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a9dc960c37
A number of tx queue wake-up events went missing due to the outlined scenario below. Start state is a pool of 16 tx URBs, active tx_urbs count = 15, with the netdev tx queue open. CPU #1 [softirq] CPU #2 [softirq] start_xmit() tx_acknowledge() ................ ................ atomic_inc(&tx_urbs); if (atomic_read(&tx_urbs) >= 16) { --> atomic_dec(&tx_urbs); netif_wake_queue(); return; <-- netif_stop_queue(); } At the end, the correct state expected is a 15 tx_urbs count value with the tx queue state _open_. Due to the race, we get the same tx_urbs value but with the tx queue state _stopped_. The wake-up event is completely lost. Thus avoid hand-rolled concurrency mechanisms and use a proper lock for contexts and tx queue protection. Signed-off-by: Ahmed S. Darwish <ahmed.darwish@valeo.com> Cc: linux-stable <stable@vger.kernel.org> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> |
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appletalk | ||
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bonding | ||
caif | ||
can | ||
cris | ||
dsa | ||
ethernet | ||
fddi | ||
hamradio | ||
hippi | ||
hyperv | ||
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ipvlan | ||
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phy | ||
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team | ||
usb | ||
vmxnet3 | ||
wan | ||
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wireless | ||
xen-netback | ||
dummy.c | ||
eql.c | ||
ifb.c | ||
Kconfig | ||
LICENSE.SRC | ||
loopback.c | ||
macvlan.c | ||
macvtap.c | ||
Makefile | ||
mdio.c | ||
mii.c | ||
netconsole.c | ||
nlmon.c | ||
ntb_netdev.c | ||
rionet.c | ||
sb1000.c | ||
Space.c | ||
sungem_phy.c | ||
tun.c | ||
veth.c | ||
virtio_net.c | ||
vxlan.c | ||
xen-netfront.c |