Hans Verkuil e752577ed7 [media] v4l2-mem2mem: drop lock in v4l2_m2m_fop_mmap ... The v4l2_m2m_fop_mmap function takes the core mutex, but this will result in a potential circular locking dependency: [ 262.517164] ====================================================== [ 262.517166] [ INFO: possible circular locking dependency detected ] [ 262.517169] 4.2.0-rc2-koryphon #844 Not tainted [ 262.517171] ------------------------------------------------------- [ 262.517173] v4l2-compliance/1379 is trying to acquire lock: [ 262.517175] (&dev->dev_mutex){+.+.+.}, at: [<ffffffffa000ddab>] v4l2_m2m_fop_mmap+0x2b/0x90 [v4l2_mem2mem] [ 262.517187] but task is already holding lock: [ 262.517189] (&mm->mmap_sem){++++++}, at: [<ffffffff81159309>] vm_mmap_pgoff+0x69/0xc0 [ 262.517199] which lock already depends on the new lock. [ 262.517202] the existing dependency chain (in reverse order) is: [ 262.517204] -> #1 (&mm->mmap_sem){++++++}: [ 262.517209] [<ffffffff810d0e6b>] __lock_acquire+0x62b/0xe80 [ 262.517215] [<ffffffff810d2095>] lock_acquire+0x65/0x90 [ 262.517218] [<ffffffff811612e5>] __might_fault+0x75/0xa0 [ 262.517222] [<ffffffffa06dead9>] video_usercopy+0x3e9/0x4e0 [videodev] [ 262.517231] [<ffffffffa06debe0>] video_ioctl2+0x10/0x20 [videodev] [ 262.517238] [<ffffffffa06d8663>] v4l2_ioctl+0xc3/0xe0 [videodev] [ 262.517243] [<ffffffff811a8cac>] do_vfs_ioctl+0x2fc/0x550 [ 262.517248] [<ffffffff811a8f74>] SyS_ioctl+0x74/0x80 [ 262.517252] [<ffffffff81a4d2ee>] entry_SYSCALL_64_fastpath+0x12/0x76 [ 262.517258] -> #0 (&dev->dev_mutex){+.+.+.}: [ 262.517262] [<ffffffff810cf464>] validate_chain.isra.38+0xd04/0x1170 [ 262.517266] [<ffffffff810d0e6b>] __lock_acquire+0x62b/0xe80 [ 262.517270] [<ffffffff810d2095>] lock_acquire+0x65/0x90 [ 262.517273] [<ffffffff81a48e3c>] mutex_lock_interruptible_nested+0x6c/0x4b0 [ 262.517279] [<ffffffffa000ddab>] v4l2_m2m_fop_mmap+0x2b/0x90 [v4l2_mem2mem] [ 262.517284] [<ffffffffa06d80ff>] v4l2_mmap+0x4f/0x90 [videodev] [ 262.517288] [<ffffffff8116b06c>] mmap_region+0x38c/0x5b0 [ 262.517293] [<ffffffff8116b585>] do_mmap_pgoff+0x2f5/0x3e0 [ 262.517297] [<ffffffff8115932a>] vm_mmap_pgoff+0x8a/0xc0 [ 262.517300] [<ffffffff81169bab>] SyS_mmap_pgoff+0x1cb/0x270 [ 262.517304] [<ffffffff8100876d>] SyS_mmap+0x1d/0x20 [ 262.517309] [<ffffffff81a4d2ee>] entry_SYSCALL_64_fastpath+0x12/0x76 [ 262.517313] other info that might help us debug this: [ 262.517315] Possible unsafe locking scenario: [ 262.517318] CPU0 CPU1 [ 262.517319] ---- ---- [ 262.517321] lock(&mm->mmap_sem); [ 262.517324] lock(&dev->dev_mutex); [ 262.517327] lock(&mm->mmap_sem); [ 262.517329] lock(&dev->dev_mutex); [ 262.517332] *** DEADLOCK *** Since vb2_fop_mmap doesn't take the lock, neither should v4l2_m2m_fop_mmap. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Tested-by: Mikhail Ulyanov <mikhail.ulyanov@cogentembedded.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>		2015-08-11 06:37:23 -03:00
..
