[PATCH] hwmon: (dell-smm) Fix warning on /proc/i8k creation error

[PATCH] hwmon: (dell-smm) Fix warning on /proc/i8k creation error

[Armin Wolf]

commit dbd3e6eaf3d813939b28e8a66e29d81cdc836445 upstream.

The removal function is called regardless of whether
/proc/i8k was created successfully or not, the later
causing a WARN() on module removal.
Fix that by only calling the removal function
if /proc/i8k was created successfully.

Since the original patch depends on the driver
registering a platform device, the backported patch
stores the return value of proc_create() and only
calls proc_remove_entry() on exit if proc_create()
was successful.

Tested on a Inspiron 3505 for kernel 5.10.

Cc: <stable@vger.kernel.org> # 5.10.x
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
---
 drivers/hwmon/dell-smm-hwmon.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
index 63b74e781c5d..87f401100466 100644
--- a/drivers/hwmon/dell-smm-hwmon.c
+++ b/drivers/hwmon/dell-smm-hwmon.c
@@ -603,15 +603,18 @@ static const struct proc_ops i8k_proc_ops = {
 	.proc_ioctl	= i8k_ioctl,
 };

+static struct proc_dir_entry *entry;
+
 static void __init i8k_init_procfs(void)
 {
 	/* Register the proc entry */
-	proc_create("i8k", 0, NULL, &i8k_proc_ops);
+	entry = proc_create("i8k", 0, NULL, &i8k_proc_ops);
 }

 static void __exit i8k_exit_procfs(void)
 {
-	remove_proc_entry("i8k", NULL);
+	if (entry)
+		remove_proc_entry("i8k", NULL);
 }

 #else
--
2.30.2

Re: [PATCH] hwmon: (dell-smm) Fix warning on /proc/i8k creation error

[Greg KH]

On Tue, Dec 14, 2021 at 10:00:47PM +0100, Armin Wolf wrote:
> commit dbd3e6eaf3d813939b28e8a66e29d81cdc836445 upstream.
> 
> The removal function is called regardless of whether
> /proc/i8k was created successfully or not, the later
> causing a WARN() on module removal.
> Fix that by only calling the removal function
> if /proc/i8k was created successfully.
> 
> Since the original patch depends on the driver
> registering a platform device, the backported patch
> stores the return value of proc_create() and only
> calls proc_remove_entry() on exit if proc_create()
> was successful.
> 
> Tested on a Inspiron 3505 for kernel 5.10.
> 
> Cc: <stable@vger.kernel.org> # 5.10.x
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
> ---
>  drivers/hwmon/dell-smm-hwmon.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)

All now queued up, thanks.

greg k-h

[PATCH] hwmon: (dell-smm) Fix warning on /proc/i8k creation error

[Armin Wolf]

commit dbd3e6eaf3d813939b28e8a66e29d81cdc836445 upstream.

The removal function is called regardless of whether
/proc/i8k was created successfully or not, the later
causing a WARN() on module removal.
Fix that by only calling the removal function
if /proc/i8k was created successfully.

Since the original patch depends on the driver
registering a platform device, the backported patch
stores the return value of proc_create() and only
calls proc_remove_entry() on exit if proc_create()
was successful.

Tested on a Inspiron 3505 for kernels 4.19/4.9.

Cc: <stable@vger.kernel.org> # 5.4.x
Cc: <stable@vger.kernel.org> # 4.x.x
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
---
 drivers/hwmon/dell-smm-hwmon.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
index 35c00420d855..2eaed0008f37 100644
--- a/drivers/hwmon/dell-smm-hwmon.c
+++ b/drivers/hwmon/dell-smm-hwmon.c
@@ -588,15 +588,18 @@ static const struct file_operations i8k_fops = {
 	.unlocked_ioctl	= i8k_ioctl,
 };

+static struct proc_dir_entry *entry;
+
 static void __init i8k_init_procfs(void)
 {
 	/* Register the proc entry */
-	proc_create("i8k", 0, NULL, &i8k_fops);
+	entry = proc_create("i8k", 0, NULL, &i8k_fops);
 }

 static void __exit i8k_exit_procfs(void)
 {
-	remove_proc_entry("i8k", NULL);
+	if (entry)
+		remove_proc_entry("i8k", NULL);
 }

 #else
--
2.30.2