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51311d0a5c
linux-next/drivers
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Chris Wilson 51311d0a5c drm/i915: Do not hold mutex when faulting in user addresses 
Linus Torvalds found that it was rather trivial to trigger a system
freeze:

  In fact, with lockdep, I don't even need to do the sysrq-d thing: it
  shows the bug as it happens. It's the X server taking the same lock
  recursively.

  Here's the problem:

    =============================================
    [ INFO: possible recursive locking detected ]
    2.6.37-rc2-00012-gbdbd01a #7
    ---------------------------------------------
    Xorg/2816 is trying to acquire lock:
     (&dev->struct_mutex){+.+.+.}, at: [<ffffffff812c626c>] i915_gem_fault+0x50/0x17e

    but task is already holding lock:
     (&dev->struct_mutex){+.+.+.}, at: [<ffffffff812c403b>] i915_mutex_lock_interruptible+0x28/0x4a

    other info that might help us debug this:
    2 locks held by Xorg/2816:
     #0:  (&dev->struct_mutex){+.+.+.}, at: [<ffffffff812c403b>] i915_mutex_lock_interruptible+0x28/0x4a
     #1:  (&mm->mmap_sem){++++++}, at: [<ffffffff81022d4f>] page_fault+0x156/0x37b

This recursion was introduced by rearranging the locking to avoid the
double locking on the fast path (4f27b5d and fbd5a26d) and the
introduction of the prefault to encourage the fast paths (b5e4f2b). In
order to undo the problem, we rearrange the code to perform the access
validation upfront, attempt to prefault and then fight for control of the
mutex.  the best case scenario where the mutex is uncontended the
prefaulting is not wasted.

