From: Aaron Thompson <dev@aaront.org>

If iso_init() has been called, iso_exit() must be called on module
unload. Without that, the struct proto that iso_init() registered with
proto_register() becomes invalid, which could cause unpredictable
problems later. In my case, with CONFIG_LIST_HARDENED and
CONFIG_BUG_ON_DATA_CORRUPTION enabled, loading the module again usually
triggers this BUG():

  list_add corruption. next->prev should be prev (ffffffffb5355fd0),
    but was 0000000000000068. (next=ffffffffc0a010d0).
  ------------[ cut here ]------------
  kernel BUG at lib/list_debug.c:29!
  Oops: invalid opcode: 0000 [#1] PREEMPT SMP PTI
  CPU: 1 PID: 4159 Comm: modprobe Not tainted 6.10.11-4+bt2-ao-desktop #1
  RIP: 0010:__list_add_valid_or_report+0x61/0xa0
  ...
    __list_add_valid_or_report+0x61/0xa0
    proto_register+0x299/0x320
    hci_sock_init+0x16/0xc0 [bluetooth]
    bt_init+0x68/0xd0 [bluetooth]
    __pfx_bt_init+0x10/0x10 [bluetooth]
    do_one_initcall+0x80/0x2f0
    do_init_module+0x8b/0x230
    __do_sys_init_module+0x15f/0x190
    do_syscall_64+0x68/0x110
  ...

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

diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index e4f564d6f6fb..78a164fab3e1 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -10487,6 +10487,7 @@ int mgmt_init(void)
 
 void mgmt_exit(void)
 {
+	iso_exit();
 	hci_mgmt_chan_unregister(&chan);
 }
 
-- 
2.39.5

Hi Aaron,

On Thu, Oct 3, 2024 at 8:31 PM Aaron Thompson <dev@aaront.org> wrote:
>
> From: Aaron Thompson <dev@aaront.org>
>
> If iso_init() has been called, iso_exit() must be called on module
> unload. Without that, the struct proto that iso_init() registered with
> proto_register() becomes invalid, which could cause unpredictable
> problems later. In my case, with CONFIG_LIST_HARDENED and
> CONFIG_BUG_ON_DATA_CORRUPTION enabled, loading the module again usually
> triggers this BUG():
>
>   list_add corruption. next->prev should be prev (ffffffffb5355fd0),
>     but was 0000000000000068. (next=ffffffffc0a010d0).
>   ------------[ cut here ]------------
>   kernel BUG at lib/list_debug.c:29!
>   Oops: invalid opcode: 0000 [#1] PREEMPT SMP PTI
>   CPU: 1 PID: 4159 Comm: modprobe Not tainted 6.10.11-4+bt2-ao-desktop #1
>   RIP: 0010:__list_add_valid_or_report+0x61/0xa0
>   ...
>     __list_add_valid_or_report+0x61/0xa0
>     proto_register+0x299/0x320
>     hci_sock_init+0x16/0xc0 [bluetooth]
>     bt_init+0x68/0xd0 [bluetooth]
>     __pfx_bt_init+0x10/0x10 [bluetooth]
>     do_one_initcall+0x80/0x2f0
>     do_init_module+0x8b/0x230
>     __do_sys_init_module+0x15f/0x190
>     do_syscall_64+0x68/0x110
>   ...
>
> Cc: stable@vger.kernel.org
> Fixes: ccf74f2390d6 ("Bluetooth: Add BTPROTO_ISO socket type")
> Signed-off-by: Aaron Thompson <dev@aaront.org>
> ---
>  net/bluetooth/mgmt.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
> index e4f564d6f6fb..78a164fab3e1 100644
> --- a/net/bluetooth/mgmt.c
> +++ b/net/bluetooth/mgmt.c
> @@ -10487,6 +10487,7 @@ int mgmt_init(void)
>
>  void mgmt_exit(void)
>  {
> +       iso_exit();
>         hci_mgmt_chan_unregister(&chan);
>  }
>
> --
> 2.39.5

I had it under bt_exit with the rest of the exit functions so that we
don't have to move it once ISO sockets become stable.


-- 
Luiz Augusto von Dentz

Hi Luiz,

On 10/4/24 12:30, Luiz Augusto von Dentz wrote:
> 
> I had it under bt_exit with the rest of the exit functions so that we
> don't have to move it once ISO sockets become stable.
> 

Sure thing. I was just guessing based on where the call to iso_init() 
is. Thanks for the review!

-- Aaron