user/sven/linux.git/kernel/events/core.c, branch v6.12.10

perf: Fix missing RCU reader protection in perf_event_clear_cpumask()

2024-10-23T18:52:25Z

Running rcutorture scenario TREE05, the below warning is triggered. [ 32.604594] WARNING: suspicious RCU usage [ 32.605928] 6.11.0-rc5-00040-g4ba4f1afb6a9 #55238 Not tainted [ 32.607812] ----------------------------- [ 32.609140] kernel/events/core.c:13946 RCU-list traversed in non-reader section!! [ 32.611595] other info that might help us debug this: [ 32.614247] rcu_scheduler_active = 2, debug_locks = 1 [ 32.616392] 3 locks held by cpuhp/4/35: [ 32.617687] #0: ffffffffb666a650 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x4e/0x200 [ 32.620563] #1: ffffffffb666cd20 (cpuhp_state-down){+.+.}-{0:0}, at: cpuhp_thread_fun+0x4e/0x200 [ 32.623412] #2: ffffffffb677c288 (pmus_lock){+.+.}-{3:3}, at: perf_event_exit_cpu_context+0x32/0x2f0 In perf_event_clear_cpumask(), uses list_for_each_entry_rcu() without an obvious RCU read-side critical section. Either pmus_srcu or pmus_lock is good enough to protect the pmus list. In the current context, pmus_lock is already held. The list_for_each_entry_rcu() is not required. Fixes: 4ba4f1afb6a9 ("perf: Generic hotplug support for a PMU with a scope") Closes: https://lore.kernel.org/lkml/2b66dff8-b827-494b-b151-1ad8d56f13e6@paulmck-laptop/ Closes: https://lore.kernel.org/oe-lkp/202409131559.545634cc-oliver.sang@intel.com Reported-by: "Paul E. McKenney" Reported-by: kernel test robot Suggested-by: Peter Zijlstra Signed-off-by: Kan Liang Signed-off-by: Peter Zijlstra (Intel) Tested-by: "Paul E. McKenney" Link: https://lore.kernel.org/r/20240913162340.2142976-1-kan.liang@linux.intel.com

sched/fair: Fix external p->on_rq users

2024-10-14T07:14:35Z

Sean noted that ever since commit 152e11f6df29 ("sched/fair: Implement delayed dequeue") KVM's preemption notifiers have started mis-classifying preemption vs blocking. Notably p->on_rq is no longer sufficient to determine if a task is runnable or blocked -- the aforementioned commit introduces tasks that remain on the runqueue even through they will not run again, and should be considered blocked for many cases. Add the task_is_runnable() helper to classify things and audit all external users of the p->on_rq state. Also add a few comments. Fixes: 152e11f6df29 ("sched/fair: Implement delayed dequeue") Reported-by: Sean Christopherson Tested-by: Sean Christopherson Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://lkml.kernel.org/r/20241010091843.GK33184@noisy.programming.kicks-ass.net

[tree-wide] finally take no_llseek out

2024-09-27T15:18:43Z

no_llseek had been defined to NULL two years ago, in commit 868941b14441 ("fs: remove no_llseek") To quote that commit, At -rc1 we'll need do a mechanical removal of no_llseek - git grep -l -w no_llseek | grep -v porting.rst | while read i; do sed -i '/\/d' $i done would do it. Unfortunately, that hadn't been done. Linus, could you do that now, so that we could finally put that thing to rest? All instances are of the form .llseek = no_llseek, so it's obviously safe. Signed-off-by: Al Viro Signed-off-by: Linus Torvalds

Merge tag 'pull-stable-struct_fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2024-09-23T16:35:36Z

Pull 'struct fd' updates from Al Viro: "Just the 'struct fd' layout change, with conversion to accessor helpers" * tag 'pull-stable-struct_fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: add struct fd constructors, get rid of __to_fd() struct fd: representation change introduce fd_file(), convert all accessors to it.

