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/m68k/coldfire/cache.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 arch/m68k/coldfire/cache.c (limited to 'arch/m68k/coldfire/cache.c') diff --git a/arch/m68k/coldfire/cache.c b/arch/m68k/coldfire/cache.c new file mode 100644 index 000000000..98ee89b87 --- /dev/null +++ b/arch/m68k/coldfire/cache.c @@ -0,0 +1,49 @@ +// SPDX-License-Identifier: GPL-2.0 +/***************************************************************************/ + +/* + * cache.c -- general ColdFire Cache maintenance code + * + * Copyright (C) 2010, Greg Ungerer (gerg@snapgear.com) + */ + +/***************************************************************************/ + +#include +#include +#include + +/***************************************************************************/ +#ifdef CACHE_PUSH +/***************************************************************************/ + +/* + * Use cpushl to push all dirty cache lines back to memory. + * Older versions of GAS don't seem to know how to generate the + * ColdFire cpushl instruction... Oh well, bit stuff it for now. + */ + +void mcf_cache_push(void) +{ + __asm__ __volatile__ ( + "clrl %%d0\n\t" + "1:\n\t" + "movel %%d0,%%a0\n\t" + "2:\n\t" + ".word 0xf468\n\t" + "addl %0,%%a0\n\t" + "cmpl %1,%%a0\n\t" + "blt 2b\n\t" + "addql #1,%%d0\n\t" + "cmpil %2,%%d0\n\t" + "bne 1b\n\t" + : /* No output */ + : "i" (CACHE_LINE_SIZE), + "i" (DCACHE_SIZE / CACHE_WAYS), + "i" (CACHE_WAYS) + : "d0", "a0" ); +} + +/***************************************************************************/ +#endif /* CACHE_PUSH */ +/***************************************************************************/ -- cgit v1.3.1