Reported-and-tested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
2010-11-19 09:30:15 +00:00
..
accessibility
acpi ACPI: debugfs custom_method open to non-root 2010-11-13 09:52:16 -08:00
amba
ata drivers/ata/pata_octeon_cf.c: delete double assignment 2010-11-12 17:10:55 -05:00
atm solos: Refuse to upgrade firmware with older FPGA. It doesn't work. 2010-11-08 12:17:05 -08:00
auxdisplay
base Merge branch 'pm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6 2010-10-29 15:09:56 -07:00
block Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block 2010-11-12 08:52:47 -08:00
bluetooth Bluetooth: Add MacBookAir3,1(2) support 2010-11-09 01:08:53 -02:00
cdrom cdrom: gdrom: ctrl_in/outX to __raw_read/writeX conversion. 2010-10-27 14:33:39 +09:00
char Merge branch 'urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-2.6 2010-11-13 10:00:15 -08:00
clocksource ARM: shmobile: remove sh_timer_config clk member 2010-10-31 10:40:39 -04:00
connector connector: remove lazy workqueue creation 2010-10-24 14:20:01 -07:00
cpufreq [CPUFREQ] add sampling_down_factor tunable to improve ondemand performance 2010-10-22 11:44:47 -04:00
cpuidle
crypto Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2010-11-13 09:55:56 -08:00
dca
dio
dma drivers/dma/Kconfig: add part number for Topcliff. 2010-10-29 14:14:02 -07:00
edac Merge branch 'linux_next' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/i7core 2010-10-26 10:13:48 -07:00
eisa
firewire Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6 2010-11-05 14:17:22 -07:00
firmware dmi: log board, system, and BIOS information 2010-10-27 18:03:05 -07:00
gpio gpio: Add VIA VX855 GPIO driver 2010-10-29 00:29:51 +02:00
gpu drm/i915: Do not hold mutex when faulting in user addresses 2010-11-19 09:30:15 +00:00
hid Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2010-10-25 07:59:01 -07:00
hwmon hwmon: (gpio-fan) Fix fan_ctrl_init error path 2010-11-11 09:43:51 -08:00
i2c i2c-i801: Add PCI idents for Patsburg 'IDF' SMBus controllers 2010-10-31 21:07:00 +01:00
ide ide: clean up timed out request handling 2010-10-26 10:17:30 -07:00
idle Merge branch 'idle-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6 2010-10-26 17:28:07 -07:00
ieee802154
infiniband convert get_sb_single() users 2010-10-29 04:16:28 -04:00
input Input: do not pass injected events back to the originating handler 2010-11-11 01:01:26 -08:00
isdn Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6 2010-11-05 15:25:48 -07:00
leds drivers/leds/leds-gpio.c: properly initialize return value 2010-11-12 07:55:32 -08:00
lguest
macintosh drivers/macintosh/adb-iop.c: flags should be unsigned long 2010-11-12 07:55:30 -08:00
mca
md block: read i_size with i_size_read() 2010-11-10 14:40:53 +01:00
media [media] soc-camera: Compile fixes for mx2-camera 2010-11-09 15:16:31 -02:00
memstick
message Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6 2010-10-22 17:34:15 -07:00
mfd mfd: Fix a memory leak when unload mc13xxx-core module 2010-10-29 00:30:43 +02:00
misc drivers/misc/bh1770glc.c: error handling in bh1770_power_state_store() 2010-11-12 07:55:31 -08:00
mmc mfd: Adding twl6030 mmc card detect support for MMC1 2010-10-29 00:29:59 +02:00
mtd Merge git://git.infradead.org/mtd-2.6 2010-10-30 08:31:35 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6 2010-11-12 17:17:55 -08:00
nubus
of of/mips: Cleanup some include directives/files. 2010-10-21 11:10:11 -06:00
oprofile Merge branches 'perf-fixes-for-linus' and 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-30 11:43:26 -07:00
parisc Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/kyle/parisc-2.6 2010-10-28 09:24:14 -07:00
parport Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2010-10-24 13:41:39 -07:00
pci xen-pcifront: fix PCI reference leak 2010-11-08 11:41:15 -05:00
pcmcia drivers/pcmcia/soc_common.c: Use printf extension %pV 2010-11-10 14:31:28 +01:00
platform Remove duplicate includes from many files 2010-10-27 18:03:18 -07:00
pnp Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6 2010-10-26 17:28:37 -07:00
power power: Revert "power_supply: Mark twl4030_charger as broken" 2010-10-29 00:30:44 +02:00
pps
ps3
rapidio rapidio: use resource_size() 2010-11-12 07:55:30 -08:00
regulator regulator: max8998 BUCK1/2 voltage change with use of GPIOs 2010-10-29 00:30:15 +02:00
rtc sh: mach-snapgear: Kill off machtype, consolidate board def. 2010-10-29 19:06:53 +09:00
s390 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6 2010-11-12 17:17:55 -08:00
sbus Merge branch 'next-devicetree' of git://git.secretlab.ca/git/linux-2.6 2010-10-25 08:19:14 -07:00
scsi block: remove REQ_HARDBARRIER 2010-11-10 14:54:09 +01:00
serial Revert "8250: Fix tcsetattr to avoid ioctl(TIOCMIWAIT) hang" 2010-11-13 09:59:19 -08:00
sfi
sh Merge branches 'sh/pio-death', 'sh/nommu', 'sh/clkfwk', 'sh/core' and 'sh/intc-extension' into sh-fixes-for-linus 2010-11-08 09:42:43 +09:00
sn
spi Merge branch 'next-spi' of git://git.secretlab.ca/git/linux-2.6 2010-11-01 07:50:43 -04:00
ssb
staging Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6 2010-11-13 09:55:19 -08:00
tc
telephony Merge branch 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl 2010-10-22 10:52:56 -07:00
thermal
tty n_gsm: Fix length handling 2010-11-11 11:06:09 -08:00
uio Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2010-10-24 13:41:39 -07:00
usb Merge branch 'usb-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6 2010-11-12 17:13:28 -08:00
uwb UWB: Return UWB_RSV_ALLOC_NOT_FOUND rather than crashing on NULL dereference if kzalloc fails 2010-11-11 07:14:07 -08:00
vhost Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6 2010-10-23 11:47:02 -07:00
video backlight: MacBookAir3,1(3,2) mbp-nvidia-bl support 2010-11-12 07:55:33 -08:00
virtio
vlynq
w1 w1: don't allow arbitrary users to remove w1 devices 2010-10-27 18:03:17 -07:00
watchdog WATCHDOG: octeon-wdt: Use I/O clock rate for timing calculations. 2010-10-29 19:08:42 +01:00
xen Merge branch 'upstream/core' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen 2010-11-12 16:01:55 -08:00
zorro zorro: Fix device_register() error handling 2010-10-22 09:43:25 +02:00
Kconfig
Makefile TTY: create drivers/tty and move the tty core files there 2010-11-05 08:10:33 -07:00