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/powerpc/boot/zImage.coff.lds.S | 50 +++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 arch/powerpc/boot/zImage.coff.lds.S (limited to 'arch/powerpc/boot/zImage.coff.lds.S') diff --git a/arch/powerpc/boot/zImage.coff.lds.S b/arch/powerpc/boot/zImage.coff.lds.S new file mode 100644 index 000000000..117951295 --- /dev/null +++ b/arch/powerpc/boot/zImage.coff.lds.S @@ -0,0 +1,50 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +OUTPUT_ARCH(powerpc:common) +ENTRY(_zimage_start_opd) +EXTERN(_zimage_start_opd) +SECTIONS +{ + .text : + { + _start = .; + *(.text) + *(.fixup) + _etext = .; + } + . = ALIGN(4096); + .data : + { + *(.rodata*) + *(.data*) + *(__builtin_*) + *(.sdata*) + *(.got2) + + _dtb_start = .; + *(.kernel:dtb) + _dtb_end = .; + + _vmlinux_start = .; + *(.kernel:vmlinux.strip) + _vmlinux_end = .; + + _initrd_start = .; + *(.kernel:initrd) + _initrd_end = .; + } + + . = ALIGN(4096); + _edata = .; + __bss_start = .; + .bss : + { + *(.sbss) + *(.bss) + } + _end = . ; + + /DISCARD/ : + { + *(.comment) + } +} -- cgit v1.3.1