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, 27 insertions, 0 deletions

diff --git a/drivers/parisc/README.dino b/drivers/parisc/README.dino
new file mode 100644
index 000000000..162742699
--- /dev/null
+++ b/drivers/parisc/README.dino
@@ -0,0 +1,27 @@
+/*
+** HP VISUALIZE Workstation PCI Bus Defect
+**
+** "HP has discovered a potential system defect that can affect
+** the behavior of five models of HP VISUALIZE workstations when
+** equipped with third-party or customer-installed PCI I/O expansion
+** cards. The defect is limited to the HP C180, C160, C160L, B160L,
+** and B132L VISUALIZE workstations, and will only be encountered
+** when data is transmitted through PCI I/O expansion cards on the
+** PCI bus. HP-supplied graphics cards that utilize the PCI bus are
+** not affected."
+**
+** http://h20000.www2.hp.com/bizsupport/TechSupport/Home.jsp?locale=en_US&prodTypeId=12454&prodSeriesId=44443
+**
+**	Product		First Good Serial Number
+**  C200/C240 (US)	US67350000
+**B132L+/B180 (US)	US67390000
+**   C200 (Europe)	3713G01000
+**  B180L (Europe)	3720G01000
+**
+** Note that many boards were fixed/replaced under a free replacement
+** program. Assume a machine is only "suspect" until proven otherwise.
+**
+** "The pci_check program will also be available as application
+**  patch PHSS_12295"
+*/
+