Re: [Regression] depmod fails on kernel 6.17.1 rc1

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

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On Thu, 6 Nov 2025, Ilpo Järvinen wrote:

> On Thu, 6 Nov 2025, Borislav Petkov wrote:
> 
> > On Thu, Nov 06, 2025 at 06:15:57PM +0200, Andy Shevchenko wrote:
> > > > So I'm seeing this with an allmodconfig build too:
> > 			       ^^^^^^^^^^^^
> > > > depmod: ERROR: Cycle detected: 8250 -> 8250_base -> 8250
> > > > depmod: ERROR: Found 2 modules in dependency cycles!
> > > 
> > > I'm surprised it took so long to people to start complaining.
> > > 
> > > So, some of those are modules? Can you share the
> > > 
> > > 	grep 8250 .config
> > > 
> > > part?
> > 
> > See above.
> 
> https://lore.kernel.org/all/87frc3sd8d.fsf@posteo.net/
> 
> I wonder if 8250_rsa.o can be put into 8250_base.o where most of its 
> callers are anyway?

This seems to resolve the build issue for me:

--
From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>
Subject: [PATCH 1/1] serial: 8250: Fix 8250_rsa symbol loop

make allmodconfig build fails due to dependency loop:

  depmod: ERROR: Cycle detected: 8250 -> 8250_base -> 8250
  depmod: ERROR: Found 2 modules in dependency cycles!

Break dependency loop by moving 8250_rsa.o into 8250_base and by
passing univ8250_port_base_ops to univ8250_rsa_support() that can make
a local copy of it.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Alex Davis <alex47794@gmail.com>
Fixes: b20d6576cdb3 ("serial: 8250: export RSA functions")
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 drivers/tty/serial/8250/8250.h          |  2 +-
 drivers/tty/serial/8250/8250_platform.c |  2 +-
 drivers/tty/serial/8250/8250_rsa.c      | 18 +++++++++---------
 drivers/tty/serial/8250/Makefile        |  2 +-
 4 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index 58e64c4e1e3a..bd294fbf0e65 100644
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -322,7 +322,7 @@ static inline void serial8250_pnp_exit(void) { }
 #endif
 
 #ifdef CONFIG_SERIAL_8250_RSA
-void univ8250_rsa_support(struct uart_ops *ops);
+void univ8250_rsa_support(struct uart_ops *ops, const struct uart_ops *core_ops);
 void rsa_enable(struct uart_8250_port *up);
 void rsa_disable(struct uart_8250_port *up);
 void rsa_autoconfig(struct uart_8250_port *up);
diff --git a/drivers/tty/serial/8250/8250_platform.c b/drivers/tty/serial/8250/8250_platform.c
index b27981340e76..fe7ec440ffa5 100644
--- a/drivers/tty/serial/8250/8250_platform.c
+++ b/drivers/tty/serial/8250/8250_platform.c
@@ -75,7 +75,7 @@ static void __init __serial8250_isa_init_ports(void)
 
 	/* chain base port ops to support Remote Supervisor Adapter */
 	univ8250_port_ops = *univ8250_port_base_ops;
-	univ8250_rsa_support(&univ8250_port_ops);
+	univ8250_rsa_support(&univ8250_port_ops, univ8250_port_base_ops);
 
 	if (share_irqs)
 		irqflag = IRQF_SHARED;
diff --git a/drivers/tty/serial/8250/8250_rsa.c b/drivers/tty/serial/8250/8250_rsa.c
index 40a3dbd9e452..d76d1be86625 100644
--- a/drivers/tty/serial/8250/8250_rsa.c
+++ b/drivers/tty/serial/8250/8250_rsa.c
@@ -14,6 +14,8 @@
 static unsigned long probe_rsa[PORT_RSA_MAX];
 static unsigned int probe_rsa_count;
 
+static const struct uart_ops *core_port_base_ops;
+
 static int rsa8250_request_resource(struct uart_8250_port *up)
 {
 	struct uart_port *port = &up->port;
@@ -67,7 +69,7 @@ static void univ8250_config_port(struct uart_port *port, int flags)
 		}
 	}
 
-	univ8250_port_base_ops->config_port(port, flags);
+	core_port_base_ops->config_port(port, flags);
 
 	if (port->type != PORT_RSA && up->probe & UART_PROBE_RSA)
 		rsa8250_release_resource(up);
@@ -78,11 +80,11 @@ static int univ8250_request_port(struct uart_port *port)
 	struct uart_8250_port *up = up_to_u8250p(port);
 	int ret;
 
