Jiri Kosina 1deb9d341d HID: debug: fix RCU preemption issue ... Commit 2353f2bea ("HID: protect hid_debug_list") introduced mutex locking around debug_list access to prevent SMP races when debugfs nodes are being operated upon by multiple userspace processess. mutex is not a proper synchronization primitive though, as the hid-debug callbacks are being called from atomic contexts. We also have to be careful about disabling IRQs when taking the lock to prevent deadlock against IRQ handlers. Benjamin reports this has also been reported in RH bugzilla as bug #958935. =============================== [ INFO: suspicious RCU usage. ] 3.9.0+ #94 Not tainted ------------------------------- include/linux/rcupdate.h:476 Illegal context switch in RCU read-side critical section! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 0 4 locks held by Xorg/5502: #0: (&evdev->mutex){+.+...}, at: [<ffffffff81512c3d>] evdev_write+0x6d/0x160 #1: (&(&dev->event_lock)->rlock#2){-.-...}, at: [<ffffffff8150dd9b>] input_inject_event+0x5b/0x230 #2: (rcu_read_lock){.+.+..}, at: [<ffffffff8150dd82>] input_inject_event+0x42/0x230 #3: (&(&usbhid->lock)->rlock){-.....}, at: [<ffffffff81565289>] usb_hidinput_input_event+0x89/0x120 stack backtrace: CPU: 0 PID: 5502 Comm: Xorg Not tainted 3.9.0+ #94 Hardware name: Dell Inc. OptiPlex 390/0M5DCD, BIOS A09 07/24/2012 0000000000000001 ffff8800689c7c38 ffffffff816f249f ffff8800689c7c68 ffffffff810acb1d 0000000000000000 ffffffff81a03ac7 000000000000019d 0000000000000000 ffff8800689c7c90 ffffffff8107cda7 0000000000000000 Call Trace: [<ffffffff816f249f>] dump_stack+0x19/0x1b [<ffffffff810acb1d>] lockdep_rcu_suspicious+0xfd/0x130 [<ffffffff8107cda7>] __might_sleep+0xc7/0x230 [<ffffffff816f7770>] mutex_lock_nested+0x40/0x3a0 [<ffffffff81312ac4>] ? vsnprintf+0x354/0x640 [<ffffffff81553cc4>] hid_debug_event+0x34/0x100 [<ffffffff81554197>] hid_dump_input+0x67/0xa0 [<ffffffff81556430>] hid_set_field+0x50/0x120 [<ffffffff8156529a>] usb_hidinput_input_event+0x9a/0x120 [<ffffffff8150d89e>] input_handle_event+0x8e/0x530 [<ffffffff8150df10>] input_inject_event+0x1d0/0x230 [<ffffffff8150dd82>] ? input_inject_event+0x42/0x230 [<ffffffff81512cae>] evdev_write+0xde/0x160 [<ffffffff81185038>] vfs_write+0xc8/0x1f0 [<ffffffff81185535>] SyS_write+0x55/0xa0 [<ffffffff81704482>] system_call_fastpath+0x16/0x1b BUG: sleeping function called from invalid context at kernel/mutex.c:413 in_atomic(): 1, irqs_disabled(): 1, pid: 5502, name: Xorg INFO: lockdep is turned off. irq event stamp: 1098574 hardirqs last enabled at (1098573): [<ffffffff816fb53f>] _raw_spin_unlock_irqrestore+0x3f/0x70 hardirqs last disabled at (1098574): [<ffffffff816faaf5>] _raw_spin_lock_irqsave+0x25/0xa0 softirqs last enabled at (1098306): [<ffffffff8104971f>] __do_softirq+0x18f/0x3c0 softirqs last disabled at (1097867): [<ffffffff81049ad5>] irq_exit+0xa5/0xb0 CPU: 0 PID: 5502 Comm: Xorg Not tainted 3.9.0+ #94 Hardware name: Dell Inc. OptiPlex 390/0M5DCD, BIOS A09 07/24/2012 ffffffff81a03ac7 ffff8800689c7c68 ffffffff816f249f ffff8800689c7c90 ffffffff8107ce60 0000000000000000 ffff8800689c7fd8 ffff88006a62c800 ffff8800689c7d10 ffffffff816f7770 ffff8800689c7d00 ffffffff81312ac4 Call Trace: [<ffffffff816f249f>] dump_stack+0x19/0x1b [<ffffffff8107ce60>] __might_sleep+0x180/0x230 [<ffffffff816f7770>] mutex_lock_nested+0x40/0x3a0 [<ffffffff81312ac4>] ? vsnprintf+0x354/0x640 [<ffffffff81553cc4>] hid_debug_event+0x34/0x100 [<ffffffff81554197>] hid_dump_input+0x67/0xa0 [<ffffffff81556430>] hid_set_field+0x50/0x120 [<ffffffff8156529a>] usb_hidinput_input_event+0x9a/0x120 [<ffffffff8150d89e>] input_handle_event+0x8e/0x530 [<ffffffff8150df10>] input_inject_event+0x1d0/0x230 [<ffffffff8150dd82>] ? input_inject_event+0x42/0x230 [<ffffffff81512cae>] evdev_write+0xde/0x160 [<ffffffff81185038>] vfs_write+0xc8/0x1f0 [<ffffffff81185535>] SyS_write+0x55/0xa0 [<ffffffff81704482>] system_call_fastpath+0x16/0x1b Reported-by: majianpeng <majianpeng@gmail.com> Reported-by: Benjamin Tissoires <benjamin.tissoires@gmail.com> Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>		2013-05-06 13:07:33 +02:00
..
