selftests/bpf: Reject graph kptr use after RCU unlockgrafted

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 <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 77 insertions, 0 deletions

diff --git a/arch/mips/sgi-ip22/ip22-setup.c b/arch/mips/sgi-ip22/ip22-setup.c
new file mode 100644
index 000000000..f083b25be
--- /dev/null
+++ b/arch/mips/sgi-ip22/ip22-setup.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ip22-setup.c: SGI specific setup, including init of the feature struct.
+ *
+ * Copyright (C) 1996 David S. Miller (davem@davemloft.net)
+ * Copyright (C) 1997, 1998 Ralf Baechle (ralf@gnu.org)
+ */
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/kdev_t.h>
+#include <linux/types.h>
+#include <linux/console.h>
+#include <linux/sched.h>
+#include <linux/string.h>
+#include <linux/tty.h>
+
+#include <asm/addrspace.h>
+#include <asm/bcache.h>
+#include <asm/bootinfo.h>
+#include <asm/irq.h>
+#include <asm/reboot.h>
+#include <asm/time.h>
+#include <asm/io.h>
+#include <asm/traps.h>
+#include <asm/sgialib.h>
+#include <asm/sgi/mc.h>
+#include <asm/sgi/hpc3.h>
+#include <asm/sgi/ip22.h>
+
+void __init plat_mem_setup(void)
+{
+	char *ctype;
+	char *cserial;
+
+	board_be_init = ip22_be_init;
+
+	/* Init the INDY HPC I/O controller.  Need to call this before
+	 * fucking with the memory controller because it needs to know the
+	 * boardID and whether this is a Guiness or a FullHouse machine.
+	 */
+	sgihpc_init();
+
+	/* Init INDY memory controller. */
+	sgimc_init();
+
+#ifdef CONFIG_BOARD_SCACHE
+	/* Now enable boardcaches, if any. */
+	indy_sc_init();
+#endif
+
+	/* Set EISA IO port base for Indigo2
+	 * ioremap cannot fail */
+	set_io_port_base((unsigned long)ioremap(0x00080000,
+						0x1fffffff - 0x00080000));
+	/* ARCS console environment variable is set to "g?" for
+	 * graphics console, it is set to "d" for the first serial
+	 * line and "d2" for the second serial line.
+	 *
+	 * Need to check if the case is 'g' but no keyboard:
+	 * (ConsoleIn/Out = serial)
+	 */
+	ctype = ArcGetEnvironmentVariable("console");
+	cserial = ArcGetEnvironmentVariable("ConsoleOut");
+
+	if ((ctype && *ctype == 'd') || (cserial && *cserial == 's')) {
+		static char options[8] __initdata;
+		char *baud = ArcGetEnvironmentVariable("dbaud");
+		if (baud)
+			strscpy(options, baud);
+		add_preferred_console("ttyS", *(ctype + 1) == '2' ? 1 : 0,
+				      baud ? options : NULL);
+	} else if (!ctype || *ctype != 'g') {
+		/* Use ARC if we don't want serial ('d') or graphics ('g'). */
+		prom_flags |= PROM_FLAG_USE_AS_CONSOLE;
+		add_preferred_console("arc", 0, NULL);
+	}
+}