bug: mutex_lock() in interrupt conntext via phy_stop() in gianfar

[Sebastian Siewior]

* Benjamin Herrenschmidt | 2008-07-24 08:12:48 [+1000]:

>On Mon, 2008-07-21 at 17:57 -0500, Nate Case wrote:
>> On Fri, 2008-07-18 at 14:10 +0200, Sebastian Siewior wrote:
>> > Commit 35b5f6b1a aka [PHYLIB: Locking fixes for PHY I/O potentially sleeping]
>> > changed the phydev->lock from spinlock into a mutex. Now, the following
>> > code path got triggered while NFS was unavailable:
>> > 
>> [snip]
>> > |[  194.864733] BUG: sleeping function called from invalid context at /home/bigeasy/git/linux-2.6-powerpc/kernel/mutex.c:87
>> > |[  194.875529] in_atomic():1, irqs_disabled():0
>> > |[  194.879805] Call Trace:
>> > |[  194.882250] [c0383d90] [c0006dd8] show_stack+0x48/0x184 (unreliable)
>> > |[  194.888649] [c0383db0] [c001e938] __might_sleep+0xe0/0xf4
>> > |[  194.894069] [c0383dc0] [c025a43c] mutex_lock+0x24/0x3c
>> > |[  194.899234] [c0383de0] [c019005c] phy_stop+0x20/0x70
>> > |[  194.904234] [c0383df0] [c018d4ec] stop_gfar+0x28/0xf4
>> > |[  194.909305] [c0383e10] [c018e8c4] gfar_timeout+0x30/0x60
>> > |[  194.914638] [c0383e20] [c01fe7c0] dev_watchdog+0xa8/0x144
>> 
>> Hmm..  I'm not sure what the best solution is to this.  Make the
>> stop_gfar() call happen in a workqueue, and make a similar change to
>> ucc_geth, fec_mpc52xx, and fs_enet? Modify phy_stop() to do the work in
>> a workqueue conditionally if in interrupt context?  Between these two
>> I'd lean toward the latter.
>> 
>> Does anyone have any better ideas?
>
>Move the reset task to a workqueue.
Done in [1] Ben.

[1] http://marc.info/?l=linux-netdev&m=121684347609062&w=2
>Cheers,
>Ben.

Sebastian