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, 259 insertions, 0 deletions

diff --git a/drivers/scsi/nsp32_io.h b/drivers/scsi/nsp32_io.h
new file mode 100644
index 000000000..e3f3c27b0
--- /dev/null
+++ b/drivers/scsi/nsp32_io.h
@@ -0,0 +1,259 @@
+/*
+ * Workbit NinjaSCSI-32Bi/UDE PCI/CardBus SCSI Host Bus Adapter driver
+ * I/O routine
+ *
+ * This software may be used and distributed according to the terms of
+ * the GNU General Public License.
+ */
+
+#ifndef _NSP32_IO_H
+#define _NSP32_IO_H
+
+static inline void nsp32_write1(unsigned int  base,
+				unsigned int  index,
+				unsigned char val)
+{
+	outb(val, (base + index));
+}
+
+static inline unsigned char nsp32_read1(unsigned int base,
+					unsigned int index)
+{
+	return inb(base + index);
+}
+
+static inline void nsp32_write2(unsigned int   base,
+				unsigned int   index,
+				unsigned short val)
+{
+	outw(val, (base + index));
+}
+
+static inline unsigned short nsp32_read2(unsigned int base,
+					 unsigned int index)
+{
+	return inw(base + index);
+}
+
+static inline void nsp32_write4(unsigned int  base,
+				unsigned int  index,
+				unsigned long val)
+{
+	outl(val, (base + index));
+}
+
+static inline unsigned long nsp32_read4(unsigned int base,
+					unsigned int index)
+{
+	return inl(base + index);
+}
+
+/*==============================================*/
+
+static inline void nsp32_mmio_write1(unsigned long base,
+				     unsigned int  index,
+				     unsigned char val)
+{
+	volatile unsigned char *ptr;
+
+	ptr = (unsigned char *)(base + NSP32_MMIO_OFFSET + index);
+
+	writeb(val, ptr);
+}
+
+static inline unsigned char nsp32_mmio_read1(unsigned long base,
+					     unsigned int  index)
+{
+	volatile unsigned char *ptr;
+
+	ptr = (unsigned char *)(base + NSP32_MMIO_OFFSET + index);
+
+	return readb(ptr);
+}
+
+static inline void nsp32_mmio_write2(unsigned long  base,
+				     unsigned int   index,
+				     unsigned short val)
+{
+	volatile unsigned short *ptr;
+
+	ptr = (unsigned short *)(base + NSP32_MMIO_OFFSET + index);
+
+	writew(cpu_to_le16(val), ptr);
+}
+
+static inline unsigned short nsp32_mmio_read2(unsigned long base,
+					      unsigned int  index)
+{
+	volatile unsigned short *ptr;
+
+	ptr = (unsigned short *)(base + NSP32_MMIO_OFFSET + index);
+
+	return le16_to_cpu(readw(ptr));
+}
+
+static inline void nsp32_mmio_write4(unsigned long base,
+				     unsigned int  index,
+				     unsigned long val)
+{
+	volatile unsigned long *ptr;
+
+	ptr = (unsigned long *)(base + NSP32_MMIO_OFFSET + index);
+
+	writel(cpu_to_le32(val), ptr);
+}
+
+static inline unsigned long nsp32_mmio_read4(unsigned long base,
+					     unsigned int  index)
+{
+	volatile unsigned long *ptr;
+
+	ptr = (unsigned long *)(base + NSP32_MMIO_OFFSET + index);
+
+	return le32_to_cpu(readl(ptr));
+}
+
+/*==============================================*/
+
+static inline unsigned char nsp32_index_read1(unsigned int base,
+					      unsigned int reg)
+{
+	outb(reg, base + INDEX_REG);
+	return inb(base + DATA_REG_LOW);
+}
+
+static inline void nsp32_index_write1(unsigned int  base,
+				      unsigned int  reg,
+				      unsigned char val)
+{
+	outb(reg, base + INDEX_REG   );
+	outb(val, base + DATA_REG_LOW);
+}
+
+static inline unsigned short nsp32_index_read2(unsigned int base,
