selftests/bpf: Add a test for objects stuck in free_by_rcu_ttracegrafted

Delete all elements of BPF_F_NO_PREALLOC hash map in one batch. The first
free_bulk() starts RCU tasks trace GP and the rest of the elements are
freed while it's in flight. Wait for call_rcu_ttrace_in_progress to clear
in bpf_mem_cache of every cpu and check that free_by_rcu_ttrace and
waiting_for_gp_ttrace lists are empty.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20260930095920.601738-4-alexei.starovoitov@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/scripts/dtc/Makefile b/scripts/dtc/Makefile
new file mode 100644
index 000000000..b47f4daa4
--- /dev/null
+++ b/scripts/dtc/Makefile
@@ -0,0 +1,27 @@
+# SPDX-License-Identifier: GPL-2.0
+# scripts/dtc makefile
+
+# *** Also keep .gitignore in sync when changing ***
+hostprogs-always-$(CONFIG_DTC)		+= dtc fdtoverlay
+hostprogs-always-$(CHECK_DTBS)		+= dtc
+
+dtc-objs	:= dtc.o flattree.o fstree.o data.o livetree.o treesource.o \
+		   srcpos.o checks.o util.o
+dtc-objs	+= dtc-lexer.lex.o dtc-parser.tab.o
+
+# The upstream project builds libfdt as a separate library.  We are choosing to
+# instead directly link the libfdt object files into fdtoverlay.
+libfdt-objs	:= fdt.o fdt_ro.o fdt_wip.o fdt_sw.o fdt_rw.o fdt_strerror.o fdt_empty_tree.o fdt_addresses.o fdt_overlay.o
+libfdt		= $(addprefix libfdt/,$(libfdt-objs))
+fdtoverlay-objs	:= $(libfdt) fdtoverlay.o util.o
+
+# Source files need to get at the userspace version of libfdt_env.h to compile
+HOST_EXTRACFLAGS += -I $(src)/libfdt
+HOST_EXTRACFLAGS += -DNO_YAML
+
+# Generated files need one more search path to include headers in source tree
+HOSTCFLAGS_dtc-lexer.lex.o := -I $(src)
+HOSTCFLAGS_dtc-parser.tab.o := -I $(src)
+
+# dependencies on generated files need to be listed explicitly
+$(obj)/dtc-lexer.lex.o: $(obj)/dtc-parser.tab.h