[PATCH] platform/x86: dell-smo8800: Suppress bind attributes of the platform driver

[Rosen Penev <rosenp@gmail.com>]

struct smo8800_device, which holds the misc device and its wait
queue, is allocated with devm_kzalloc() and freed when the device is
unbound. misc_deregister() does not close files that are already
open, so if /dev/freefall is open when the driver is unbound through
sysfs, a reader blocked in smo8800_misc_read() is left sleeping on a
wait queue in freed memory, and smo8800_misc_release() later clears a
bit in it.

Module removal is not affected, since an open /dev/freefall holds a
reference to the module. Unbinding by hand is the only other way to
remove the device, and it is not useful, so hide the bind and unbind
files.

Fixes: 4738d8aabe89 ("platform: x86: dell-smo8800: Dell Latitude freefall driver (ACPI SMO8800/SMO8810)")
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
Developed with the help of an AI coding assistant (Claude Opus 5.5),
which found the issue and drafted the fix; I reviewed it and am
responsible for it. Builds cleanly with W=1.
Tested on a Dell Precision M4800 running v7.2.15, using the equivalent
backports built as out-of-tree modules: the driver loads and the bind/unbind files are gone.

 drivers/platform/x86/dell/dell-smo8800.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/platform/x86/dell/dell-smo8800.c b/drivers/platform/x86/dell/dell-smo8800.c
index e056664656a7..aae9a028d69e 100644
--- a/drivers/platform/x86/dell/dell-smo8800.c
+++ b/drivers/platform/x86/dell/dell-smo8800.c
@@ -169,6 +169,7 @@ static struct platform_driver smo8800_driver = {
 	.driver = {
 		.name = DRIVER_NAME,
 		.acpi_match_table = smo8800_ids,
+		.suppress_bind_attrs = true,
 	},
 };
 module_platform_driver(smo8800_driver);

base-commit: 2800868f63227c8237d70c41e70d441c919620d6
-- 
2.56.0