accessibility
acpi	Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/nvdimm	2015-07-11 20:44:31 -07:00
amba
android
ata	ata: ahci_platform: Add ACPI _CLS matching	2015-07-07 01:55:21 +02:00
atm
auxdisplay
base	Fix firmware loader uevent buffer NULL pointer dereference	2015-07-09 11:20:01 -07:00
bcma
block	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2015-07-04 19:36:06 -07:00
bluetooth	Bluetooth: ath3k: Add support of 04ca:300d AR3012 device	2015-06-18 21:00:06 +03:00
bus	ARM: SoC: driver updates for v4.2	2015-06-26 11:54:29 -07:00
cdrom
char	Merge tag 'drm-intel-next-fixes-2015-07-02' of git://anongit.freedesktop.org/drm-intel	2015-07-02 14:36:40 -07:00
clk	A small set of fixes for problems found by smatch in new drivers	2015-07-11 11:08:21 -07:00
clocksource	clocksource/imx: Define clocksource for mx27	2015-07-07 10:44:45 +02:00
connector
cpufreq	MIPS, CPUFREQ: Fix spelling of Institute.	2015-07-07 20:59:42 +02:00
cpuidle	Replace module_platform_driver with builtin_platform driver in non modules.	2015-07-02 10:42:13 -07:00
crypto	crypto: marvell/cesa - another fix up for of_get_named_gen_pool() rename	2015-07-03 11:37:02 -07:00
dca
devfreq
dio
dma	Merge branch 'akpm' (patches from Andrew)	2015-07-01 17:47:51 -07:00
dma-buf
edac	A build fix for octeon_edac from Aaro Koskinen.	2015-07-03 12:10:12 -07:00
eisa
extcon
firewire
firmware	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2015-07-03 15:20:57 -07:00
fmc
gpio	Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-07-01 15:19:35 -07:00
gpu	Revert "drm/i915: Use crtc_state->active in primary check_plane func"	2015-07-12 15:00:20 -07:00
hid	Merge branches 'for-4.2/i2c-hid', 'for-4.2/lenovo', 'for-4.2/plantronics', 'for-4.2/rmi', 'for-4.2/sensor-hub', 'for-4.2/sjoy', 'for-4.2/sony' and 'for-4.2/wacom' into for-linus	2015-06-22 16:23:43 +02:00
hsi	Fix up implicit <module.h> users that will break later.	2015-07-02 10:25:22 -07:00
hv
hwmon	hwmon: (w83627ehf) Use swap() in w82627ehf_swap_tempreg()	2015-07-03 14:39:06 +02:00
hwspinlock	hwspinlock: qcom: Correct msb in regmap_field	2015-07-01 16:15:05 +03:00
hwtracing/coresight
i2c	i2c: Mark instantiated device nodes with OF_POPULATE	2015-07-09 22:25:54 +02:00
ide	Minor merge needed, due to function move.	2015-07-01 10:49:25 -07:00
idle
iio
infiniband	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2015-07-04 19:36:06 -07:00
input	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input	2015-07-11 11:16:04 -07:00
iommu	IOMMU Fixes for Linux v4.2-rc0	2015-07-01 14:44:22 -07:00
ipack
irqchip	Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus	2015-07-12 13:55:24 -07:00
isdn	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2015-06-24 16:49:49 -07:00
leds	Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/linux-leds	2015-07-01 19:09:11 -07:00
lguest	Merge branch 'x86-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-06-22 17:59:09 -07:00
macintosh	macintosh/nvram: Remove as unused	2015-06-15 16:42:37 +10:00
mailbox	Replace module_init with appropriate alternate initcall in non modules.	2015-07-02 10:36:29 -07:00
mcb
md	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2015-07-04 19:36:06 -07:00
media	[media] v4l2-mem2mem: drop lock in v4l2_m2m_fop_mmap	2015-08-11 06:37:23 -03:00
memory	Merge branch 'fixes-rc1' into omap-for-v4.2/fixes	2015-07-06 05:33:17 -07:00
memstick	memstick: remove deprecated use of pci api	2015-06-30 19:44:57 -07:00
message	fusion: remove dead MTRR code	2015-06-13 08:44:14 -07:00