+					       unsigned int reg)
+{
+	outb(reg, base + INDEX_REG);
+	return inw(base + DATA_REG_LOW);
+}
+
+static inline void nsp32_index_write2(unsigned int   base,
+				      unsigned int   reg,
+				      unsigned short val)
+{
+	outb(reg, base + INDEX_REG   );
+	outw(val, base + DATA_REG_LOW);
+}
+
+static inline unsigned long nsp32_index_read4(unsigned int base,
+					      unsigned int reg)
+{
+	unsigned long h,l;
+
+	outb(reg, base + INDEX_REG);
+	l = inw(base + DATA_REG_LOW);
+	h = inw(base + DATA_REG_HI );
+
+	return ((h << 16) | l);
+}
+
+static inline void nsp32_index_write4(unsigned int  base,
+				      unsigned int  reg,
+				      unsigned long val)
+{
+	unsigned long h,l;
+
+	h = (val & 0xffff0000) >> 16;
+	l = (val & 0x0000ffff) >>  0;
+
+	outb(reg, base + INDEX_REG   );
+	outw(l,   base + DATA_REG_LOW);
+	outw(h,   base + DATA_REG_HI );
+}
+
+/*==============================================*/
+
+static inline unsigned char nsp32_mmio_index_read1(unsigned long base,
+						   unsigned int reg)
+{
+	volatile unsigned short *index_ptr, *data_ptr;
+
+	index_ptr = (unsigned short *)(base + NSP32_MMIO_OFFSET + INDEX_REG);
+	data_ptr  = (unsigned short *)(base + NSP32_MMIO_OFFSET + DATA_REG_LOW);
+
+	writeb(reg, index_ptr);
+	return readb(data_ptr);
+}
+
+static inline void nsp32_mmio_index_write1(unsigned long base,
+					   unsigned int  reg,
+					   unsigned char val)
+{
+	volatile unsigned short *index_ptr, *data_ptr;
+
+	index_ptr = (unsigned short *)(base + NSP32_MMIO_OFFSET + INDEX_REG);
+	data_ptr  = (unsigned short *)(base + NSP32_MMIO_OFFSET + DATA_REG_LOW);
+
+	writeb(reg, index_ptr);
+	writeb(val, data_ptr );
+}
+
+static inline unsigned short nsp32_mmio_index_read2(unsigned long base,
+						    unsigned int  reg)
+{
+	volatile unsigned short *index_ptr, *data_ptr;
+
+	index_ptr = (unsigned short *)(base + NSP32_MMIO_OFFSET + INDEX_REG);
+	data_ptr  = (unsigned short *)(base + NSP32_MMIO_OFFSET + DATA_REG_LOW);
+
+	writeb(reg, index_ptr);
+	return le16_to_cpu(readw(data_ptr));
+}
+
+static inline void nsp32_mmio_index_write2(unsigned long  base,
+					   unsigned int   reg,
+					   unsigned short val)
+{
+	volatile unsigned short *index_ptr, *data_ptr;
+
+	index_ptr = (unsigned short *)(base + NSP32_MMIO_OFFSET + INDEX_REG);
+	data_ptr  = (unsigned short *)(base + NSP32_MMIO_OFFSET + DATA_REG_LOW);
+
+	writeb(reg,              index_ptr);
+	writew(cpu_to_le16(val), data_ptr );
+}
+
+/*==============================================*/
+
+static inline void nsp32_multi_read4(unsigned int   base,
+				     unsigned int   reg,
+				     void          *buf,
+				     unsigned long  count)
+{
+	insl(base + reg, buf, count);
+}
+
+static inline void nsp32_fifo_read(unsigned int   base,
+				   void          *buf,
+				   unsigned long  count)
+{
+	nsp32_multi_read4(base, FIFO_DATA_LOW, buf, count);
+}
+
+static inline void nsp32_multi_write4(unsigned int   base,
+				      unsigned int   reg,
+				      void          *buf,
+				      unsigned long  count)
+{
+	outsl(base + reg, buf, count);
+}
+
+static inline void nsp32_fifo_write(unsigned int   base,
+				    void          *buf,
+				    unsigned long  count)
+{
+	nsp32_multi_write4(base, FIFO_DATA_LOW, buf, count);
+}
+
+#endif /* _NSP32_IO_H */
+/* end */