Artem Savkov 71a174b39f pty: do tty_flip_buffer_push without port->lock in pty_write ... b6da31b2c0 "tty: Fix data race in tty_insert_flip_string_fixed_flag" puts tty_flip_buffer_push under port->lock introducing the following possible circular locking dependency: [30129.876566] ====================================================== [30129.876566] WARNING: possible circular locking dependency detected [30129.876567] 5.9.0-rc2+ #3 Tainted: G S W [30129.876568] ------------------------------------------------------ [30129.876568] sysrq.sh/1222 is trying to acquire lock: [30129.876569] ffffffff92c39480 (console_owner){....}-{0:0}, at: console_unlock+0x3fe/0xa90 [30129.876572] but task is already holding lock: [30129.876572] ffff888107cb9018 (&pool->lock/1){-.-.}-{2:2}, at: show_workqueue_state.cold.55+0x15b/0x6ca [30129.876576] which lock already depends on the new lock. [30129.876577] the existing dependency chain (in reverse order) is: [30129.876578] -> #3 (&pool->lock/1){-.-.}-{2:2}: [30129.876581] _raw_spin_lock+0x30/0x70 [30129.876581] __queue_work+0x1a3/0x10f0 [30129.876582] queue_work_on+0x78/0x80 [30129.876582] pty_write+0x165/0x1e0 [30129.876583] n_tty_write+0x47f/0xf00 [30129.876583] tty_write+0x3d6/0x8d0 [30129.876584] vfs_write+0x1a8/0x650 [30129.876588] -> #2 (&port->lock#2){-.-.}-{2:2}: [30129.876590] _raw_spin_lock_irqsave+0x3b/0x80 [30129.876591] tty_port_tty_get+0x1d/0xb0 [30129.876592] tty_port_default_wakeup+0xb/0x30 [30129.876592] serial8250_tx_chars+0x3d6/0x970 [30129.876593] serial8250_handle_irq.part.12+0x216/0x380 [30129.876593] serial8250_default_handle_irq+0x82/0xe0 [30129.876594] serial8250_interrupt+0xdd/0x1b0 [30129.876595] __handle_irq_event_percpu+0xfc/0x850 [30129.876602] -> #1 (&port->lock){-.-.}-{2:2}: [30129.876605] _raw_spin_lock_irqsave+0x3b/0x80 [30129.876605] serial8250_console_write+0x12d/0x900 [30129.876606] console_unlock+0x679/0xa90 [30129.876606] register_console+0x371/0x6e0 [30129.876607] univ8250_console_init+0x24/0x27 [30129.876607] console_init+0x2f9/0x45e [30129.876609] -> #0 (console_owner){....}-{0:0}: [30129.876611] __lock_acquire+0x2f70/0x4e90 [30129.876612] lock_acquire+0x1ac/0xad0 [30129.876612] console_unlock+0x460/0xa90 [30129.876613] vprintk_emit+0x130/0x420 [30129.876613] printk+0x9f/0xc5 [30129.876614] show_pwq+0x154/0x618 [30129.876615] show_workqueue_state.cold.55+0x193/0x6ca [30129.876615] __handle_sysrq+0x244/0x460 [30129.876616] write_sysrq_trigger+0x48/0x4a [30129.876616] proc_reg_write+0x1a6/0x240 [30129.876617] vfs_write+0x1a8/0x650 [30129.876619] other info that might help us debug this: [30129.876620] Chain exists of: [30129.876621] console_owner --> &port->lock#2 --> &pool->lock/1 [30129.876625] Possible unsafe locking scenario: [30129.876626] CPU0 CPU1 [30129.876626] ---- ---- [30129.876627] lock(&pool->lock/1); [30129.876628] lock(&port->lock#2); [30129.876630] lock(&pool->lock/1); [30129.876631] lock(console_owner); [30129.876633] *** DEADLOCK *** [30129.876634] 5 locks held by sysrq.sh/1222: [30129.876634] #0: ffff8881d3ce0470 (sb_writers#3){.+.+}-{0:0}, at: vfs_write+0x359/0x650 [30129.876637] #1: ffffffff92c612c0 (rcu_read_lock){....}-{1:2}, at: __handle_sysrq+0x4d/0x460 [30129.876640] #2: ffffffff92c612c0 (rcu_read_lock){....}-{1:2}, at: show_workqueue_state+0x5/0xf0 [30129.876642] #3: ffff888107cb9018 (&pool->lock/1){-.-.}-{2:2}, at: show_workqueue_state.cold.55+0x15b/0x6ca [30129.876645] #4: ffffffff92c39980 (console_lock){+.+.