Re: [syzbot] BUG: sleeping function called from invalid context in hci_cmd_sync_cancel

On 09.12.21 13:46, Benjamin Berg wrote:
Hi,

On Thu, 2021-12-09 at 11:06 +0100, Oliver Neukum wrote:

quoted

As __cancel_work_timer can be called from hci_cmd_sync_cancel() this is
just not
an approach you can take. It looks like asynchronously canceling the
scheduled work
would result in a race, so I would for now just revert.

Right, so this needs to be pushed into a workqueue instead, I suppose.

It looks like overkill, but I have no good alternative to offer either.

quoted

What issue exactly is this trying to fix or improve?

The problem is aborting long-running synchronous operations. i.e.
without this patchset, USB enumeration will hang for 10s if a USB
bluetooth device disappears during firmware loading. This is because
even though the USB device is gone and all URB submissions fail, the
operation will only be aborted after the internal timeout happens.

I see. Something ought to be done. The issue is in good hands.

    Thanks
        Oliver