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/microwatt.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) create mode 100644 arch/powerpc/boot/microwatt.c (limited to 'arch/powerpc/boot/microwatt.c') diff --git a/arch/powerpc/boot/microwatt.c b/arch/powerpc/boot/microwatt.c new file mode 100644 index 000000000..ca9d83617 --- /dev/null +++ b/arch/powerpc/boot/microwatt.c @@ -0,0 +1,24 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#include +#include "stdio.h" +#include "types.h" +#include "io.h" +#include "ops.h" + +BSS_STACK(8192); + +void platform_init(unsigned long r3, unsigned long r4, unsigned long r5) +{ + unsigned long heapsize = 16*1024*1024 - (unsigned long)_end; + + /* + * Disable interrupts and turn off MSR_RI, since we'll + * shortly be overwriting the interrupt vectors. + */ + __asm__ volatile("mtmsrd %0,1" : : "r" (0)); + + simple_alloc_init(_end, heapsize, 32, 64); + fdt_init(_dtb_start); + serial_console_init(); +} -- cgit v1.3.1