From a5bde5d8fde8a8cb28e59a672d5ddc5b9c1e7656 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Wed, 5 Aug 2026 07:52:36 -0700 Subject: workqueue: skip the node_nr_active update for non-unbound workqueues apply_wqattrs_commit() updates node_nr_active->max unconditionally. wq->node_nr_active[] is only allocated for unbound workqueues, so guard the call before per-cpu workqueues start using this path. No functional change: only unbound workqueues reach apply_wqattrs_*() today. Signed-off-by: Breno Leitao Signed-off-by: Tejun Heo --- samples/bpf/tracex4.bpf.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 samples/bpf/tracex4.bpf.c (limited to 'samples/bpf/tracex4.bpf.c') diff --git a/samples/bpf/tracex4.bpf.c b/samples/bpf/tracex4.bpf.c new file mode 100644 index 000000000..d786492fd --- /dev/null +++ b/samples/bpf/tracex4.bpf.c @@ -0,0 +1,54 @@ +/* Copyright (c) 2015 PLUMgrid, http://plumgrid.com + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + */ +#include "vmlinux.h" +#include +#include +#include + +struct pair { + u64 val; + u64 ip; +}; + +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __type(key, long); + __type(value, struct pair); + __uint(max_entries, 1000000); +} my_map SEC(".maps"); + +/* kprobe is NOT a stable ABI. If kernel internals change this bpf+kprobe + * example will no longer be meaningful + */ +SEC("kprobe/kmem_cache_free") +int bpf_prog1(struct pt_regs *ctx) +{ + long ptr = PT_REGS_PARM2(ctx); + + bpf_map_delete_elem(&my_map, &ptr); + return 0; +} + +SEC("kretprobe/kmem_cache_alloc_node_noprof") +int bpf_prog2(struct pt_regs *ctx) +{ + long ptr = PT_REGS_RC(ctx); + long ip = 0; + + /* get ip address of kmem_cache_alloc_node_noprof() caller */ + BPF_KRETPROBE_READ_RET_IP(ip, ctx); + + struct pair v = { + .val = bpf_ktime_get_ns(), + .ip = ip, + }; + + bpf_map_update_elem(&my_map, &ptr, &v, BPF_ANY); + return 0; +} +char _license[] SEC("license") = "GPL"; +u32 _version SEC("version") = LINUX_VERSION_CODE; -- cgit v1.3.1