perf: Fix topology_sibling_cpumask check warning on ARM

2024-09-22T16:03:22Z

The below warning is triggered when building with arm multi_v7_defconfig. kernel/events/core.c: In function 'perf_event_setup_cpumask': kernel/events/core.c:14012:13: warning: the comparison will always evaluate as 'true' for the address of 'thread_sibling' will never be NULL [-Waddress] 14012 | if (!topology_sibling_cpumask(cpu)) { The perf_event_init_cpu() may be invoked at the early boot stage, while the topology_*_cpumask hasn't been initialized yet. The check is to specially handle the case, and initialize the perf_online__masks on the boot CPU. X86 uses a per-cpu cpumask pointer, which could be NULL at the early boot stage. However, ARM uses a global variable, which never be NULL. Use perf_online_mask as an indicator instead. Only initialize the perf_online__masks when perf_online_mask is empty. Fix a typo as well. Fixes: 4ba4f1afb6a9 ("perf: Generic hotplug support for a PMU with a scope") Reported-by: Stephen Rothwell Closes: https://lore.kernel.org/lkml/20240911153854.240bbc1f@canb.auug.org.au/ Reported-by: Steven Price Closes: https://lore.kernel.org/lkml/1835eb6d-3e05-47f3-9eae-507ce165c3bf@arm.com/ Signed-off-by: Kan Liang Tested-by: Steven Price Signed-off-by: Linus Torvalds

Merge tag 'bpf-next-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

2024-09-21T16:27:50Z

Pull bpf updates from Alexei Starovoitov: - Introduce '__attribute__((bpf_fastcall))' for helpers and kfuncs with corresponding support in LLVM. It is similar to existing 'no_caller_saved_registers' attribute in GCC/LLVM with a provision for backward compatibility. It allows compilers generate more efficient BPF code assuming the verifier or JITs will inline or partially inline a helper/kfunc with such attribute. bpf_cast_to_kern_ctx, bpf_rdonly_cast, bpf_get_smp_processor_id are the first set of such helpers. - Harden and extend ELF build ID parsing logic. When called from sleepable context the relevants parts of ELF file will be read to find and fetch .note.gnu.build-id information. Also harden the logic to avoid TOCTOU, overflow, out-of-bounds problems. - Improvements and fixes for sched-ext: - Allow passing BPF iterators as kfunc arguments - Make the pointer returned from iter_next method trusted - Fix x86 JIT convergence issue due to growing/shrinking conditional jumps in variable length encoding - BPF_LSM related: - Introduce few VFS kfuncs and consolidate them in fs/bpf_fs_kfuncs.c - Enforce correct range of return values from certain LSM hooks - Disallow attaching to other LSM hooks - Prerequisite work for upcoming Qdisc in BPF: - Allow kptrs in program provided structs - Support for gen_epilogue in verifier_ops - Important fixes: - Fix uprobe multi pid filter check - Fix bpf_strtol and bpf_strtoul helpers - Track equal scalars history on per-instruction level - Fix tailcall hierarchy on x86 and arm64 - Fix signed division overflow to prevent INT_MIN/-1 trap on x86 - Fix get kernel stack in BPF progs attached to tracepoint:syscall - Selftests: - Add uprobe bench/stress tool - Generate file dependencies to drastically improve re-build time - Match JIT-ed and BPF asm with __xlated/__jited keywords - Convert older tests to test_progs framework - Add support for RISC-V - Few fixes when BPF programs are compiled with GCC-BPF backend (support for GCC-BPF in BPF CI is ongoing in parallel) - Add traffic monitor - Enable cross compile and musl libc * tag 'bpf-next-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (260 commits) btf: require pahole 1.21+ for DEBUG_INFO_BTF with default DWARF version btf: move pahole check in scripts/link-vmlinux.sh to lib/Kconfig.debug btf: remove redundant CONFIG_BPF test in scripts/link-vmlinux.sh bpf: Call the missed kfree() when there is no special field in btf bpf: Call the missed btf_record_free() when map creation fails selftests/bpf: Add a test case to write mtu result into .rodata selftests/bpf: Add a test case to write strtol result into .rodata selftests/bpf: Rename ARG_PTR_TO_LONG test description selftests/bpf: Fix ARG_PTR_TO_LONG {half-,}uninitialized test bpf: Zero former ARG_PTR_TO_{LONG,INT} args in case of error bpf: Improve check_raw_mode_ok test for MEM_UNINIT-tagged types bpf: Fix helper writes to read-only maps bpf: Remove truncation test in bpf_strtol and bpf_strtoul helpers bpf: Fix bpf_strtol and bpf_strtoul helpers for 32bit selftests/bpf: Add tests for sdiv/smod overflow cases bpf: Fix a sdiv overflow issue libbpf: Add bpf_object__token_fd accessor docs/bpf: Add missing BPF program types to docs docs/bpf: Add constant values for linkages bpf: Use fake pt_regs when doing bpf syscall tracepoint tracing ...

