From: Greg KH <gregkh@linuxfoundation.org>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Sam Sun <samsun1006219@gmail.com>, Tejun Heo <tj@kernel.org>,
linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
"xrivendell7@gmail.com" <xrivendell7@gmail.com>,
hgajjar@de.adit-jv.com, quic_ugoswami@quicinc.com,
stanley_chang@realtek.com, heikki.krogerus@linux.intel.com
Subject: Re: [Bug] INFO: task hung in hub_activate
Date: Mon, 4 Mar 2024 17:36:19 +0100 [thread overview]
Message-ID: <2024030428-graph-harmful-1597@gregkh> (raw)
In-Reply-To: <e9d710fc-eace-44de-b3cc-1117c3575ef7@rowland.harvard.edu>
On Mon, Mar 04, 2024 at 11:15:24AM -0500, Alan Stern wrote:
> Third, this must be a generic problem. It will occur any time a sysfs
> attribute callback tries to lock its device while another process is
> trying to unregister that device.
>
> We faced this sort of problem some years ago when we were worrying
> about "suicidal" attributes -- ones which would unregister their own
> devices. I don't remember what the fix was or how it worked. But we
> need something like it here.
>
> Greg and Tejun, any ideas? Is it possible somehow for an attribute file
> to be removed while its callback is still running?
Yes, it's a pain, and I hate it, but I think SCSI does this somehow for
one of their attributes. I don't remember how at the moment, and I
can't look it up (am traveling), but this should be a good hint.
thanks,
greg k-h
next prev parent reply other threads:[~2024-03-04 16:36 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-04 12:10 [Bug] INFO: task hung in hub_activate Sam Sun
2024-03-04 13:37 ` Hillf Danton
2024-03-04 14:59 ` Alan Stern
2024-03-04 16:15 ` Alan Stern
2024-03-04 16:36 ` Greg KH [this message]
2024-03-04 18:30 ` Alan Stern
2024-03-04 19:17 ` Bug in sysfs_break_active_protection() Alan Stern
2024-03-13 20:21 ` Tejun Heo
2024-03-13 21:43 ` [PATCH] fs: sysfs: Fix reference leak " Alan Stern
2024-03-13 21:44 ` Tejun Heo
2024-03-13 22:10 ` Bart Van Assche
2024-03-05 12:03 ` [Bug] INFO: task hung in hub_activate Greg KH
2024-03-07 20:35 ` Alan Stern
2024-03-08 2:48 ` Sam Sun
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