net: moxa: fix TX overrun memory leak

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[ Upstream commit c2b341a620 ]

moxart_mac_start_xmit() doesn't care where tx_tail is, tx_head can
catch and pass tx_tail, which is bad because moxart_tx_finished()
isn't guaranteed to catch up on freeing resources from tx_tail.

Add a check in moxart_mac_start_xmit() stopping the queue at the
end of the circular buffer. Also add a check in moxart_tx_finished()
waking the queue if the buffer has TX_WAKE_THRESHOLD or more
free descriptors.

While we're at it, move spin_lock_irq() to happen before our
descriptor pointer is assigned in moxart_mac_start_xmit().

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=99451

Signed-off-by: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Jonas Jensen 2017-03-28 12:12:38 +02:00 • committed by Greg Kroah-Hartman

parent ce19146a0d

commit 55b6a5d080

2 changed files with 19 additions and 2 deletions

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20

drivers/net/ethernet/moxa/moxart_ether.c

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1

drivers/net/ethernet/moxa/moxart_ether.h

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