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 --- arch/x86/boot/mtools.conf.in | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) create mode 100644 arch/x86/boot/mtools.conf.in (limited to 'arch/x86/boot/mtools.conf.in') diff --git a/arch/x86/boot/mtools.conf.in b/arch/x86/boot/mtools.conf.in new file mode 100644 index 000000000..174c60508 --- /dev/null +++ b/arch/x86/boot/mtools.conf.in @@ -0,0 +1,21 @@ +# +# mtools configuration file for "make (b)zdisk" +# + +# Actual floppy drive +drive a: + file="/dev/fd0" + +# 1.44 MB floppy disk image +drive v: + file="@OBJ@/fdimage" cylinders=80 heads=2 sectors=18 filter + +# 2.88 MB floppy disk image (mostly for virtual uses) +drive w: + file="@OBJ@/fdimage" cylinders=80 heads=2 sectors=36 filter + +# Hard disk (h: for the filesystem, p: for format - old mtools bug?) +drive h: + file="@OBJ@/hdimage" offset=32768 mformat_only +drive p: + file="@OBJ@/hdimage" partition=1 mformat_only -- cgit v1.3.1