From: Florian Fainelli <f.fainelli@gmail.com>
To: Andrew Lunn <andrew@lunn.ch>, davem@davemloft.net, linux@roeck-us.net
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH net-next 10/10] net: dsa: Add lockdep class to tx queues to avoid lockdep splat
Date: Tue, 05 May 2015 16:22:33 -0700 [thread overview]
Message-ID: <554950B9.4020807@gmail.com> (raw)
In-Reply-To: <1430867396-2268-11-git-send-email-andrew@lunn.ch>
On 05/05/15 16:09, Andrew Lunn wrote:
> DSA stacks an Ethernet device on top of an Ethernet device. This can
> cause false positive lockdep splats for the transmit queue:
>
> =============================================
> [ INFO: possible recursive locking detected ]
> 4.0.0-rc7-01838-g70621a215fc7 #386 Not tainted
> ---------------------------------------------
> kworker/0:0/4 is trying to acquire lock:
> (_xmit_ETHER#2){+.-...}, at: [<c040e95c>] sch_direct_xmit+0xa8/0x1fc
>
> but task is already holding lock:
> (_xmit_ETHER#2){+.-...}, at: [<c03f4208>] __dev_queue_xmit+0x4d4/0x56c
>
> other info that might help us debug this:
> Possible unsafe locking scenario:
>
> CPU0
> ----
> lock(_xmit_ETHER#2);
> lock(_xmit_ETHER#2);
>
> To avoid this, walk the tq queues of the dsa slaves and set a lockdep
> class.
Had meant to fix that a while ago when this was bugging me, thanks for
doing this!
>
> Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
--
Florian
next prev parent reply other threads:[~2015-05-05 23:22 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-05 23:09 [PATCH net-next 00/10] More Marvell DSA refactring and fixup Andrew Lunn
2015-05-05 23:09 ` [PATCH net-next 01/10] net: dsa: Centralise global and port setup code into mv88e6xxx Andrew Lunn
2015-05-05 23:09 ` [PATCH net-next 02/10] net: dsa: Centralize setting up ports Andrew Lunn
2015-05-05 23:09 ` [PATCH net-next 03/10] net: dsa: Converting remaining registers to mnemonics Andrew Lunn
2015-05-05 23:09 ` [PATCH net-next 04/10] net: dsa: Move mv88e6172 support into mv88e6352 family driver Andrew Lunn
2015-05-05 23:09 ` [PATCH net-next 05/10] net: dsa: mv88e6171: Add other members of the family Andrew Lunn
2015-05-05 23:09 ` [PATCH net-next 06/10] net: dsa: mv88e6131: Add support for mv88e6185 Andrew Lunn
2015-05-05 23:09 ` [PATCH net-next 07/10] net: dsa: mv88e6xxx: Replace PHY mutex by SMI mutex Andrew Lunn
2015-05-05 23:09 ` [PATCH net-next 08/10] net: dsa: mv88e6xxx: Replace stats mutex with " Andrew Lunn
2015-05-05 23:09 ` [PATCH net-next 09/10] net: dsa: mv88e6xxx: Fix false positive lockdep splat Andrew Lunn
2015-05-05 23:09 ` [PATCH net-next 10/10] net: dsa: Add lockdep class to tx queues to avoid " Andrew Lunn
2015-05-05 23:22 ` Florian Fainelli [this message]
2015-05-09 20:07 ` [PATCH net-next 00/10] More Marvell DSA refactring and fixup David Miller
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