Merge tag 'perf-core-2024-09-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2024-09-18T13:03:58Z

Pull perf events updates from Ingo Molnar: - Implement per-PMU context rescheduling to significantly improve single-PMU performance, and related cleanups/fixes (Peter Zijlstra and Namhyung Kim) - Fix ancient bug resulting in a lot of events being dropped erroneously at higher sampling frequencies (Luo Gengkun) - uprobes enhancements: - Implement RCU-protected hot path optimizations for better performance: "For baseline vs SRCU, peak througput increased from 3.7 M/s (million uprobe triggerings per second) up to about 8 M/s. For uretprobes it's a bit more modest with bump from 2.4 M/s to 5 M/s. For SRCU vs RCU Tasks Trace, peak throughput for uprobes increases further from 8 M/s to 10.3 M/s (+28%!), and for uretprobes from 5.3 M/s to 5.8 M/s (+11%), as we have more work to do on uretprobes side. Even single-thread (no contention) performance is slightly better: 3.276 M/s to 3.396 M/s (+3.5%) for uprobes, and 2.055 M/s to 2.174 M/s (+5.8%) for uretprobes." (Andrii Nakryiko et al) - Document mmap_lock, don't abuse get_user_pages_remote() (Oleg Nesterov) - Cleanups & fixes to prepare for future work: - Remove uprobe_register_refctr() - Simplify error handling for alloc_uprobe() - Make uprobe_register() return struct uprobe * - Fold __uprobe_unregister() into uprobe_unregister() - Shift put_uprobe() from delete_uprobe() to uprobe_unregister() - BPF: Fix use-after-free in bpf_uprobe_multi_link_attach() (Oleg Nesterov) - New feature & ABI extension: allow events to use PERF_SAMPLE READ with inheritance, enabling sample based profiling of a group of counters over a hierarchy of processes or threads (Ben Gainey) - Intel uncore & power events updates: - Add Arrow Lake and Lunar Lake support - Add PERF_EV_CAP_READ_SCOPE - Clean up and enhance cpumask and hotplug support (Kan Liang) - Add LNL uncore iMC freerunning support - Use D0:F0 as a default device (Zhenyu Wang) - Intel PT: fix AUX snapshot handling race (Adrian Hunter) - Misc fixes and cleanups (James Clark, Jiri Olsa, Oleg Nesterov and Peter Zijlstra) * tag 'perf-core-2024-09-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (40 commits) dmaengine: idxd: Clean up cpumask and hotplug for perfmon iommu/vt-d: Clean up cpumask and hotplug for perfmon perf/x86/intel/cstate: Clean up cpumask and hotplug perf: Add PERF_EV_CAP_READ_SCOPE perf: Generic hotplug support for a PMU with a scope uprobes: perform lockless SRCU-protected uprobes_tree lookup rbtree: provide rb_find_rcu() / rb_find_add_rcu() perf/uprobe: split uprobe_unregister() uprobes: travers uprobe's consumer list locklessly under SRCU protection uprobes: get rid of enum uprobe_filter_ctx in uprobe filter callbacks uprobes: protected uprobe lifetime with SRCU uprobes: revamp uprobe refcounting and lifetime management bpf: Fix use-after-free in bpf_uprobe_multi_link_attach() perf/core: Fix small negative period being ignored perf: Really fix event_function_call() locking perf: Optimize __pmu_ctx_sched_out() perf: Add context time freeze perf: Fix event_function_call() locking perf: Extract a few helpers perf: Optimize context reschedule for single PMU cases ...