}-{0:0}, at: vprintk_emit+0x123/0x420 [30129.876648] stack backtrace: [30129.876649] CPU: 3 PID: 1222 Comm: sysrq.sh Tainted: G S W 5.9.0-rc2+ #3 [30129.876649] Hardware name: Intel Corporation 2012 Client Platform/Emerald Lake 2, BIOS ACRVMBY1.86C.0078.P00.1201161002 01/16/2012 [30129.876650] Call Trace: [30129.876650] dump_stack+0x9d/0xe0 [30129.876651] check_noncircular+0x34f/0x410 [30129.876653] __lock_acquire+0x2f70/0x4e90 [30129.876656] lock_acquire+0x1ac/0xad0 [30129.876658] console_unlock+0x460/0xa90 [30129.876660] vprintk_emit+0x130/0x420 [30129.876660] printk+0x9f/0xc5 [30129.876661] show_pwq+0x154/0x618 [30129.876662] show_workqueue_state.cold.55+0x193/0x6ca [30129.876664] __handle_sysrq+0x244/0x460 [30129.876665] write_sysrq_trigger+0x48/0x4a [30129.876665] proc_reg_write+0x1a6/0x240 [30129.876666] vfs_write+0x1a8/0x650 It looks like the commit was aimed to protect tty_insert_flip_string and there is no need for tty_flip_buffer_push to be under this lock. Fixes: b6da31b2c0 ("tty: Fix data race in tty_insert_flip_string_fixed_flag") Signed-off-by: Artem Savkov <asavkov@redhat.com> Acked-by: Jiri Slaby <jirislaby@kernel.org> Link: https://lore.kernel.org/r/20200902120045.3693075-1-asavkov@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2020-09-04 18:10:30 +02:00
..
accessibility	Linux 5.9-rc3	2020-08-31 07:19:25 +02:00
acpi	Merge branch 'acpi-mm'	2020-08-28 21:17:56 +02:00
amba
android
ata	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
atm	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
auxdisplay	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
base	Device properties framework fix for 5.9-rc3	2020-08-28 13:23:31 -07:00
bcma
block	block-5.9-2020-08-28	2020-08-28 16:38:29 -07:00
bluetooth
bus	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
cdrom
char	Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6	2020-08-30 15:53:44 -07:00
clk	More ACPI updates for 5.9-rc1	2020-08-15 08:18:22 -07:00
clocksource	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
connector
counter
cpufreq	Power management fixes for 5.9-rc3	2020-08-28 13:12:09 -07:00
cpuidle	cpuidle: Make CPUIDLE_FLAG_TLB_FLUSHED generic	2020-08-26 12:41:53 +02:00
crypto	Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6	2020-08-30 15:53:44 -07:00
dax	dax: do not print error message for non-persistent memory block device	2020-08-20 11:43:18 -06:00
dca
devfreq
dio
dma	fsldma: fix very broken 32-bit ppc ioread64 functionality	2020-08-29 13:50:56 -07:00
dma-buf
edac	A fix to properly clear ghes_edac driver state on driver remove so that	2020-08-30 10:47:23 -07:00
eisa
extcon
firewire	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
firmware	A set of fixes for interrupt chip drivers:	2020-08-30 11:56:54 -07:00
fpga
fsi
gnss
gpio	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
gpu	drm fixes for 5.9-rc3	2020-08-28 09:46:48 -07:00
greybus
hid	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid	2020-08-25 11:13:29 -07:00
hsi	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
hv	hyperv-fixes for 5.9-rc3	2020-08-26 10:44:15 -07:00
hwmon	hwmon fixes for v5.9-rc3	2020-08-29 12:37:00 -07:00
hwspinlock
hwtracing	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
i2c	Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux	2020-08-29 13:13:44 -07:00
i3c	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
ide	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
idle	cpuidle: Make CPUIDLE_FLAG_TLB_FLUSHED generic	2020-08-26 12:41:53 +02:00
iio	iio: dpot-dac: fix code comment in dpot_dac_read_raw()	2020-08-26 14:02:24 -05:00
infiniband	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
input	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
interconnect
iommu	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
ipack
irqchip	A set of fixes for interrupt chip drivers:	2020-08-30 11:56:54 -07:00
isdn	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
leds
lightnvm	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
