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/lib/memmove.c | 121 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 121 insertions(+) create mode 100644 arch/m68k/lib/memmove.c (limited to 'arch/m68k/lib/memmove.c') diff --git a/arch/m68k/lib/memmove.c b/arch/m68k/lib/memmove.c new file mode 100644 index 000000000..e33f00b02 --- /dev/null +++ b/arch/m68k/lib/memmove.c @@ -0,0 +1,121 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file COPYING in the main directory of this archive + * for more details. + */ + +#include +#include + +void *memmove(void *dest, const void *src, size_t n) +{ + void *xdest = dest; + size_t temp; + + if (!n) + return xdest; + + if (dest < src) { + if ((long)dest & 1) { + char *cdest = dest; + const char *csrc = src; + *cdest++ = *csrc++; + dest = cdest; + src = csrc; + n--; + } +#if defined(CONFIG_M68000) + if ((long)src & 1) { + char *cdest = dest; + const char *csrc = src; + for (; n; n--) + *cdest++ = *csrc++; + return xdest; + } +#endif + if (n > 2 && (long)dest & 2) { + short *sdest = dest; + const short *ssrc = src; + *sdest++ = *ssrc++; + dest = sdest; + src = ssrc; + n -= 2; + } + temp = n >> 2; + if (temp) { + long *ldest = dest; + const long *lsrc = src; + temp--; + do + *ldest++ = *lsrc++; + while (temp--); + dest = ldest; + src = lsrc; + } + if (n & 2) { + short *sdest = dest; + const short *ssrc = src; + *sdest++ = *ssrc++; + dest = sdest; + src = ssrc; + } + if (n & 1) { + char *cdest = dest; + const char *csrc = src; + *cdest = *csrc; + } + } else { + dest = (char *)dest + n; + src = (const char *)src + n; + if ((long)dest & 1) { + char *cdest = dest; + const char *csrc = src; + *--cdest = *--csrc; + dest = cdest; + src = csrc; + n--; + } +#if defined(CONFIG_M68000) + if ((long)src & 1) { + char *cdest = dest; + const char *csrc = src; + for (; n; n--) + *--cdest = *--csrc; + return xdest; + } +#endif + if (n > 2 && (long)dest & 2) { + short *sdest = dest; + const short *ssrc = src; + *--sdest = *--ssrc; + dest = sdest; + src = ssrc; + n -= 2; + } + temp = n >> 2; + if (temp) { + long *ldest = dest; + const long *lsrc = src; + temp--; + do + *--ldest = *--lsrc; + while (temp--); + dest = ldest; + src = lsrc; + } + if (n & 2) { + short *sdest = dest; + const short *ssrc = src; + *--sdest = *--ssrc; + dest = sdest; + src = ssrc; + } + if (n & 1) { + char *cdest = dest; + const char *csrc = src; + *--cdest = *--csrc; + } + } + return xdest; +} +EXPORT_SYMBOL(memmove); -- cgit v1.3.1