Bluetooth: ISO: Fix multiple init when debugfs is disabled

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: Fix multiple init when debugfs is disabled 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.

References

• https://git.kernel.org/stable/c/fa4b832c5a6ec35023a1b997cf658c436619c752
• https://git.kernel.org/stable/c/8fb8e912afb4c47dec12ea9a5853e7a8db95816f
• https://git.kernel.org/stable/c/adf1b179c2ff8073c24bf87e5a605fcc5a09798b
• https://git.kernel.org/stable/c/a9b7b535ba192c6b77e6c15a4c82d853163eab8c