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/sni/reset.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 arch/mips/sni/reset.c (limited to 'arch/mips/sni/reset.c') diff --git a/arch/mips/sni/reset.c b/arch/mips/sni/reset.c new file mode 100644 index 000000000..66f963d8d --- /dev/null +++ b/arch/mips/sni/reset.c @@ -0,0 +1,48 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/arch/mips/sni/process.c + * + * Reset a SNI machine. + */ +#include + +#include +#include +#include + +/* + * This routine reboots the machine by asking the keyboard + * controller to pulse the reset-line low. We try that for a while, + * and if it doesn't work, we do some other stupid things. + */ +static inline void kb_wait(void) +{ + int i; + + for (i = 0; i < 0x10000; i++) + if ((inb_p(0x64) & 0x02) == 0) + break; +} + +/* XXX This ends up at the ARC firmware prompt ... */ +void sni_machine_restart(char *command) +{ + int i; + + /* This does a normal via the keyboard controller like a PC. + We can do that easier ... */ + local_irq_disable(); + for (;;) { + for (i = 0; i < 100; i++) { + kb_wait(); + udelay(50); + outb_p(0xfe, 0x64); /* pulse reset low */ + udelay(50); + } + } +} + +void sni_machine_power_off(void) +{ + *(volatile unsigned char *)PCIMT_CSWCSM = 0xfd; +} -- cgit v1.3.1