workqueue: skip the node_nr_active update for non-unbound workqueuesgrafted

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 <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 93 insertions, 0 deletions

diff --git a/samples/bpf/tracex5.bpf.c b/samples/bpf/tracex5.bpf.c
new file mode 100644
index 000000000..4d3d6c9b2
--- /dev/null
+++ b/samples/bpf/tracex5.bpf.c
@@ -0,0 +1,93 @@
+/* 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 "syscall_nrs.h"
+#include <linux/version.h>
+#include <uapi/linux/unistd.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_core_read.h>
+
+#define __stringify(x) #x
+#define PROG(F) SEC("kprobe/"__stringify(F)) int bpf_func_##F
+
+struct {
+	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
+	__uint(key_size, sizeof(u32));
+	__uint(value_size, sizeof(u32));
+#ifdef __mips__
+	__uint(max_entries, 6000); /* MIPS n64 syscalls start at 5000 */
+#else
+	__uint(max_entries, 1024);
+#endif
+} progs SEC(".maps");
+
+SEC("kprobe/__seccomp_filter")
+int bpf_prog1(struct pt_regs *ctx)
+{
+	int sc_nr = (int)PT_REGS_PARM1(ctx);
+
+	/* dispatch into next BPF program depending on syscall number */
+	bpf_tail_call(ctx, &progs, sc_nr);
+
+	/* fall through -> unknown syscall */
+	if (sc_nr >= __NR_getuid && sc_nr <= __NR_getsid) {
+		char fmt[] = "syscall=%d (one of get/set uid/pid/gid)\n";
+		bpf_trace_printk(fmt, sizeof(fmt), sc_nr);
+	}
+	return 0;
+}
+
+/* we jump here when syscall number == __NR_write */
+PROG(SYS__NR_write)(struct pt_regs *ctx)
+{
+	struct seccomp_data sd;
+
+	bpf_core_read(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx));
+	if (sd.args[2] == 512) {
+		char fmt[] = "write(fd=%d, buf=%p, size=%d)\n";
+		bpf_trace_printk(fmt, sizeof(fmt),
+				 sd.args[0], sd.args[1], sd.args[2]);
+	}
+	return 0;
+}
+
+PROG(SYS__NR_read)(struct pt_regs *ctx)
+{
+	struct seccomp_data sd;
+
+	bpf_core_read(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx));
+	if (sd.args[2] > 128 && sd.args[2] <= 1024) {
+		char fmt[] = "read(fd=%d, buf=%p, size=%d)\n";
+		bpf_trace_printk(fmt, sizeof(fmt),
+				 sd.args[0], sd.args[1], sd.args[2]);
+	}
+	return 0;
+}
+
+#ifdef __NR_mmap2
+PROG(SYS__NR_mmap2)(struct pt_regs *ctx)
+{
+	char fmt[] = "mmap2\n";
+
+	bpf_trace_printk(fmt, sizeof(fmt));
+	return 0;
+}
+#endif
+
+#ifdef __NR_mmap
+PROG(SYS__NR_mmap)(struct pt_regs *ctx)
+{
+	char fmt[] = "mmap\n";
+
+	bpf_trace_printk(fmt, sizeof(fmt));
+	return 0;
+}
+#endif
+
+char _license[] SEC("license") = "GPL";
+u32 _version SEC("version") = LINUX_VERSION_CODE;