CPUs based only on the TSC with an algorithm similar to the TSC synchronization code during CPU hotplug. - Being more leniant versus remote timeouts - The usual tiny fixes, cleanups and enhancements all over the place * tag 'timers-core-2026-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (75 commits) alarmtimer: Access timerqueue node under lock in suspend hrtimer: Fix incorrect #endif comment for BITS_PER_LONG check posix-timers: Fix stale function name in comment timers: Get this_cpu once while clearing the idle state clocksource: Rewrite watchdog code completely clocksource: Don't use non-continuous clocksources as watchdog x86/tsc: Handle CLOCK_SOURCE_VALID_FOR_HRES correctly MIPS: Don't select CLOCKSOURCE_WATCHDOG parisc: Remove unused clocksource flags hrtimer: Add a helper to retrieve a hrtimer from its timerqueue node hrtimer: Remove trailing comma after HRTIMER_MAX_CLOCK_BASES hrtimer: Mark index and clockid of clock base as const hrtimer: Drop unnecessary pointer indirection in hrtimer_expire_entry event hrtimer: Drop spurious space in 'enum hrtimer_base_type' hrtimer: Don't zero-initialize ret in hrtimer_nanosleep() hrtimer: Remove hrtimer_get_expires_ns() timekeeping: Mark offsets array as const timekeeping/auxclock: Consistently use raw timekeeper for tk_setup_internals() timer_list: Print offset as signed integer tracing: Use explicit array size instead of sentinel elements in symbol printing ...