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, 52 insertions, 0 deletions

diff --git a/drivers/target/Kconfig b/drivers/target/Kconfig
new file mode 100644
index 000000000..92641d391
--- /dev/null
+++ b/drivers/target/Kconfig
@@ -0,0 +1,52 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+menuconfig TARGET_CORE
+	tristate "Generic Target Core Mod (TCM) and ConfigFS Infrastructure"
+	depends on BLOCK
+	select CONFIGFS_FS
+	select CRC_T10DIF
+	select SCSI_COMMON
+	select SGL_ALLOC
+	default n
+	help
+	Say Y or M here to enable the TCM Storage Engine and ConfigFS enabled
+	control path for target_core_mod.  This includes built-in TCM RAMDISK
+	subsystem logic for virtual LUN 0 access
+
+if TARGET_CORE
+
+config TCM_IBLOCK
+	tristate "TCM/IBLOCK Subsystem Plugin for Linux/BLOCK"
+	select BLK_DEV_INTEGRITY
+	help
+	Say Y here to enable the TCM/IBLOCK subsystem plugin for non-buffered
+	access to Linux/Block devices using BIO
+
+config TCM_FILEIO
+	tristate "TCM/FILEIO Subsystem Plugin for Linux/VFS"
+	help
+	Say Y here to enable the TCM/FILEIO subsystem plugin for buffered
+	access to Linux/VFS struct file or struct block_device
+
+config TCM_PSCSI
+	tristate "TCM/pSCSI Subsystem Plugin for Linux/SCSI"
+	depends on SCSI
+	help
+	Say Y here to enable the TCM/pSCSI subsystem plugin for non-buffered
+	passthrough access to Linux/SCSI device
+
+config TCM_USER2
+	tristate "TCM/USER Subsystem Plugin for Linux"
+	depends on UIO && NET
+	help
+	Say Y here to enable the TCM/USER subsystem plugin for a userspace
+	process to handle requests. This is version 2 of the ABI; version 1
+	is obsolete.
+
+source "drivers/target/loopback/Kconfig"
+source "drivers/target/tcm_fc/Kconfig"
+source "drivers/target/iscsi/Kconfig"
+source "drivers/target/sbp/Kconfig"
+source "drivers/target/tcm_remote/Kconfig"
+
+endif