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, 92 insertions, 0 deletions

diff --git a/drivers/video/backlight/ltv350qv.h b/drivers/video/backlight/ltv350qv.h
new file mode 100644
index 000000000..c70890776
--- /dev/null
+++ b/drivers/video/backlight/ltv350qv.h
@@ -0,0 +1,92 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Register definitions for Samsung LTV350QV Quarter VGA LCD Panel
+ *
+ * Copyright (C) 2006, 2007 Atmel Corporation
+ */
+#ifndef __LTV350QV_H
+#define __LTV350QV_H
+
+#define LTV_OPC_INDEX	0x74
+#define LTV_OPC_DATA	0x76
+
+#define LTV_ID		0x00		/* ID Read */
+#define LTV_IFCTL	0x01		/* Display Interface Control */
+#define LTV_DATACTL	0x02		/* Display Data Control */
+#define LTV_ENTRY_MODE	0x03		/* Entry Mode */
+#define LTV_GATECTL1	0x04		/* Gate Control 1 */
+#define LTV_GATECTL2	0x05		/* Gate Control 2 */
+#define LTV_VBP		0x06		/* Vertical Back Porch */
+#define LTV_HBP		0x07		/* Horizontal Back Porch */
+#define LTV_SOTCTL	0x08		/* Source Output Timing Control */
+#define LTV_PWRCTL1	0x09		/* Power Control 1 */
+#define LTV_PWRCTL2	0x0a		/* Power Control 2 */
+#define LTV_GAMMA(x)	(0x10 + (x))	/* Gamma control */
+
+/* Bit definitions for LTV_IFCTL */
+#define LTV_IM			(1 << 15)
+#define LTV_NMD			(1 << 14)
+#define LTV_SSMD		(1 << 13)
+#define LTV_REV			(1 <<  7)
+#define LTV_NL(x)		(((x) & 0x001f) << 0)
+
+/* Bit definitions for LTV_DATACTL */
+#define LTV_DS_SAME		(0 << 12)
+#define LTV_DS_D_TO_S		(1 << 12)
+#define LTV_DS_S_TO_D		(2 << 12)
+#define LTV_CHS_384		(0 <<  9)
+#define LTV_CHS_480		(1 <<  9)
+#define LTV_CHS_492		(2 <<  9)
+#define LTV_DF_RGB		(0 <<  6)
+#define LTV_DF_RGBX		(1 <<  6)
+#define LTV_DF_XRGB		(2 <<  6)
+#define LTV_RGB_RGB		(0 <<  2)
+#define LTV_RGB_BGR		(1 <<  2)
+#define LTV_RGB_GRB		(2 <<  2)
+#define LTV_RGB_RBG		(3 <<  2)
+
+/* Bit definitions for LTV_ENTRY_MODE */
+#define LTV_VSPL_ACTIVE_LOW	(0 << 15)
+#define LTV_VSPL_ACTIVE_HIGH	(1 << 15)
+#define LTV_HSPL_ACTIVE_LOW	(0 << 14)
+#define LTV_HSPL_ACTIVE_HIGH	(1 << 14)
+#define LTV_DPL_SAMPLE_RISING	(0 << 13)
+#define LTV_DPL_SAMPLE_FALLING	(1 << 13)
+#define LTV_EPL_ACTIVE_LOW	(0 << 12)
+#define LTV_EPL_ACTIVE_HIGH	(1 << 12)
+#define LTV_SS_LEFT_TO_RIGHT	(0 <<  8)
+#define LTV_SS_RIGHT_TO_LEFT	(1 <<  8)
+#define LTV_STB			(1 <<  1)
+
+/* Bit definitions for LTV_GATECTL1 */
+#define LTV_CLW(x)		(((x) & 0x0007) << 12)
+#define LTV_GAON		(1 <<  5)
+#define LTV_SDR			(1 <<  3)
+
+/* Bit definitions for LTV_GATECTL2 */
+#define LTV_NW_INV_FRAME	(0 << 14)
+#define LTV_NW_INV_1LINE	(1 << 14)
+#define LTV_NW_INV_2LINE	(2 << 14)
+#define LTV_DSC			(1 << 12)
+#define LTV_GIF			(1 <<  8)
+#define LTV_FHN			(1 <<  7)
+#define LTV_FTI(x)		(((x) & 0x0003) << 4)
+#define LTV_FWI(x)		(((x) & 0x0003) << 0)
+
+/* Bit definitions for LTV_SOTCTL */
+#define LTV_SDT(x)		(((x) & 0x0007) << 10)
+#define LTV_EQ(x)		(((x) & 0x0007) <<  2)
+
+/* Bit definitions for LTV_PWRCTL1 */
+#define LTV_VCOM_DISABLE	(1 << 14)
+#define LTV_VCOMOUT_ENABLE	(1 << 11)
+#define LTV_POWER_ON		(1 <<  9)
+#define LTV_DRIVE_CURRENT(x)	(((x) & 0x0007) << 4)	/* 0=off, 5=max */
+#define LTV_SUPPLY_CURRENT(x)	(((x) & 0x0007) << 0)	/* 0=off, 5=max */
+
+/* Bit definitions for LTV_PWRCTL2 */
+#define LTV_VCOML_ENABLE	(1 << 13)
+#define LTV_VCOML_VOLTAGE(x)	(((x) & 0x001f) << 8)	/* 0=1V, 31=-1V */
+#define LTV_VCOMH_VOLTAGE(x)	(((x) & 0x001f) << 0)	/* 0=3V, 31=4.5V */
+
+#endif /* __LTV350QV_H */