From: Oliver Neukum <oneukum@suse.com>
To: Benjamin Berg <bberg@redhat.com>,
Oliver Neukum <oneukum@suse.com>,
syzbot <syzbot+485cc00ea7cf41dfdbf1@syzkaller.appspotmail.com>,
Thinh.Nguyen@synopsys.com, changbin.du@intel.com,
christian.brauner@ubuntu.com, davem@davemloft.net,
edumazet@google.com, gregkh@linuxfoundation.org,
johan.hedberg@gmail.com, kuba@kernel.org,
linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-usb@vger.kernel.org, luiz.dentz@gmail.com,
luiz.von.dentz@intel.com, marcel@holtmann.org,
mathias.nyman@linux.intel.com, netdev@vger.kernel.org,
stern@rowland.harvard.edu, syzkaller-bugs@googlegroups.com,
yajun.deng@linux.dev
Subject: Re: [syzbot] BUG: sleeping function called from invalid context in hci_cmd_sync_cancel
Date: Thu, 9 Dec 2021 14:21:20 +0100 [thread overview]
Message-ID: <f47f6972-b977-aae8-dd4d-44d85db2e8a4@suse.com> (raw)
In-Reply-To: <14584c1a1e449cc20b5af7918b411ee27cf1570b.camel@redhat.com>
On 09.12.21 13:46, Benjamin Berg wrote:
Hi,
> On Thu, 2021-12-09 at 11:06 +0100, Oliver Neukum wrote:
>> 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.
>
>> 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
prev parent reply other threads:[~2021-12-09 13:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-08 20:36 [syzbot] BUG: sleeping function called from invalid context in hci_cmd_sync_cancel syzbot
2021-12-09 1:59 ` syzbot
2021-12-09 10:06 ` Oliver Neukum
2021-12-09 12:46 ` Benjamin Berg
2021-12-09 13:21 ` Oliver Neukum [this message]
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