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, 256 insertions, 0 deletions

diff --git a/scripts/coccinelle/api/kvmalloc.cocci b/scripts/coccinelle/api/kvmalloc.cocci
new file mode 100644
index 000000000..5ddcb76b7
--- /dev/null
+++ b/scripts/coccinelle/api/kvmalloc.cocci
@@ -0,0 +1,256 @@
+// SPDX-License-Identifier: GPL-2.0-only
+///
+/// Find if/else condition with kmalloc/vmalloc calls.
+/// Suggest to use kvmalloc instead. Same for kvfree.
+///
+// Confidence: High
+// Copyright: (C) 2020 Denis Efremov ISPRAS
+// Options: --no-includes --include-headers
+//
+
+virtual patch
+virtual report
+virtual org
+virtual context
+
+@initialize:python@
+@@
+filter = frozenset(['kvfree'])
+
+def relevant(p):
+    return not (filter & {el.current_element for el in p})
+
+@kvmalloc depends on !patch@
+expression E, E1, size;
+identifier flags;
+binary operator cmp = {<=, <, ==, >, >=};
+identifier x;
+type T;
+position p;
+@@
+
+(
+* if (size cmp E1 || ...)@p {
+    ...
+*    E = \(kmalloc\|kzalloc\|kcalloc\|kmalloc_node\|kzalloc_node\|
+*          kmalloc_array\|kmalloc_array_node\|kcalloc_node\)
+*          (..., size, \(flags\|GFP_KERNEL\|\(GFP_KERNEL\|flags\)|__GFP_NOWARN\), ...)
+    ...
+  } else {
+    ...
+*    E = \(vmalloc\|vzalloc\|vmalloc_node\|vzalloc_node\)(..., size, ...)
+    ...
+  }
+|
+* E = \(kmalloc\|kzalloc\|kcalloc\|kmalloc_node\|kzalloc_node\|
+*       kmalloc_array\|kmalloc_array_node\|kcalloc_node\)
+*       (..., size, \(flags\|GFP_KERNEL\|\(GFP_KERNEL\|flags\)|__GFP_NOWARN\), ...)
+  ... when != E = E1
+      when != size = E1
+      when any
+* if (E == NULL)@p {
+    ...
+*   E = \(vmalloc\|vzalloc\|vmalloc_node\|vzalloc_node\)(..., size, ...)
+    ...
+  }
+|
+* T x = \(kmalloc\|kzalloc\|kcalloc\|kmalloc_node\|kzalloc_node\|
+*         kmalloc_array\|kmalloc_array_node\|kcalloc_node\)
+*         (..., size, \(flags\|GFP_KERNEL\|\(GFP_KERNEL\|flags\)|__GFP_NOWARN\), ...);
+  ... when != x = E1
+      when != size = E1
+      when any
+* if (x == NULL)@p {
+    ...
+*   x = \(vmalloc\|vzalloc\|vmalloc_node\|vzalloc_node\)(..., size, ...)
+    ...
+  }
+)
+
+@kvfree depends on !patch@
+expression E;
+position p : script:python() { relevant(p) };
+@@
+
+* if (is_vmalloc_addr(E))@p {
+    ...
+*   vfree(E)
+    ...
+  } else {
+    ... when != krealloc(E, ...)
+        when any
+*   \(kfree\|kfree_sensitive\)(E)
+    ...
