Subject: [PATCH net v2] s390/iucv: Fix vargs handling in iucv_alloc_device()

From: Alexandra Winter <[email-masked]>
Date: Tue, 20 Aug 2024 10:45:28 +0200

iucv_alloc_device() gets a format string and a varying number of
arguments. This is incorrectly forwarded by calling dev_set_name() with
the format string and a va_list, while dev_set_name() expects also a
varying number of arguments.

Symptoms:
Corrupted iucv device names, which can result in log messages like:
sysfs: cannot create duplicate filename '/devices/iucv/hvc_iucv1827699952'

Fixes: 4452e8ef8c36 ("s390/iucv: Provide iucv_alloc_device() / iucv_release_device()")
Link: https://bugzilla.suse.com/show_bug.cgi?id=1228425
Signed-off-by: Alexandra Winter <[email-masked]>
Reviewed-by: Thorsten Winkler <[email-masked]>
---
Discussion of v1:
Link: https://lore.kernel.org/all/2024081326-shifter-output-cb8f@gregkh/T/#mf8ae979de8acdc01f7ede0b94af6f2e110eea209
Reported-by: kernel test robot <[email-masked]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email-masked]/
Vasily Gorbik asked me to send this version via the netdev mailing list.
---
 net/iucv/iucv.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/iucv/iucv.c b/net/iucv/iucv.c
index 1e42e13ad24e..2e615641a4e5 100644
--- a/net/iucv/iucv.c
+++ b/net/iucv/iucv.c
@@ -86,13 +86,15 @@ struct device *iucv_alloc_device(const struct attribute_group **attrs,
 {
 	struct device *dev;
 	va_list vargs;
+	char buf[20];
 	int rc;
 
 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 	if (!dev)
 		goto out_error;
 	va_start(vargs, fmt);
-	rc = dev_set_name(dev, fmt, vargs);
+	vsnprintf(buf, sizeof(buf), fmt, vargs);
+	rc = dev_set_name(dev, buf);
 	va_end(vargs);
 	if (rc)
 		goto out_error;
-- 
2.39.3 (Apple Git-146)