linux-kernel - [PATCH] tty: nozomi: Return an error when failing to create the sysfs

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Date:   Thu,  9 Jun 2022 16:31:33 +0800
From:   Zheyu Ma <zheyuma97@...il.com>
To:     gregkh@...uxfoundation.org, jirislaby@...nel.org, fseidel@...e.de
Cc:     linux-kernel@...r.kernel.org, Zheyu Ma <zheyuma97@...il.com>
Subject: [PATCH] tty: nozomi: Return an error when failing to create the sysfs

The driver does not handle the error of the creation of sysfs, resulting
in duplicate file names being created.

The following log can reveal it:

[   52.907211] sysfs: cannot create duplicate filename '/devices/pci0000:00/0000:00:05.0/card_type'
[   52.907224] Call Trace:
[   52.907269]  sysfs_add_file_mode_ns+0x23f/0x2b0
[   52.907281]  sysfs_create_file_ns+0xe9/0x170
[   52.907321]  nozomi_card_init+0x97f/0x12c0 [nozomi]

Fix this bug by returning an error when failing to create the sysfs.

Fixes: 20fd1e3bea55 ("nozomi driver")
Signed-off-by: Zheyu Ma <zheyuma97@...il.com>
---
 drivers/tty/nozomi.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/nozomi.c b/drivers/tty/nozomi.c
index 0454c78deee6..d0ad1b9898f5 100644
--- a/drivers/tty/nozomi.c
+++ b/drivers/tty/nozomi.c
@@ -1282,14 +1282,26 @@ static ssize_t open_ttys_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RO(open_ttys);
 
-static void make_sysfs_files(struct nozomi *dc)
+static int make_sysfs_files(struct nozomi *dc)
 {
-	if (device_create_file(&dc->pdev->dev, &dev_attr_card_type))
+	int err;
+
+	err = device_create_file(&dc->pdev->dev, &dev_attr_card_type);
+	if (err) {
 		dev_err(&dc->pdev->dev,
 			"Could not create sysfs file for card_type\n");
-	if (device_create_file(&dc->pdev->dev, &dev_attr_open_ttys))
+		return err;
+	}
+
+	err = device_create_file(&dc->pdev->dev, &dev_attr_open_ttys);
+	if (err) {
+		device_remove_file(&dc->pdev->dev, &dev_attr_card_type);
 		dev_err(&dc->pdev->dev,
 			"Could not create sysfs file for open_ttys\n");
+		return err;
+	}
+
+	return 0;
 }
 
 static void remove_sysfs_files(struct nozomi *dc)
@@ -1383,7 +1395,9 @@ static int nozomi_card_init(struct pci_dev *pdev,
 
 	DBG1("base_addr: %p", dc->base_addr);
 
-	make_sysfs_files(dc);
+	ret = make_sysfs_files(dc);
+	if (ret)
+		goto err_free_irq;
 
 	dc->index_start = ndev_idx * MAX_PORT;
 	ndevs[ndev_idx] = dc;
@@ -1420,6 +1434,8 @@ static int nozomi_card_init(struct pci_dev *pdev,
 		tty_unregister_device(ntty_driver, dc->index_start + i);
 		tty_port_destroy(&dc->port[i].port);
 	}
+	remove_sysfs_files(dc);
+err_free_irq:
 	free_irq(pdev->irq, dc);
 err_free_all_kfifo:
 	i = MAX_PORT;
-- 
2.25.1