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/mips/sgi-ip30/ip30-console.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 arch/mips/sgi-ip30/ip30-console.c (limited to 'arch/mips/sgi-ip30/ip30-console.c') diff --git a/arch/mips/sgi-ip30/ip30-console.c b/arch/mips/sgi-ip30/ip30-console.c new file mode 100644 index 000000000..a5f10097b --- /dev/null +++ b/arch/mips/sgi-ip30/ip30-console.c @@ -0,0 +1,25 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include + +#include +#include + +static inline struct ioc3_uartregs *console_uart(void) +{ + struct ioc3 *ioc3; + + ioc3 = (struct ioc3 *)((void *)(0x900000001f600000)); + return &ioc3->sregs.uarta; +} + +void prom_putchar(char c) +{ + struct ioc3_uartregs *uart = console_uart(); + + while ((readb(&uart->iu_lsr) & 0x20) == 0) + cpu_relax(); + + writeb(c, &uart->iu_thr); +} -- cgit v1.3.1