macintosh	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
mailbox	iomap: constify ioreadX() iomem argument (as in generic implementation)	2020-08-14 19:56:57 -07:00
mcb
md	block-5.9-2020-08-28	2020-08-28 16:38:29 -07:00
media	media: dib0700: Fix identation issue in dib8096_set_param_override()	2020-08-27 15:36:28 -05:00
memory	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
memstick	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
message	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
mfd	- Bug Fixes	2020-08-28 10:15:33 -07:00
misc	Char/Misc driver fixes for 5.9-rc3	2020-08-26 10:50:50 -07:00
mmc	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
most
mtd
mux	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
net	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
nfc	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
ntb	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
nubus
nvdimm	libnvdimm: KASAN: global-out-of-bounds Read in internal_create_group	2020-08-17 14:47:38 -06:00
nvme	io_uring-5.9-2020-08-23	2020-08-24 11:53:15 -07:00
nvmem
of	of: address: Work around missing device_type property in pcie nodes	2020-08-19 16:30:57 -06:00
opp	opp: Enable resources again if they were disabled earlier	2020-08-20 11:30:22 +05:30
oprofile
parisc
parport	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
pci	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
pcmcia	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
perf	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
phy	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
pinctrl
platform	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
pnp
power	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
powercap
pps
ps3	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
ptp	ptp: ptp_clockmatrix: use i2c_master_send for i2c write	2020-08-19 16:23:22 -07:00
pwm	pwm: Changes for v5.9-rc1	2020-08-14 16:00:09 -07:00
rapidio	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
ras
regulator	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
remoteproc	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
reset	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
rpmsg	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
rtc	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
s390	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
sbus
scsi	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
sfi
sh	iomap: constify ioreadX() iomem argument (as in generic implementation)	2020-08-14 19:56:57 -07:00
siox
slimbus
soc	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
soundwire
spi	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
spmi
ssb	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
staging	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
target	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
tc
tee
thermal	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
thunderbolt	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
tty	pty: do tty_flip_buffer_push without port->lock in pty_write	2020-09-04 18:10:30 +02:00
uio
usb	USB fixes for 5.9-rc3 - take 2	2020-08-30 10:51:03 -07:00
vdpa	vdpa/mlx5: Avoid warnings about shifts on 32-bit platforms	2020-08-26 08:13:59 -04:00
vfio	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
vhost	vhost-iotlb: fix vhost_iotlb_itree_next() documentation	2020-08-26 08:13:59 -04:00
video	Linux 5.9-rc3	2020-08-31 07:19:25 +02:00
virt
virtio	virtio: pci: constify ioreadX() iomem argument (as in generic implementation)	2020-08-14 19:56:57 -07:00
visorbus
vlynq
vme
w1
watchdog	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
xen	xen: branch for v5.9-rc3	2020-08-29 12:44:30 -07:00
zorro
Kconfig
Makefile