kevin/linux
1
Fork 0
Code
05eb0f252b
linux/drivers
History
Kay Sievers 05eb0f252b loop: fix deadlock when sysfs and LOOP_CLR_FD race against each other 
LOOP_CLR_FD takes lo->lo_ctl_mutex and tries to remove the loop sysfs
files. Sysfs calls show() and waits for lo->lo_ctl_mutex. LOOP_CLR_FD
waits for show() to finish to remove the sysfs file.

  cat /sys/class/block/loop0/loop/backing_file
    mutex_lock_nested+0x176/0x350
    ? loop_attr_do_show_backing_file+0x2f/0xd0 [loop]
    ? loop_attr_do_show_backing_file+0x2f/0xd0 [loop]
    loop_attr_do_show_backing_file+0x2f/0xd0 [loop]
    dev_attr_show+0x1b/0x60
    ? sysfs_read_file+0x86/0x1a0
    ? __get_free_pages+0x12/0x50
    sysfs_read_file+0xaf/0x1a0

  ioctl(LOOP_CLR_FD):
    wait_for_common+0x12c/0x180
    ? try_to_wake_up+0x2a0/0x2a0
    wait_for_completion+0x18/0x20
    sysfs_deactivate+0x178/0x180
    ? sysfs_addrm_finish+0x43/0x70
    ? sysfs_addrm_start+0x1d/0x20
    sysfs_addrm_finish+0x43/0x70
    sysfs_hash_and_remove+0x85/0xa0
    sysfs_remove_group+0x59/0x100
    loop_clr_fd+0x1dc/0x3f0 [loop]
    lo_ioctl+0x223/0x7a0 [loop]

Instead of taking the lo_ctl_mutex from sysfs code, take the inner
lo->lo_lock, to protect the access to the backing_file data.

Thanks to Tejun for help debugging and finding a solution.

Cc: Milan Broz <mbroz@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-07-31 22:21:35 +02:00
..
accessibility
acpi Merge branch 'drm-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6 2011-07-26 09:21:09 -07:00
amba
ata drivers: use kzalloc/kcalloc instead of 'kmalloc+memset', where possible 2011-07-25 20:57:13 -07:00
atm atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
auxdisplay
base atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
bcma Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2011-07-25 13:56:39 -07:00
block loop: fix deadlock when sysfs and LOOP_CLR_FD race against each other 2011-07-31 22:21:35 +02:00
bluetooth Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next-2.6 into for-davem 2011-07-15 10:05:24 -04:00
cdrom
char ramoops: fix compile failure on parisc 2011-07-29 23:41:09 -07:00
clk ARM: Consolidate the clkdev header files 2011-07-19 18:09:45 +02:00
clocksource Merge branch 'timers-clocksource-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-07-23 10:34:47 -07:00
connector atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
cpufreq Merge branch 'drm-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6 2011-07-26 09:21:09 -07:00
cpuidle
crypto n2_crypto: Attach on Niagara-T3. 2011-07-28 01:30:07 -07:00
dca
dio
dma dmaengine: imx-sdma: add device tree probe support 2011-07-27 09:31:56 +08:00
edac atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
eisa eisa/pci_eisa.c: fix section mismatch 2011-07-25 20:57:14 -07:00
firewire atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
firmware Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6 2011-07-25 23:06:24 -07:00
gpio Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2011-07-25 13:56:39 -07:00
gpu atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
hid Merge branches 'roccat', 'upstream' and 'wiimote' into for-linus 2011-07-22 22:47:08 +02:00
hwmon Merge branch 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/staging 2011-07-30 08:57:57 -10:00
hwspinlock
i2c i2c-eg20t : Fix the issue of Combined R/W transfer mode 2011-07-27 00:02:28 +01:00
ide Merge branch 'master' into for-next 2011-07-11 14:15:55 +02:00
idle
ieee802154
infiniband Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2011-07-27 13:21:40 -07:00
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2011-07-27 09:24:56 -07:00
iommu
isdn Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2011-07-28 05:58:19 -07:00
leds arch/arm/mach-ux500/board-u5500.c: calibrate ALS input voltage 2011-07-25 20:57:15 -07:00
lguest lguest: Fix in/out emulation 2011-07-22 14:39:51 +09:30
macintosh drivers: fix up various ->llseek() implementations 2011-07-20 20:47:58 -04:00
mca
md Merge branch 'for-linus' of git://neil.brown.name/md 2011-07-28 05:50:27 -07:00
media Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6 2011-07-30 00:08:53 -07:00
memstick
message Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6 2011-07-30 08:36:02 -10:00
mfd Merge git://git.infradead.org/battery-2.6 2011-07-31 06:24:50 -10:00
misc atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
mmc mmc: sdhci-esdhc-imx: add device tree probe support 2011-07-27 09:31:39 +08:00
mtd Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2011-07-25 13:56:39 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-2.6 2011-07-31 06:23:08 -10:00
nfc NFC: pn533: use after free in pn533_disconnect() 2011-07-26 16:27:24 -04:00
nubus
of net: ibm_newemac: convert it to use of_get_phy_mode 2011-07-27 09:31:02 +08:00
oprofile atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
parisc
parport Merge branch 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6 2011-07-25 23:09:27 -07:00
pci Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6 2011-07-29 23:35:05 -07:00
pcmcia Merge git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-2.6 2011-07-31 06:23:08 -10:00
platform asus-wmi: ->is_visible() can't return negative 2011-07-24 10:12:19 -04:00
pnp Merge 'akpm' patch series 2011-07-25 21:00:19 -07:00
power Merge git://git.infradead.org/battery-2.6 2011-07-31 06:24:50 -10:00
pps
ps3
ptp
rapidio
regulator regulator: Convert tps65023 to use regmap API 2011-07-23 07:57:02 +01:00
rtc rtc: fix hrtimer deadlock 2011-07-26 16:49:42 -07:00
s390 atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
sbus atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
scsi Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6 2011-07-30 08:36:02 -10:00
sfi
sh switch assorted clock drivers to debugfs_remove_recursive() 2011-07-20 20:47:51 -04:00
sn
spi Merge branch 'spi/next' of git://git.secretlab.ca/git/linux-2.6 2011-07-22 14:52:44 -07:00
ssb Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2011-07-25 13:56:39 -07:00
staging Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6 2011-07-30 00:08:53 -07:00
target Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2011-07-27 13:21:40 -07:00
tc
telephony
thermal
tty serial/imx: add device tree probe support 2011-07-27 09:30:43 +08:00
uio Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6 2011-07-25 23:06:24 -07:00
usb Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6 2011-07-30 00:08:53 -07:00
uwb uwb: Fix misspelling of neighbourhood in comment 2011-07-21 14:03:41 +02:00
vhost atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
video atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
virt drivers/virt: add missing linux/interrupt.h to fsl_hypervisor.c 2011-07-22 09:24:39 -05:00
virtio virtio: expose for non-virtualization users too 2011-07-23 16:20:30 +09:30
vlynq
w1 atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
watchdog Merge git://git.kernel.org/pub/scm/linux/kernel/git/wim/linux-watchdog 2011-07-29 23:28:47 -07:00
xen Merge branch 'stable/bug.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen 2011-07-29 23:43:32 -07:00
zorro
Kconfig Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc 2011-07-25 22:59:39 -07:00
Makefile Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc 2011-07-25 22:59:39 -07:00