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

2024-09-16T04:55:07Z

Pull arm64 updates from Will Deacon: "The highlights are support for Arm's "Permission Overlay Extension" using memory protection keys, support for running as a protected guest on Android as well as perf support for a bunch of new interconnect PMUs. Summary: ACPI: - Enable PMCG erratum workaround for HiSilicon HIP10 and 11 platforms. - Ensure arm64-specific IORT header is covered by MAINTAINERS. CPU Errata: - Enable workaround for hardware access/dirty issue on Ampere-1A cores. Memory management: - Define PHYSMEM_END to fix a crash in the amdgpu driver. - Avoid tripping over invalid kernel mappings on the kexec() path. - Userspace support for the Permission Overlay Extension (POE) using protection keys. Perf and PMUs: - Add support for the "fixed instruction counter" extension in the CPU PMU architecture. - Extend and fix the event encodings for Apple's M1 CPU PMU. - Allow LSM hooks to decide on SPE permissions for physical profiling. - Add support for the CMN S3 and NI-700 PMUs. Confidential Computing: - Add support for booting an arm64 kernel as a protected guest under Android's "Protected KVM" (pKVM) hypervisor. Selftests: - Fix vector length issues in the SVE/SME sigreturn tests - Fix build warning in the ptrace tests. Timers: - Add support for PR_{G,S}ET_TSC so that 'rr' can deal with non-determinism arising from the architected counter. Miscellaneous: - Rework our IPI-based CPU stopping code to try NMIs if regular IPIs don't succeed. - Minor fixes and cleanups" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (94 commits) perf: arm-ni: Fix an NULL vs IS_ERR() bug arm64: hibernate: Fix warning for cast from restricted gfp_t arm64: esr: Define ESR_ELx_EC_* constants as UL arm64: pkeys: remove redundant WARN perf: arm_pmuv3: Use BR_RETIRED for HW branch event if enabled MAINTAINERS: List Arm interconnect PMUs as supported perf: Add driver for Arm NI-700 interconnect PMU dt-bindings/perf: Add Arm NI-700 PMU perf/arm-cmn: Improve format attr printing perf/arm-cmn: Clean up unnecessary NUMA_NO_NODE check arm64/mm: use lm_alias() with addresses passed to memblock_free() mm: arm64: document why pte is not advanced in contpte_ptep_set_access_flags() arm64: Expose the end of the linear map in PHYSMEM_END arm64: trans_pgd: mark PTEs entries as valid to avoid dead kexec() arm64/mm: Delete __init region from memblock.reserved perf/arm-cmn: Support CMN S3 dt-bindings: perf: arm-cmn: Add CMN S3 perf/arm-cmn: Refactor DTC PMU register access perf/arm-cmn: Make cycle counts less surprising perf/arm-cmn: Improve build-time assertion ...

lib/buildid: rename build_id_parse() into build_id_parse_nofault()

2024-09-11T16:58:30Z

Make it clear that build_id_parse() assumes that it can take no page fault by renaming it and current few users to build_id_parse_nofault(). Also add build_id_parse() stub which for now falls back to non-sleepable implementation, but will be changed in subsequent patches to take advantage of sleepable context. PROCMAP_QUERY ioctl() on /proc//maps file is using build_id_parse() and will automatically take advantage of more reliable sleepable context implementation. Reviewed-by: Eduard Zingerman Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20240829174232.3133883-6-andrii@kernel.org Signed-off-by: Alexei Starovoitov

perf: Add PERF_EV_CAP_READ_SCOPE

2024-09-10T09:44:13Z

Usually, an event can be read from any CPU of the scope. It doesn't need to be read from the advertised CPU. Add a new event cap, PERF_EV_CAP_READ_SCOPE. An event of a PMU with scope can be read from any active CPU in the scope. Signed-off-by: Kan Liang Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20240802151643.1691631-3-kan.liang@linux.intel.com