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/pci/ops-mace.c | 100 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 100 insertions(+) create mode 100644 arch/mips/pci/ops-mace.c (limited to 'arch/mips/pci/ops-mace.c') diff --git a/arch/mips/pci/ops-mace.c b/arch/mips/pci/ops-mace.c new file mode 100644 index 000000000..951d8070f --- /dev/null +++ b/arch/mips/pci/ops-mace.c @@ -0,0 +1,100 @@ +/* + * 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. + * + * Copyright (C) 2000, 2001 Keith M Wesolowski + */ +#include +#include +#include +#include + +#if 0 +# define DPRINTK(args...) printk(args); +#else +# define DPRINTK(args...) +#endif + +/* + * O2 has up to 5 PCI devices connected into the MACE bridge. The device + * map looks like this: + * + * 0 aic7xxx 0 + * 1 aic7xxx 1 + * 2 expansion slot + * 3 N/C + * 4 N/C + */ + +static inline int mkaddr(struct pci_bus *bus, unsigned int devfn, + unsigned int reg) +{ + return ((bus->number & 0xff) << 16) | + ((devfn & 0xff) << 8) | + (reg & 0xfc); +} + + +static int +mace_pci_read_config(struct pci_bus *bus, unsigned int devfn, + int reg, int size, u32 *val) +{ + u32 control = mace->pci.control; + + /* disable master aborts interrupts during config read */ + mace->pci.control = control & ~MACEPCI_CONTROL_MAR_INT; + mace->pci.config_addr = mkaddr(bus, devfn, reg); + switch (size) { + case 1: + *val = mace->pci.config_data.b[(reg & 3) ^ 3]; + break; + case 2: + *val = mace->pci.config_data.w[((reg >> 1) & 1) ^ 1]; + break; + case 4: + *val = mace->pci.config_data.l; + break; + } + /* ack possible master abort */ + mace->pci.error &= ~MACEPCI_ERROR_MASTER_ABORT; + mace->pci.control = control; + /* + * someone forgot to set the ultra bit for the onboard + * scsi chips; we fake it here + */ + if (bus->number == 0 && reg == 0x40 && size == 4 && + (devfn == (1 << 3) || devfn == (2 << 3))) + *val |= 0x1000; + + DPRINTK("read%d: reg=%08x,val=%02x\n", size * 8, reg, *val); + + return PCIBIOS_SUCCESSFUL; +} + +static int +mace_pci_write_config(struct pci_bus *bus, unsigned int devfn, + int reg, int size, u32 val) +{ + mace->pci.config_addr = mkaddr(bus, devfn, reg); + switch (size) { + case 1: + mace->pci.config_data.b[(reg & 3) ^ 3] = val; + break; + case 2: + mace->pci.config_data.w[((reg >> 1) & 1) ^ 1] = val; + break; + case 4: + mace->pci.config_data.l = val; + break; + } + + DPRINTK("write%d: reg=%08x,val=%02x\n", size * 8, reg, val); + + return PCIBIOS_SUCCESSFUL; +} + +struct pci_ops mace_pci_ops = { + .read = mace_pci_read_config, + .write = mace_pci_write_config, +}; -- cgit v1.3.1