ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.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 */