accessibility
acpi	PCI changes for the v3.10 merge window:	2013-04-29 09:30:25 -07:00
amba
ata	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-04-30 09:36:50 -07:00
atm
auxdisplay
base	Merge branch 'for-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq	2013-04-29 19:07:40 -07:00
bcma
block	drbd: rename random32() to prandom_u32()	2013-04-29 18:28:42 -07:00
bluetooth
bus
cdrom
char	Char / Misc driver update for 3.10-rc1	2013-04-29 11:18:34 -07:00
clk	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-04-30 09:36:50 -07:00
clocksource	Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2013-04-30 08:15:40 -07:00
connector
cpufreq	cpufreq / intel_pstate: Set timer timeout correctly	2013-04-08 22:09:23 +02:00
cpuidle
crypto	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-04-30 09:36:50 -07:00
dca
devfreq
dio
dma	dmaengine: at_hdmac: fix race condition in atc_advance_work()	2013-04-18 08:54:22 -07:00
edac	amd64_edac: Add Family 16h support	2013-04-19 12:46:50 +02:00
eisa	PCI changes for the v3.10 merge window:	2013-04-29 09:30:25 -07:00
extcon	This is small fixes for extcon driver.	2013-04-08 16:50:23 -07:00
firewire
firmware	firmware, memmap: fix firmware_map_entry leak	2013-04-29 15:54:38 -07:00
gpio	These are the pinctrl changes for v3.10:	2013-04-29 09:40:35 -07:00
gpu	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-04-30 09:36:50 -07:00
hid	HID: debug: fix RCU preemption issue	2013-05-06 13:07:33 +02:00
hsi
hv	Merge branch 'x86-paravirt-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2013-04-30 08:41:21 -07:00
hwmon	Staging driver tree update for 3.10-rc1	2013-04-29 11:34:17 -07:00
hwspinlock
i2c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-04-30 09:36:50 -07:00
ide
idle
iio
infiniband	drivers/infiniband/hw/mlx4: convert to using idr_alloc_cyclic()	2013-04-29 18:28:41 -07:00
input	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input	2013-04-19 09:15:13 -07:00
iommu	Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2013-04-30 08:40:35 -07:00
ipack
irqchip	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-04-30 09:36:50 -07:00
isdn	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-04-30 09:36:50 -07:00
leds
lguest	lguest: rename random32() to prandom_u32()	2013-04-29 18:28:43 -07:00
macintosh
mailbox
md	Revert "block: add missing block_bio_complete() tracepoint"	2013-04-18 09:00:26 -07:00
media	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-04-30 09:36:50 -07:00
memory
memstick
message
mfd	regulator: Updates for v3.10	2013-04-29 16:32:25 -07:00
misc	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-04-30 09:36:50 -07:00
mmc	mmc: rename random32() to prandom_u32()	2013-04-29 18:28:42 -07:00
mtd	mtdchar: remove no-longer-used vma helpers	2013-04-19 10:05:39 -07:00
net	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-04-30 09:36:50 -07:00
nfc
ntb
nubus
of
oprofile
parisc
parport
pci	PCI changes for the v3.10 merge window:	2013-04-29 09:30:25 -07:00
pcmcia
pinctrl	pinctrl: move subsystem mutex to pinctrl_dev struct	2013-04-26 17:01:35 +02:00
platform	Merge branch 'for_linus' of git://cavan.codon.org.uk/platform-drivers-x86	2013-04-18 15:14:34 -07:00
pnp
power	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-04-30 09:36:50 -07:00
pps
ps3
ptp
pwm
rapidio
regulator	Merge remote-tracking branch 'regulator/topic/wm8994' into v3.9-rc8	2013-04-28 02:13:50 +01:00
remoteproc	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-04-30 09:36:50 -07:00
rpmsg	drivers/rpmsg/virtio_rpmsg_bus.c: fix error return code in rpmsg_probe()	2013-04-29 18:28:13 -07:00
rtc	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-04-30 09:36:50 -07:00
s390	TTY/Serial driver update for 3.10-rc1	2013-04-29 12:16:17 -07:00
sbus
scsi	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-04-30 09:36:50 -07:00
sfi
sh
sn
spi	spi: Updates for v3.10	2013-04-29 16:38:41 -07:00
ssb	ssb: implement spurious tone avoidance	2013-04-10 10:31:26 -04:00
ssbi
staging	TTY/Serial driver update for 3.10-rc1	2013-04-29 12:16:17 -07:00
target	target: Fix incorrect fallthrough of ALUA Standby/Offline/Transition CDBs	2013-04-11 01:48:49 -07:00
tc
thermal
tty	TTY/Serial driver update for 3.10-rc1	2013-04-29 12:16:17 -07:00
uio
usb	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-04-30 09:36:50 -07:00
uwb	uwb: rename random32() to prandom_u32()	2013-04-29 18:28:43 -07:00
vfio	PCI changes for the v3.10 merge window:	2013-04-29 09:30:25 -07:00
vhost	Merge git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending	2013-04-12 15:26:42 -07:00
video	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-04-30 09:36:50 -07:00
virt
virtio
vlynq
vme
w1
watchdog	watchdog: Revert the AT91RM9200_WATCHDOG dependency	2013-04-14 09:09:10 +02:00
xen	Features:	2013-04-29 08:16:51 -07:00
zorro
Kconfig
Makefile	USB patches for 3.10-rc1	2013-04-29 12:19:23 -07:00