From: Aaron Thompson dev@aaront.org

If bt_debugfs is not created successfully, which happens if either CONFIG_DEBUG_FS or CONFIG_DEBUG_FS_ALLOW_ALL is unset, then iso_init() returns early and does not set iso_inited to true. This means that a subsequent call to iso_init() will result in duplicate calls to proto_register(), bt_sock_register(), etc.

With CONFIG_LIST_HARDENED and CONFIG_BUG_ON_DATA_CORRUPTION enabled, the duplicate call to proto_register() triggers this BUG():

list_add double add: new=ffffffffc0b280d0, prev=ffffffffbab56250, next=ffffffffc0b280d0. ------------[ cut here ]------------ kernel BUG at lib/list_debug.c:35! Oops: invalid opcode: 0000 [#1] PREEMPT SMP PTI CPU: 2 PID: 887 Comm: bluetoothd Not tainted 6.10.11-1-ao-desktop #1 RIP: 0010:__list_add_valid_or_report+0x9a/0xa0 ... __list_add_valid_or_report+0x9a/0xa0 proto_register+0x2b5/0x340 iso_init+0x23/0x150 [bluetooth] set_iso_socket_func+0x68/0x1b0 [bluetooth] kmem_cache_free+0x308/0x330 hci_sock_sendmsg+0x990/0x9e0 [bluetooth] __sock_sendmsg+0x7b/0x80 sock_write_iter+0x9a/0x110 do_iter_readv_writev+0x11d/0x220 vfs_writev+0x180/0x3e0 do_writev+0xca/0x100 ...

This change removes the early return. The check for iso_debugfs being NULL was unnecessary, it is always NULL when iso_inited is false.

Cc: stable@vger.kernel.org Fixes: ccf74f2390d6 ("Bluetooth: Add BTPROTO_ISO socket type") Signed-off-by: Aaron Thompson dev@aaront.org --- net/bluetooth/iso.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c index d5e00d0dd1a0..c9eefb43bf47 100644 --- a/net/bluetooth/iso.c +++ b/net/bluetooth/iso.c @@ -2301,13 +2301,9 @@ int iso_init(void)

hci_register_cb(&iso_cb);

- if (IS_ERR_OR_NULL(bt_debugfs)) - return 0; - - if (!iso_debugfs) { + if (!IS_ERR_OR_NULL(bt_debugfs)) iso_debugfs = debugfs_create_file("iso", 0444, bt_debugfs, NULL, &iso_debugfs_fops); - }

iso_inited = true;