tty: mxser: improve error handling in mxser_probe() and mxser_module_init()

1. Currently mxser_probe() and mxser_module_init() ignore errors
that can happen in tty_port_register_device().
2. mxser_module_init() does not deallocate resources allocated in mxser_get_ISA_conf()
if mxser_initbrd() failed.

The patch adds proper error handling in all the cases.
Also it moves free_irq() from mxser_release_ISA_res() to mxser_board_remove(),
since it makes mxser_release_ISA_res() a counterpart for mxser_get_ISA_conf(),
while free_irq() is relevant to both ISA and PCI boards.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 35 insertions, 7 deletions

diff --git a/drivers/tty/mxser.c b/drivers/tty/mxser.c
index ad34a202a34d..484b6a3c9b03 100644
--- a/drivers/tty/mxser.c
+++ b/drivers/tty/mxser.c
@@ -2364,7 +2364,6 @@ static void mxser_release_vector(struct mxser_board *brd)
 
 static void mxser_release_ISA_res(struct mxser_board *brd)
 {
-        free_irq(brd->irq, brd);
         release_region(brd->ports[0].ioaddr, 8 * brd->info->nports);
         mxser_release_vector(brd);
 }
@@ -2430,6 +2429,7 @@ static void mxser_board_remove(struct mxser_board *brd)
                 tty_unregister_device(mxvar_sdriver, brd->idx + i);
                 tty_port_destroy(&brd->ports[i].port);
         }
+        free_irq(brd->irq, brd);
 }
 
 static int __init mxser_get_ISA_conf(int cap, struct mxser_board *brd)
@@ -2554,6 +2554,7 @@ static int mxser_probe(struct pci_dev *pdev,
         struct mxser_board *brd;
         unsigned int i, j;
         unsigned long ioaddress;
+        struct device *tty_dev;
         int retval = -EINVAL;
 
         for (i = 0; i < MXSER_BOARDS; i++)
@@ -2637,13 +2638,25 @@ static int mxser_probe(struct pci_dev *pdev,
         if (retval)
                 goto err_rel3;
 
-        for (i = 0; i < brd->info->nports; i++)
-                tty_port_register_device(&brd->ports[i].port, mxvar_sdriver,
-                                brd->idx + i, &pdev->dev);
+        for (i = 0; i < brd->info->nports; i++) {
+                tty_dev = tty_port_register_device(&brd->ports[i].port,
+                                mxvar_sdriver, brd->idx + i, &pdev->dev);
+                if (IS_ERR(tty_dev)) {
+                        retval = PTR_ERR(tty_dev);
+                        for (i--; i >= 0; i--)
+                                tty_unregister_device(mxvar_sdriver,
+                                        brd->idx + i);
+                        goto err_relbrd;
+                }
+        }
 
         pci_set_drvdata(pdev, brd);
 
         return 0;
+err_relbrd:
+        for (i = 0; i < brd->info->nports; i++)
+                tty_port_destroy(&brd->ports[i].port);
+        free_irq(brd->irq, brd);
 err_rel3:
         pci_release_region(pdev, 3);
 err_zero:
@@ -2665,7 +2678,6 @@ static void mxser_remove(struct pci_dev *pdev)
 
         mxser_board_remove(brd);
 
-        free_irq(pdev->irq, brd);
         pci_release_region(pdev, 2);
         pci_release_region(pdev, 3);
         pci_disable_device(pdev);
@@ -2683,6 +2695,7 @@ static struct pci_driver mxser_driver = {
 static int __init mxser_module_init(void)
 {
         struct mxser_board *brd;
+        struct device *tty_dev;
         unsigned int b, i, m;
         int retval;
 
@@ -2728,14 +2741,29 @@ static int __init mxser_module_init(void)
 
                 /* mxser_initbrd will hook ISR. */
                 if (mxser_initbrd(brd, NULL) < 0) {
+                        mxser_release_ISA_res(brd);
                         brd->info = NULL;
                         continue;
                 }
 
                 brd->idx = m * MXSER_PORTS_PER_BOARD;
-                for (i = 0; i < brd->info->nports; i++)
-                        tty_port_register_device(&brd->ports[i].port,
+                for (i = 0; i < brd->info->nports; i++) {
+                        tty_dev = tty_port_register_device(&brd->ports[i].port,
                                         mxvar_sdriver, brd->idx + i, NULL);
+                        if (IS_ERR(tty_dev)) {
+                                for (i--; i >= 0; i--)
+                                        tty_unregister_device(mxvar_sdriver,
+                                                brd->idx + i);
+                                for (i = 0; i < brd->info->nports; i++)
+                                        tty_port_destroy(&brd->ports[i].port);
+                                free_irq(brd->irq, brd);
+                                mxser_release_ISA_res(brd);
+                                brd->info = NULL;
+                                break;
+                        }
+                }
+                if (brd->info == NULL)
+                        continue;
 
                 m++;
         }