This is a note to let you know that I've just added the patch titled
Bluetooth: hci_serdev: call init_rwsem() before p->open()
to the 5.17-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bluetooth-hci_serdev-call-init_rwsem-before-p-open.patch
and it can be found in the queue-5.17 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 6bd0ce08f955176725dd03765ffc71cd400ef828
Author: Pavel Skripkin <paskripkin@xxxxxxxxx>
Date: Thu Jan 13 16:27:04 2022 +0300
Bluetooth: hci_serdev: call init_rwsem() before p->open()
[ Upstream commit 9d7cbe2b9cf5f650067df4f402fdd799d4bbb4e1 ]
kvartet reported, that hci_uart_tx_wakeup() uses uninitialized rwsem.
The problem was in wrong place for percpu_init_rwsem() call.
hci_uart_proto::open() may register a timer whose callback may call
hci_uart_tx_wakeup(). There is a chance, that hci_uart_register_device()
thread won't be fast enough to call percpu_init_rwsem().
Fix it my moving percpu_init_rwsem() call before p->open().
INFO: trying to register non-static key.
The code is fine but needs lockdep annotation, or maybe
you didn't initialize this object before use?
turning off the locking correctness validator.
CPU: 2 PID: 18524 Comm: syz-executor.5 Not tainted 5.16.0-rc6 #9
...
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
assign_lock_key kernel/locking/lockdep.c:951 [inline]
register_lock_class+0x148d/0x1950 kernel/locking/lockdep.c:1263
__lock_acquire+0x106/0x57e0 kernel/locking/lockdep.c:4906
lock_acquire kernel/locking/lockdep.c:5637 [inline]
lock_acquire+0x1ab/0x520 kernel/locking/lockdep.c:5602
percpu_down_read_trylock include/linux/percpu-rwsem.h:92 [inline]
hci_uart_tx_wakeup+0x12e/0x490 drivers/bluetooth/hci_ldisc.c:124
h5_timed_event+0x32f/0x6a0 drivers/bluetooth/hci_h5.c:188
call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421
Fixes: d73e17281665 ("Bluetooth: hci_serdev: Init hci_uart proto_lock to avoid oops")
Reported-by: Yiru Xu <xyru1999@xxxxxxxxx>
Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/bluetooth/hci_serdev.c b/drivers/bluetooth/hci_serdev.c
index 3b00d82d36cf..4cda890ce647 100644
--- a/drivers/bluetooth/hci_serdev.c
+++ b/drivers/bluetooth/hci_serdev.c
@@ -305,6 +305,8 @@ int hci_uart_register_device(struct hci_uart *hu,
if (err)
return err;
+ percpu_init_rwsem(&hu->proto_lock);
+
err = p->open(hu);
if (err)
goto err_open;
@@ -327,7 +329,6 @@ int hci_uart_register_device(struct hci_uart *hu,
INIT_WORK(&hu->init_ready, hci_uart_init_work);
INIT_WORK(&hu->write_work, hci_uart_write_work);
- percpu_init_rwsem(&hu->proto_lock);
/* Only when vendor specific setup callback is provided, consider
* the manufacturer information valid. This avoids filling in the
