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/alpha/boot/bootloader.lds | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 arch/alpha/boot/bootloader.lds (limited to 'arch/alpha/boot/bootloader.lds') diff --git a/arch/alpha/boot/bootloader.lds b/arch/alpha/boot/bootloader.lds new file mode 100644 index 000000000..8cdff54c6 --- /dev/null +++ b/arch/alpha/boot/bootloader.lds @@ -0,0 +1,25 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +OUTPUT_FORMAT("elf64-alpha") +ENTRY(__start) +printk = srm_printk; +SECTIONS +{ + . = 0x20000000; + .text : { *(.text) } + _etext = .; + PROVIDE (etext = .); + .rodata : { *(.rodata) *(.rodata.*) } + .data : { *(.data) CONSTRUCTORS } + .got : { *(.got) } + .sdata : { *(.sdata) } + _edata = .; + PROVIDE (edata = .); + .sbss : { *(.sbss) *(.scommon) } + .bss : { *(.bss) *(COMMON) } + _end = . ; + PROVIDE (end = .); + + .mdebug 0 : { *(.mdebug) } + .note 0 : { *(.note) } + .comment 0 : { *(.comment) } +} -- cgit v1.3.1