+  }
+
+@depends on patch@
+expression E, E1, size, node;
+binary operator cmp = {<=, <, ==, >, >=};
+identifier flags, x;
+type T;
+@@
+
+(
+- if (size cmp E1)
+-    E = kmalloc(size, flags);
+- else
+-    E = vmalloc(size);
++ E = kvmalloc(size, flags);
+|
+- if (size cmp E1)
+-    E = kmalloc(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\));
+- else
+-    E = vmalloc(size);
++ E = kvmalloc(size, GFP_KERNEL);
+|
+- E = kmalloc(size, flags | __GFP_NOWARN);
+- if (E == NULL)
+-   E = vmalloc(size);
++ E = kvmalloc(size, flags);
+|
+- E = kmalloc(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\));
+- if (E == NULL)
+-   E = vmalloc(size);
++ E = kvmalloc(size, GFP_KERNEL);
+|
+- T x = kmalloc(size, flags | __GFP_NOWARN);
+- if (x == NULL)
+-   x = vmalloc(size);
++ T x = kvmalloc(size, flags);
+|
+- T x = kmalloc(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\));
+- if (x == NULL)
+-   x = vmalloc(size);
++ T x = kvmalloc(size, GFP_KERNEL);
+|
+- if (size cmp E1)
+-    E = kzalloc(size, flags);
+- else
+-    E = vzalloc(size);
++ E = kvzalloc(size, flags);
+|
+- if (size cmp E1)
+-    E = kzalloc(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\));
+- else
+-    E = vzalloc(size);
++ E = kvzalloc(size, GFP_KERNEL);
+|
+- E = kzalloc(size, flags | __GFP_NOWARN);
+- if (E == NULL)
+-   E = vzalloc(size);
++ E = kvzalloc(size, flags);
+|
+- E = kzalloc(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\));
+- if (E == NULL)
+-   E = vzalloc(size);
++ E = kvzalloc(size, GFP_KERNEL);
+|
+- T x = kzalloc(size, flags | __GFP_NOWARN);
+- if (x == NULL)
+-   x = vzalloc(size);
++ T x = kvzalloc(size, flags);
+|
+- T x = kzalloc(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\));
+- if (x == NULL)
+-   x = vzalloc(size);
++ T x = kvzalloc(size, GFP_KERNEL);
+|
+- if (size cmp E1)
+-    E = kmalloc_node(size, flags, node);
+- else
+-    E = vmalloc_node(size, node);
++ E = kvmalloc_node(size, flags, node);
+|
+- if (size cmp E1)
+-    E = kmalloc_node(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\), node);
+- else
+-    E = vmalloc_node(size, node);
++ E = kvmalloc_node(size, GFP_KERNEL, node);
+|
+- E = kmalloc_node(size, flags | __GFP_NOWARN, node);
+- if (E == NULL)
+-   E = vmalloc_node(size, node);
++ E = kvmalloc_node(size, flags, node);
+|
+- E = kmalloc_node(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\), node);
+- if (E == NULL)
+-   E = vmalloc_node(size, node);
++ E = kvmalloc_node(size, GFP_KERNEL, node);
+|
+- T x = kmalloc_node(size, flags | __GFP_NOWARN, node);
+- if (x == NULL)
+-   x = vmalloc_node(size, node);
++ T x = kvmalloc_node(size, flags, node);
+|
+- T x = kmalloc_node(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\), node);
+- if (x == NULL)
+-   x = vmalloc_node(size, node);
++ T x = kvmalloc_node(size, GFP_KERNEL, node);
+|
+- if (size cmp E1)
+-    E = kvzalloc_node(size, flags, node);
+- else
+-    E = vzalloc_node(size, node);
++ E = kvzalloc_node(size, flags, node);
+|
+- if (size cmp E1)
+-    E = kvzalloc_node(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\), node);
+- else
+-    E = vzalloc_node(size, node);
++ E = kvzalloc_node(size, GFP_KERNEL, node);
+|
+- E = kvzalloc_node(size, flags | __GFP_NOWARN, node);
+- if (E == NULL)
+-   E = vzalloc_node(size, node);
++ E = kvzalloc_node(size, flags, node);
+|
+- E = kvzalloc_node(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\), node);
+- if (E == NULL)
+-   E = vzalloc_node(size, node);
++ E = kvzalloc_node(size, GFP_KERNEL, node);
+|
+- T x = kvzalloc_node(size, flags | __GFP_NOWARN, node);
+- if (x == NULL)
+-   x = vzalloc_node(size, node);
++ T x = kvzalloc_node(size, flags, node);
+|
+- T x = kvzalloc_node(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\), node);
+- if (x == NULL)
+-   x = vzalloc_node(size, node);
++ T x = kvzalloc_node(size, GFP_KERNEL, node);
+)
+
+@depends on patch@
+expression E;
+position p : script:python() { relevant(p) };
+@@
+
+- if (is_vmalloc_addr(E))@p
+-   vfree(E);
+- else
+-   kfree(E);
++ kvfree(E);
+
+@script: python depends on report@
+p << kvmalloc.p;
+@@
+
+coccilib.report.print_report(p[0], "WARNING opportunity for kvmalloc")
+
+@script: python depends on org@
+p << kvmalloc.p;
+@@
+
+coccilib.org.print_todo(p[0], "WARNING opportunity for kvmalloc")
+
+@script: python depends on report@
+p << kvfree.p;
+@@
+
+coccilib.report.print_report(p[0], "WARNING opportunity for kvfree")
+
+@script: python depends on org@
+p << kvfree.p;
+@@
+
+coccilib.org.print_todo(p[0], "WARNING opportunity for kvfree")