-	ret = univ8250_port_base_ops->request_port(port);
+	ret = core_port_base_ops->request_port(port);
 	if (ret == 0 && port->type == PORT_RSA) {
 		ret = rsa8250_request_resource(up);
 		if (ret < 0)
-			univ8250_port_base_ops->release_port(port);
+			core_port_base_ops->release_port(port);
 	}
 
 	return ret;
@@ -94,15 +96,17 @@ static void univ8250_release_port(struct uart_port *port)
 
 	if (port->type == PORT_RSA)
 		rsa8250_release_resource(up);
-	univ8250_port_base_ops->release_port(port);
+	core_port_base_ops->release_port(port);
 }
 
-void univ8250_rsa_support(struct uart_ops *ops)
+void univ8250_rsa_support(struct uart_ops *ops, const struct uart_ops *core_ops)
 {
+	core_port_base_ops = core_ops;
 	ops->config_port  = univ8250_config_port;
 	ops->request_port = univ8250_request_port;
 	ops->release_port = univ8250_release_port;
 }
+EXPORT_SYMBOL_FOR_MODULES(univ8250_rsa_support, "8250");
 
 module_param_hw_array(probe_rsa, ulong, ioport, &probe_rsa_count, 0444);
 MODULE_PARM_DESC(probe_rsa, "Probe I/O ports for RSA");
@@ -146,7 +150,6 @@ void rsa_enable(struct uart_8250_port *up)
 	if (up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16)
 		serial_out(up, UART_RSA_FRR, 0);
 }
-EXPORT_SYMBOL_FOR_MODULES(rsa_enable, "8250_base");
 
 /*
  * Attempts to turn off the RSA FIFO and resets the RSA board back to 115kbps compat mode. It is
@@ -178,7 +181,6 @@ void rsa_disable(struct uart_8250_port *up)
 	if (result)
 		up->port.uartclk = SERIAL_RSA_BAUD_BASE_LO * 16;
 }
-EXPORT_SYMBOL_FOR_MODULES(rsa_disable, "8250_base");
 
 void rsa_autoconfig(struct uart_8250_port *up)
 {
@@ -191,7 +193,6 @@ void rsa_autoconfig(struct uart_8250_port *up)
 	if (__rsa_enable(up))
 		up->port.type = PORT_RSA;
 }
-EXPORT_SYMBOL_FOR_MODULES(rsa_autoconfig, "8250_base");
 
 void rsa_reset(struct uart_8250_port *up)
 {
@@ -200,7 +201,6 @@ void rsa_reset(struct uart_8250_port *up)
 
 	serial_out(up, UART_RSA_FRR, 0);
 }
-EXPORT_SYMBOL_FOR_MODULES(rsa_reset, "8250_base");
 
 #ifdef CONFIG_SERIAL_8250_DEPRECATED_OPTIONS
 #ifndef MODULE
diff --git a/drivers/tty/serial/8250/Makefile b/drivers/tty/serial/8250/Makefile
index 513a0941c284..9ec4d5fe64de 100644
--- a/drivers/tty/serial/8250/Makefile
+++ b/drivers/tty/serial/8250/Makefile
@@ -7,7 +7,6 @@ obj-$(CONFIG_SERIAL_8250)		+= 8250.o
 8250-y					:= 8250_core.o
 8250-y					+= 8250_platform.o
 8250-$(CONFIG_SERIAL_8250_PNP)		+= 8250_pnp.o
-8250-$(CONFIG_SERIAL_8250_RSA)		+= 8250_rsa.o
 
 obj-$(CONFIG_SERIAL_8250)		+= 8250_base.o
 8250_base-y				:= 8250_port.o
@@ -15,6 +14,7 @@ obj-$(CONFIG_SERIAL_8250)		+= 8250_base.o
 8250_base-$(CONFIG_SERIAL_8250_DWLIB)	+= 8250_dwlib.o
 8250_base-$(CONFIG_SERIAL_8250_FINTEK)	+= 8250_fintek.o
 8250_base-$(CONFIG_SERIAL_8250_PCILIB)	+= 8250_pcilib.o
+8250_base-$(CONFIG_SERIAL_8250_RSA)	+= 8250_rsa.o
 
 obj-$(CONFIG_SERIAL_8250_CONSOLE)	+= 8250_early.o
 

base-commit: 719f3df3e113e03d2c8cf324827da1fd17a9bd8f
-- 
2.39.5