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, 85 insertions, 0 deletions

diff --git a/drivers/scsi/scsi_logging.h b/drivers/scsi/scsi_logging.h
new file mode 100644
index 000000000..3df877886
--- /dev/null
+++ b/drivers/scsi/scsi_logging.h
@@ -0,0 +1,85 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _SCSI_LOGGING_H
+#define _SCSI_LOGGING_H
+
+
+/*
+ * This defines the scsi logging feature.  It is a means by which the user can
+ * select how much information they get about various goings on, and it can be
+ * really useful for fault tracing.  The logging word is divided into 10 3-bit
+ * bitfields, each of which describes a loglevel.  The division of things is
+ * somewhat arbitrary, and the division of the word could be changed if it
+ * were really needed for any reason.  The numbers below are the only place
+ * where these are specified.  For a first go-around, 3 bits is more than
+ * enough, since this gives 8 levels of logging (really 7, since 0 is always
+ * off).  Cutting to 2 bits might be wise at some point.
+ */
+
+#define SCSI_LOG_ERROR_SHIFT              0
+#define SCSI_LOG_TIMEOUT_SHIFT            3
+#define SCSI_LOG_SCAN_SHIFT               6
+#define SCSI_LOG_MLQUEUE_SHIFT            9
+#define SCSI_LOG_MLCOMPLETE_SHIFT         12
+#define SCSI_LOG_LLQUEUE_SHIFT            15
+#define SCSI_LOG_LLCOMPLETE_SHIFT         18
+#define SCSI_LOG_HLQUEUE_SHIFT            21
+#define SCSI_LOG_HLCOMPLETE_SHIFT         24
+#define SCSI_LOG_IOCTL_SHIFT              27
+
+#define SCSI_LOG_ERROR_BITS               3
+#define SCSI_LOG_TIMEOUT_BITS             3
+#define SCSI_LOG_SCAN_BITS                3
+#define SCSI_LOG_MLQUEUE_BITS             3
+#define SCSI_LOG_MLCOMPLETE_BITS          3
+#define SCSI_LOG_LLQUEUE_BITS             3
+#define SCSI_LOG_LLCOMPLETE_BITS          3
+#define SCSI_LOG_HLQUEUE_BITS             3
+#define SCSI_LOG_HLCOMPLETE_BITS          3
+#define SCSI_LOG_IOCTL_BITS               3
+
+extern unsigned int scsi_logging_level;
+
+#ifdef CONFIG_SCSI_LOGGING
+
+#define SCSI_LOG_LEVEL(SHIFT, BITS)				\
+        ((scsi_logging_level >> (SHIFT)) & ((1 << (BITS)) - 1))
+
+#define SCSI_CHECK_LOGGING(SHIFT, BITS, LEVEL, CMD)		\
+do {								\
+        if (unlikely((SCSI_LOG_LEVEL(SHIFT, BITS)) > (LEVEL)))	\
+		do {						\
+			CMD;					\
+		} while (0);					\
+} while (0)
+#else
+#define SCSI_LOG_LEVEL(SHIFT, BITS) 0
+#define SCSI_CHECK_LOGGING(SHIFT, BITS, LEVEL, CMD) do { } while (0)
+#endif /* CONFIG_SCSI_LOGGING */
+
+/*
+ * These are the macros that are actually used throughout the code to
+ * log events.  If logging isn't enabled, they are no-ops and will be
+ * completely absent from the user's code.
+ */
+#define SCSI_LOG_ERROR_RECOVERY(LEVEL,CMD)  \
+        SCSI_CHECK_LOGGING(SCSI_LOG_ERROR_SHIFT, SCSI_LOG_ERROR_BITS, LEVEL,CMD);
+#define SCSI_LOG_TIMEOUT(LEVEL,CMD)  \
+        SCSI_CHECK_LOGGING(SCSI_LOG_TIMEOUT_SHIFT, SCSI_LOG_TIMEOUT_BITS, LEVEL,CMD);
+#define SCSI_LOG_SCAN_BUS(LEVEL,CMD)  \
+        SCSI_CHECK_LOGGING(SCSI_LOG_SCAN_SHIFT, SCSI_LOG_SCAN_BITS, LEVEL,CMD);
+#define SCSI_LOG_MLQUEUE(LEVEL,CMD)  \
+        SCSI_CHECK_LOGGING(SCSI_LOG_MLQUEUE_SHIFT, SCSI_LOG_MLQUEUE_BITS, LEVEL,CMD);
+#define SCSI_LOG_MLCOMPLETE(LEVEL,CMD)  \
+        SCSI_CHECK_LOGGING(SCSI_LOG_MLCOMPLETE_SHIFT, SCSI_LOG_MLCOMPLETE_BITS, LEVEL,CMD);
+#define SCSI_LOG_LLQUEUE(LEVEL,CMD)  \
+        SCSI_CHECK_LOGGING(SCSI_LOG_LLQUEUE_SHIFT, SCSI_LOG_LLQUEUE_BITS, LEVEL,CMD);
+#define SCSI_LOG_LLCOMPLETE(LEVEL,CMD)  \
+        SCSI_CHECK_LOGGING(SCSI_LOG_LLCOMPLETE_SHIFT, SCSI_LOG_LLCOMPLETE_BITS, LEVEL,CMD);
+#define SCSI_LOG_HLQUEUE(LEVEL,CMD)  \
+        SCSI_CHECK_LOGGING(SCSI_LOG_HLQUEUE_SHIFT, SCSI_LOG_HLQUEUE_BITS, LEVEL,CMD);
+#define SCSI_LOG_HLCOMPLETE(LEVEL,CMD)  \
+        SCSI_CHECK_LOGGING(SCSI_LOG_HLCOMPLETE_SHIFT, SCSI_LOG_HLCOMPLETE_BITS, LEVEL,CMD);
+#define SCSI_LOG_IOCTL(LEVEL,CMD)  \
+        SCSI_CHECK_LOGGING(SCSI_LOG_IOCTL_SHIFT, SCSI_LOG_IOCTL_BITS, LEVEL,CMD);
+
+#endif /* _SCSI_LOGGING_H */