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, 161 insertions, 0 deletions

diff --git a/rust/helpers/io.c b/rust/helpers/io.c
new file mode 100644
index 000000000..308950aae
--- /dev/null
+++ b/rust/helpers/io.c
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/io.h>
+#include <linux/ioport.h>
+
+#ifdef CONFIG_HAS_IOMEM
+__rust_helper void __iomem *rust_helper_ioremap(phys_addr_t offset, size_t size)
+{
+	return ioremap(offset, size);
+}
+
+__rust_helper void __iomem *rust_helper_ioremap_np(phys_addr_t offset,
+						   size_t size)
+{
+	return ioremap_np(offset, size);
+}
+
+__rust_helper void rust_helper_iounmap(void __iomem *addr)
+{
+	iounmap(addr);
+}
+#endif /* CONFIG_HAS_IOMEM */
+
+__rust_helper void rust_helper_memcpy_fromio(void *dst,
+					     const volatile void __iomem *src,
+					     size_t count)
+{
+	memcpy_fromio(dst, src, count);
+}
+
+__rust_helper void rust_helper_memcpy_toio(volatile void __iomem *dst,
+					   const void *src, size_t count)
+{
+	memcpy_toio(dst, src, count);
+}
+
+__rust_helper u8 rust_helper_readb(const void __iomem *addr)
+{
+	return readb(addr);
+}
+
+__rust_helper u16 rust_helper_readw(const void __iomem *addr)
+{
+	return readw(addr);
+}
+
+__rust_helper u32 rust_helper_readl(const void __iomem *addr)
+{
+	return readl(addr);
+}
+
+#ifdef CONFIG_64BIT
+__rust_helper u64 rust_helper_readq(const void __iomem *addr)
+{
+	return readq(addr);
+}
+#endif
+
+__rust_helper void rust_helper_writeb(u8 value, void __iomem *addr)
+{
+	writeb(value, addr);
+}
+
+__rust_helper void rust_helper_writew(u16 value, void __iomem *addr)
+{
+	writew(value, addr);
+}
+
+__rust_helper void rust_helper_writel(u32 value, void __iomem *addr)
+{
+	writel(value, addr);
+}
+
+#ifdef CONFIG_64BIT
+__rust_helper void rust_helper_writeq(u64 value, void __iomem *addr)
+{
+	writeq(value, addr);
+}
+#endif
+
+__rust_helper u8 rust_helper_readb_relaxed(const void __iomem *addr)
+{
+	return readb_relaxed(addr);
+}
+
+__rust_helper u16 rust_helper_readw_relaxed(const void __iomem *addr)
+{
+	return readw_relaxed(addr);
+}
+
+__rust_helper u32 rust_helper_readl_relaxed(const void __iomem *addr)
+{
+	return readl_relaxed(addr);
+}
+
+#ifdef CONFIG_64BIT
+__rust_helper u64 rust_helper_readq_relaxed(const void __iomem *addr)
+{
+	return readq_relaxed(addr);
+}
+#endif
+
+__rust_helper void rust_helper_writeb_relaxed(u8 value, void __iomem *addr)
+{
+	writeb_relaxed(value, addr);
+}
+
+__rust_helper void rust_helper_writew_relaxed(u16 value, void __iomem *addr)
+{
+	writew_relaxed(value, addr);
+}
+
+__rust_helper void rust_helper_writel_relaxed(u32 value, void __iomem *addr)
+{
+	writel_relaxed(value, addr);
+}
+
+#ifdef CONFIG_64BIT
+__rust_helper void rust_helper_writeq_relaxed(u64 value, void __iomem *addr)
+{
+	writeq_relaxed(value, addr);
+}
+#endif
+
+__rust_helper resource_size_t rust_helper_resource_size(struct resource *res)
+{
+	return resource_size(res);
+}
+
+__rust_helper struct resource *
+rust_helper_request_mem_region(resource_size_t start, resource_size_t n,
+			       const char *name)
+{
+	return request_mem_region(start, n, name);
+}
+
+__rust_helper void rust_helper_release_mem_region(resource_size_t start,
+						  resource_size_t n)
+{
+	release_mem_region(start, n);
+}
+
+__rust_helper struct resource *rust_helper_request_region(resource_size_t start,
+							  resource_size_t n,
+							  const char *name)
+{
+	return request_region(start, n, name);
+}
+
+__rust_helper struct resource *
+rust_helper_request_muxed_region(resource_size_t start, resource_size_t n,
+				 const char *name)
+{
+	return request_muxed_region(start, n, name);
+}
+
+__rust_helper void rust_helper_release_region(resource_size_t start,
+					      resource_size_t n)
+{
+	release_region(start, n);
+}