linux/drivers
David Vrabel 900e183301 xen-netfront: use different locks for Rx and Tx stats
In netfront the Rx and Tx path are independent and use different
locks.  The Tx lock is held with hard irqs disabled, but Rx lock is
held with only BH disabled.  Since both sides use the same stats lock,
a deadlock may occur.

  [ INFO: possible irq lock inversion dependency detected ]
  3.16.2 #16 Not tainted
  ---------------------------------------------------------
  swapper/0/0 just changed the state of lock:
   (&(&queue->tx_lock)->rlock){-.....}, at: [<c03adec8>]
  xennet_tx_interrupt+0x14/0x34
  but this lock took another, HARDIRQ-unsafe lock in the past:
   (&stat->syncp.seq#2){+.-...}
  and interrupts could create inverse lock ordering between them.
  other info that might help us debug this:
   Possible interrupt unsafe locking scenario:

         CPU0                    CPU1
         ----                    ----
    lock(&stat->syncp.seq#2);
                                 local_irq_disable();
                                 lock(&(&queue->tx_lock)->rlock);
                                 lock(&stat->syncp.seq#2);
    <Interrupt>
      lock(&(&queue->tx_lock)->rlock);

Using separate locks for the Rx and Tx stats fixes this deadlock.

Reported-by: Dmitry Piotrovsky <piotrovskydmitry@gmail.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-01-13 17:22:11 -05:00
..
accessibility
acpi Merge branch 'acpi-video' 2014-12-29 21:24:13 +01:00
amba Char/Misc driver patches for 3.19-rc1 2014-12-14 16:43:47 -08:00
android
ata More ACPI and power management updates for 3.19-rc1 2014-12-18 20:28:33 -08:00
atm Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
auxdisplay
base Merge branches 'pm-domains', 'powercap' and 'pm-tools' 2014-12-29 21:24:00 +01:00
bcma Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2014-12-11 17:56:37 -08:00
block Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client 2014-12-17 16:03:12 -08:00
bluetooth Merge branch 'for-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next 2014-12-15 13:23:09 -05:00
bus Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
cdrom
char ipmi: Fix compile warning with tv_usec 2014-12-30 13:34:36 -06:00
clk Please consider pulling the clk framework changes toward 3.19. It is 2014-12-20 16:42:36 -08:00
clocksource Fixes for 3.19 2014-12-30 15:27:20 +01:00
connector
coresight
cpufreq Merge branches 'pm-cpufreq' and 'pm-cpuidle' 2014-12-29 21:23:41 +01:00
cpuidle Merge branches 'pm-cpufreq' and 'pm-cpuidle' 2014-12-29 21:23:41 +01:00
crypto Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
dca
devfreq
dio
dma Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
dma-buf
edac Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
eisa
extcon Char/Misc driver patches for 3.19-rc1 2014-12-14 16:43:47 -08:00
firewire firewire: sbp2: replace card lock by target lock 2014-12-10 20:53:21 +01:00
firmware Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
fmc
gpio Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
gpu Revert "drm/gem: Warn on illegal use of the dumb buffer interface v2" 2014-12-24 13:13:22 +10:00
hid Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid 2014-12-12 10:26:47 -08:00
hsi * misc. fixes in omap-ssi and nokia-modem drivers 2014-12-15 17:33:47 -08:00
hv Char/Misc driver patches for 3.19-rc1 2014-12-14 16:43:47 -08:00
hwmon Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux 2014-12-17 10:16:27 -08:00
hwspinlock
i2c Merge branch 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2014-12-20 13:52:52 -08:00
ide Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
idle
iio Staging patches for 3.19-rc1 2014-12-15 18:06:13 -08:00
infiniband SCSI for-linus on 20141220 2014-12-20 13:42:57 -08:00
input Revert "Input: atmel_mxt_ts - use deep sleep mode when stopped" 2014-12-31 12:59:34 -08:00
iommu Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-12-19 14:02:02 -08:00
ipack