mfd	Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-07-01 15:19:35 -07:00
misc	powerpc fixes for 4.2	2015-07-10 12:16:59 -07:00
mmc	ARM: SoC: late fixes and dependencies	2015-07-02 14:40:49 -07:00
mtd	Minor merge needed, due to function move.	2015-07-01 10:49:25 -07:00
net	A very significant modification to NTB in this series.	2015-07-04 14:07:47 -07:00
nfc	Char/Misc driver patches for 4.2-rc1	2015-06-26 14:51:15 -07:00
ntb	NTB: Add split BAR output for debugfs stats	2015-07-04 14:09:32 -04:00
nubus
nvdimm	nvdimm: Fix return value of nvdimm_bus_init() if class_create() fails	2015-06-30 14:30:34 -04:00
of	Devicetree changes for v4.2	2015-07-01 19:40:18 -07:00
oprofile
parisc
parport
pci	Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-07-01 15:19:35 -07:00
pcmcia	Fix up implicit <module.h> users that will break later.	2015-07-02 10:25:22 -07:00
phy	Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus	2015-06-27 12:44:34 -07:00
pinctrl	Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-07-01 15:19:35 -07:00
platform	platform-drivers-x86 for 4.2-2	2015-07-05 10:54:09 -07:00
pnp	ACPI / PNP: Reserve ACPI resources at the fs_initcall_sync stage	2015-07-06 23:52:21 +02:00
power	Replace module_platform_driver with builtin_platform driver in non modules.	2015-07-02 10:42:13 -07:00
powercap
pps
ps3
ptp
pwm	pwm: Changes for v4.2-rc1	2015-06-23 13:32:38 -07:00
rapidio	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2015-06-23 14:08:54 -07:00
ras
regulator	Fix up implicit <module.h> users that will break later.	2015-07-02 10:25:22 -07:00
remoteproc	remoteproc: fix !CONFIG_OF build breakage	2015-06-18 11:44:41 +03:00
reset
rpmsg
rtc	Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus	2015-06-27 12:44:34 -07:00
s390	KVM: s390: virtio-ccw: don't overwrite config space values	2015-07-03 18:55:18 +02:00
sbus
scsi	Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending	2015-07-04 14:13:43 -07:00
sfi
sh	Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-07-01 15:19:35 -07:00
sn
soc	ARM: SoC: late fixes and dependencies	2015-07-02 14:40:49 -07:00
spi	Merge remote-tracking branches 'spi/topic/sirf', 'spi/topic/spidev' and 'spi/topic/zynq' into spi-next	2015-06-18 00:19:56 +01:00
spmi
ssb
staging	[media] staging: media: lirc: fix coding style error	2015-07-22 13:27:40 -03:00
target	Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending	2015-07-04 14:13:43 -07:00
tc
thermal	Minor merge needed, due to function move.	2015-07-01 10:49:25 -07:00
thunderbolt
tty	ARM: SoC: late fixes and dependencies	2015-07-02 14:40:49 -07:00
uio
usb	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2015-07-04 19:36:06 -07:00
uwb
vfio	VFIO updates for v4.2	2015-06-28 12:32:13 -07:00
vhost	Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending	2015-07-04 14:13:43 -07:00
video	stifb: Implement hardware accelerated copyarea	2015-07-10 21:44:19 +02:00
virt
virtio	virtio/vhost: cross endian support	2015-07-03 16:02:25 -07:00
vlynq
vme	vme: tsi148: depend on HAS_DMA for Kconfig	2015-06-12 17:31:05 -07:00
w1
watchdog	Merge git://www.linux-watchdog.org/linux-watchdog	2015-07-01 19:33:16 -07:00
xen	Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending	2015-07-04 14:13:43 -07:00
zorro
Kconfig	libnvdimm, nfit: initial libnvdimm infrastructure and NFIT support	2015-06-24 21:24:10 -04:00
Makefile	The libnvdimm sub-system introduces, in addition to the libnvdimm-core,	2015-06-29 10:34:42 -07:00