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, 73 insertions, 0 deletions

diff --git a/drivers/scsi/sd_dif.c b/drivers/scsi/sd_dif.c
new file mode 100644
index 000000000..ff4217fef
--- /dev/null
+++ b/drivers/scsi/sd_dif.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * sd_dif.c - SCSI Data Integrity Field
+ *
+ * Copyright (C) 2007, 2008 Oracle Corporation
+ * Written by: Martin K. Petersen <martin.petersen@oracle.com>
+ */
+
+#include <linux/blk-integrity.h>
+#include <linux/t10-pi.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_dbg.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_driver.h>
+#include <scsi/scsi_eh.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_ioctl.h>
+#include <scsi/scsicam.h>
+
+#include "sd.h"
+
+/*
+ * Configure exchange of protection information between OS and HBA.
+ */
+void sd_dif_config_host(struct scsi_disk *sdkp, struct queue_limits *lim)
+{
+	struct scsi_device *sdp = sdkp->device;
+	u8 type = sdkp->protection_type;
+	struct blk_integrity *bi = &lim->integrity;
+	int dif, dix;
+
+	memset(bi, 0, sizeof(*bi));
+
+	dif = scsi_host_dif_capable(sdp->host, type);
+	dix = scsi_host_dix_capable(sdp->host, type);
+
+	if (!dix && scsi_host_dix_capable(sdp->host, 0)) {
+		dif = 0; dix = 1;
+	}
+
+	if (!dix)
+		return;
+
+	/* Enable DMA of protection information */
+	if (scsi_host_get_guard(sdkp->device->host) & SHOST_DIX_GUARD_IP)
+		bi->csum_type = BLK_INTEGRITY_CSUM_IP;
+	else
+		bi->csum_type = BLK_INTEGRITY_CSUM_CRC;
+
+	if (type != T10_PI_TYPE3_PROTECTION)
+		bi->flags |= BLK_INTEGRITY_REF_TAG;
+
+	bi->metadata_size = sizeof(struct t10_pi_tuple);
+	bi->pi_tuple_size = bi->metadata_size;
+
+	if (dif && type) {
+		bi->flags |= BLK_INTEGRITY_DEVICE_CAPABLE;
+
+		if (!sdkp->ATO)
+			return;
+
+		if (type == T10_PI_TYPE3_PROTECTION)
+			bi->tag_size = sizeof(u16) + sizeof(u32);
+		else
+			bi->tag_size = sizeof(u16);
+	}
+
+	sd_first_printk(KERN_NOTICE, sdkp,
+			"Enabling DIX %s, application tag size %u bytes\n",
+			blk_integrity_profile_name(bi), bi->tag_size);
+}