From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- scripts/Makefile.userprogs | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 scripts/Makefile.userprogs (limited to 'scripts/Makefile.userprogs') diff --git a/scripts/Makefile.userprogs b/scripts/Makefile.userprogs new file mode 100644 index 000000000..f3a7e1ef3 --- /dev/null +++ b/scripts/Makefile.userprogs @@ -0,0 +1,45 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# Build userspace programs for the target system +# + +# Executables compiled from a single .c file +user-csingle := $(foreach m, $(userprogs), $(if $($(m)-objs),,$(m))) + +# Executables linked based on several .o files +user-cmulti := $(foreach m, $(userprogs), $(if $($(m)-objs),$(m))) + +# Objects compiled from .c files +user-cobjs := $(sort $(foreach m, $(userprogs), $($(m)-objs))) + +user-csingle := $(addprefix $(obj)/, $(user-csingle)) +user-cmulti := $(addprefix $(obj)/, $(user-cmulti)) +user-cobjs := $(addprefix $(obj)/, $(user-cobjs)) + +user_ccflags = -Wp,-MMD,$(depfile) $(KBUILD_USERCFLAGS) $(userccflags) \ + $($(target-stem)-userccflags) +user_ldflags = $(KBUILD_USERLDFLAGS) $(userldflags) $($(target-stem)-userldflags) +user_ldlibs = $(userldlibs) $($(target-stem)-userldlibs) + +# Create an executable from a single .c file +quiet_cmd_user_cc_c = CC [U] $@ + cmd_user_cc_c = $(CC) $(user_ccflags) $(user_ldflags) -o $@ $< \ + $(user_ldlibs) +$(user-csingle): $(obj)/%: $(src)/%.c FORCE + $(call if_changed_dep,user_cc_c) + +# Link an executable based on list of .o files +quiet_cmd_user_ld = LD [U] $@ + cmd_user_ld = $(CC) $(user_ldflags) -o $@ \ + $(addprefix $(obj)/, $($(target-stem)-objs)) $(user_ldlibs) +$(user-cmulti): FORCE + $(call if_changed,user_ld) +$(call multi_depend, $(user-cmulti), , -objs) + +# Create .o file from a .c file +quiet_cmd_user_cc_o_c = CC [U] $@ + cmd_user_cc_o_c = $(CC) $(user_ccflags) -c -o $@ $< +$(user-cobjs): $(obj)/%.o: $(src)/%.c FORCE + $(call if_changed_dep,user_cc_o_c) + +targets += $(user-csingle) $(user-cmulti) $(user-cobjs) -- cgit v1.3.1