Commit 7215e455 authored by Gui-Dong Han's avatar Gui-Dong Han Committed by Greg Kroah-Hartman
Browse files

soundwire: debugfs: initialize firmware_file to empty string 



Passing NULL to debugfs_create_str() causes a NULL pointer dereference,
and creating debugfs nodes with NULL string pointers is no longer
permitted.

Additionally, firmware_file is a global pointer. Previously, adding every
new slave blindly overwrote it with NULL.

Fix these issues by initializing firmware_file to an allocated empty
string once in the subsystem init path (sdw_debugfs_init), and freeing
it in the exit path. Existing driver code handles empty strings
correctly.

Fixes: fe46d2a4 ("soundwire: debugfs: add interface to read/write commands")
Reported-by: default avataryangshiguang <yangshiguang@xiaomi.com>
Closes: https://lore.kernel.org/lkml/17647e4c.d461.19b46144a4e.Coremail.yangshiguang1011@163.com/


Signed-off-by: default avatarGui-Dong Han <hanguidong02@gmail.com>
Link: https://patch.msgid.link/20260323085930.88894-4-hanguidong02@gmail.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4afc929c

drivers/soundwire/debugfs.c

+7 −2
Original line number Diff line number Diff line
@@ -358,7 +358,7 @@ void sdw_slave_debugfs_init(struct sdw_slave *slave) 
	debugfs_create_file("go", 0200, d, slave, &cmd_go_fops);



	debugfs_create_file("read_buffer", 0400, d, slave, &read_buffer_fops);

	firmware_file = NULL;

	if (firmware_file)

		debugfs_create_str("firmware_file", 0200, d, &firmware_file);



	slave->debugfs = d;
@@ -371,10 +371,15 @@ void sdw_slave_debugfs_exit(struct sdw_slave *slave) 


void sdw_debugfs_init(void)

{

	if (!firmware_file)

		firmware_file = kstrdup("", GFP_KERNEL);



	sdw_debugfs_root = debugfs_create_dir("soundwire", NULL);

}



void sdw_debugfs_exit(void)

{

	debugfs_remove_recursive(sdw_debugfs_root);

	kfree(firmware_file);

	firmware_file = NULL;

}