irqchip Merge branch 'irq-irqdomain-arm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-12-15 17:30:09 -08:00
isdn isdn: fix NUL (\0 or \x00) specification in string 2015-01-12 15:31:35 -05:00
leds More ACPI and power management updates for 3.19-rc1 2014-12-18 20:28:33 -08:00
lguest virtio: allow finalize_features to fail 2014-12-09 16:32:32 +02:00
macintosh macintosh: therm_pm72: delete deprecated driver 2014-12-19 19:32:47 +01:00
mailbox Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
mcb
md dm: fix missed error code if .end_io isn't implemented by target_type 2014-12-17 12:31:13 -05:00
media More ACPI and power management updates for 3.19-rc1 2014-12-18 20:28:33 -08:00
memory MTD updates for 3.19: 2014-12-17 09:59:26 -08:00
memstick
message
mfd Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2014-12-30 16:59:59 -08:00
misc powerpc updates for 3.19 batch 2 2014-12-19 12:57:45 -08:00
mmc mmc: core: stop trying to switch width when only one bit is supported 2014-12-29 14:49:28 +01:00
mtd MTD updates for 3.19: 2014-12-17 09:59:26 -08:00
net xen-netfront: use different locks for Rx and Tx stats 2015-01-13 17:22:11 -05:00
nfc More ACPI and power management updates for 3.19-rc1 2014-12-18 20:28:33 -08:00
ntb
nubus
of ARM: SoC/iommu configuration for 3.19 2014-12-16 14:53:01 -08:00
oprofile
parisc
parport Char/Misc driver patches for 3.19-rc1 2014-12-14 16:43:47 -08:00
pci Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-12-19 14:02:02 -08:00
pcmcia Char/Misc driver patches for 3.19-rc1 2014-12-14 16:43:47 -08:00
phy More ACPI and power management updates for 3.19-rc1 2014-12-18 20:28:33 -08:00
pinctrl Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
platform platform-drivers-x86 for 3.19 2014-12-18 20:24:55 -08:00
pnp
power More ACPI and power management updates for 3.19-rc1 2014-12-18 20:28:33 -08:00
powercap powercap / RAPL: add IDs for future Xeon CPUs 2014-12-17 02:35:42 +01:00
pps
ps3
ptp
pwm pwm: Changes for v3.19-rc1 2014-12-17 10:10:51 -08:00
rapidio
ras
regulator regulator: Fix for v3.19 2014-12-29 13:24:38 -08:00
remoteproc Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
reset Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
rpmsg
rtc Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
s390 Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
sbus
scsi SCSI: fix regression in scsi_send_eh_cmnd() 2014-12-30 08:59:13 -08:00
sfi
sh drivers: sh / PM: Replace CONFIG_PM_RUNTIME with CONFIG_PM 2014-12-05 03:08:24 +01:00
sn
soc Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux 2014-12-15 15:52:01 -08:00
spi Merge remote-tracking branches 'spi/fix/img-spfi' and 'spi/fix/msiof' into spi-linus 2014-12-24 12:57:54 +00:00
spmi
ssb Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2014-12-11 17:56:37 -08:00
staging [regression] braino in "lustre: use is_root_inode()" 2014-12-26 22:43:19 -05:00
target SCSI for-linus on 20141220 2014-12-20 13:42:57 -08:00
tc
thermal Merge branches 'thermal-core', 'thermal-soc' and 'thermal-int340x' of .git into next 2014-12-24 10:38:30 +08:00
thunderbolt
tty tty: 8250_omap: Replace CONFIG_PM_RUNTIME with CONFIG_PM 2014-12-19 15:27:58 +01:00
uio Char/Misc driver patches for 3.19-rc1 2014-12-14 16:43:47 -08:00
usb SCSI for-linus on 20141220 2014-12-20 13:42:57 -08:00
uwb
vfio VFIO updates for v3.19-rc1 2014-12-17 10:44:22 -08:00
vhost vhost: relax used address alignment 2014-12-29 10:55:06 +02:00
video OMAPDSS: SDI: fix output port_num 2014-12-30 11:18:30 +02:00
virt
virtio vhost/virtio: virtio 1.0 related fixes 2014-12-18 20:50:30 -08:00
vlynq
vme
w1 Char/Misc driver patches for 3.19-rc1 2014-12-14 16:43:47 -08:00
watchdog watchdog: imx2_wdt: Fix the argument of watchdog_active() 2014-12-18 16:01:20 +01:00
xen Merge remote-tracking branch 'scsi-queue/drivers-for-3.19' into for-linus 2014-12-18 05:56:29 -08:00
zorro
Kconfig Staging patches for 3.19-rc1 2014-12-15 18:06:13 -08:00
Makefile Staging patches for 3.19-rc1 2014-12-15 18:06:13 -08:00