Niklas Söderlund 8ae954caf4 clocksource/drivers/sh_cmt: Fix potential deadlock when calling runtime PM ... The ch->lock is used to protect the whole enable() and read() of sh_cmt's implementation of struct clocksource. The enable() implementation calls pm_runtime_get_sync() which may result in the clock source to be read() triggering a cyclic lockdep warning for the ch->lock. The sh_cmt driver implement its own balancing of calls to sh_cmt_{enable,disable}() with flags in sh_cmt_{start,stop}(). It does this to deal with that start and stop are shared between the clock source and clock event providers. While this could be improved on verifying corner cases based on any substantial rework on all devices this driver supports might prove hard. As a first step separate the PM handling for clock event and clock source. Always put/get the device when enabling/disabling the clock source but keep the clock event logic unchanged. This allows the sh_cmt implementation of struct clocksource to call PM without holding the ch->lock and avoiding the deadlock. Triggering and log of the deadlock warning, # echo e60f0000.timer > /sys/devices/system/clocksource/clocksource0/current_clocksource [ 46.948370] ====================================================== [ 46.954730] WARNING: possible circular locking dependency detected [ 46.961094] 5.10.0-rc6-arm64-renesas-00001-g0e5fd7414e8b #36 Not tainted [ 46.967985] ------------------------------------------------------ [ 46.974342] migration/0/11 is trying to acquire lock: [ 46.979543] ffff0000403ed220 (&dev->power.lock){-...}-{2:2}, at: __pm_runtime_resume+0x40/0x74 [ 46.988445] [ 46.988445] but task is already holding lock: [ 46.994441] ffff000040ad0298 (&ch->lock){....}-{2:2}, at: sh_cmt_start+0x28/0x210 [ 47.002173] [ 47.002173] which lock already depends on the new lock. [ 47.002173] [ 47.010573] [ 47.010573] the existing dependency chain (in reverse order) is: [ 47.018262] [ 47.018262] -> #3 (&ch->lock){....}-{2:2}: [ 47.024033] lock_acquire.part.0+0x120/0x330 [ 47.028970] lock_acquire+0x64/0x80 [ 47.033105] _raw_spin_lock_irqsave+0x7c/0xc4 [ 47.038130] sh_cmt_start+0x28/0x210 [ 47.042352] sh_cmt_clocksource_enable+0x28/0x50 [ 47.047644] change_clocksource+0x9c/0x160 [ 47.052402] multi_cpu_stop+0xa4/0x190 [ 47.056799] cpu_stopper_thread+0x90/0x154 [ 47.061557] smpboot_thread_fn+0x244/0x270 [ 47.066310] kthread+0x154/0x160 [ 47.070175] ret_from_fork+0x10/0x20 [ 47.074390] [ 47.074390] -> #2 (tk_core.seq.seqcount){----}-{0:0}: [ 47.081136] lock_acquire.part.0+0x120/0x330 [ 47.086070] lock_acquire+0x64/0x80 [ 47.090203] seqcount_lockdep_reader_access.constprop.0+0x74/0x100 [ 47.097096] ktime_get+0x28/0xa0 [ 47.100960] hrtimer_start_range_ns+0x210/0x2dc [ 47.106164] generic_sched_clock_init+0x70/0x88 [ 47.111364] sched_clock_init+0x40/0x64 [ 47.115853] start_kernel+0x494/0x524 [ 47.120156] [ 47.120156] -> #1 (hrtimer_bases.lock){-.-.}-{2:2}: [ 47.126721] lock_acquire.part.0+0x120/0x330 [ 47.136042] lock_acquire+0x64/0x80 [ 47.144461] _raw_spin_lock_irqsave+0x7c/0xc4 [ 47.153721] hrtimer_start_range_ns+0x68/0x2dc [ 47.163054] rpm_suspend+0x308/0x5dc [ 47.171473] rpm_idle+0xc4/0x2a4 [ 47.179550] pm_runtime_work+0x98/0xc0 [ 47.188209] process_one_work+0x294/0x6f0 [ 47.197142] worker_thread+0x70/0x45c [ 47.205661] kthread+0x154/0x160 [ 47.213673] ret_from_fork+0x10/0x20 [ 47.221957] [ 47.221957] -> #0 (&dev->power.lock){-...}-{2:2}: [ 47.236292] check_noncircular+0x128/0x140 [ 47.244907] __lock_acquire+0x13b0/0x204c [ 47.253332] lock_acquire.part.0+0x120/0x330 [ 47.262033] lock_acquire+0x64/0x80 [ 47.269826] _raw_spin_lock_irqsave+0x7c/0xc4 [ 47.278430] __pm_runtime_resume+0x40/0x74 [ 47.286758] sh_cmt_start+0x84/0x210 [ 47.294537] sh_cmt_clocksource_enable+0x28/0x50 [ 47.303449] change_clocksource+0x9c/0x160 [ 47.311783] multi_cpu_stop+0xa4/0x190 [ 47.319720] cpu_stopper_thread+0x90/0x154 [ 47.328022] smpboot_thread_fn+0x244/0x270 [ 47.336298] kthread+0x154/0x160 [ 47.343708] ret_from_fork+0x10/0x20 [ 47.351445] [ 47.351445] other info that might help us debug this: [ 47.351445] [ 47.370225] Chain exists of: [ 47.370225] &dev->power.lock --> tk_core.seq.seqcount --> &ch->lock [ 47.370225] [ 47.392003] Possible unsafe locking scenario: [ 47.392003] [ 47.405314] CPU0 CPU1 [ 47.413569] ---- ---- [ 47.421768] lock(&ch->lock); [ 47.428425] lock(tk_core.seq.seqcount); [ 47.438701] lock(&ch->lock); [ 47.447930] lock(&dev->power.lock); [ 47.455172] [ 47.455172] *** DEADLOCK *** [ 47.455172] [ 47.471433] 3 locks held by migration/0/11: [ 47.479099] #0: ffff8000113c9278 (timekeeper_lock){-.-.}-{2:2}, at: change_clocksource+0x2c/0x160 [ 47.491834] #1: ffff8000113c8f88 (tk_core.seq.seqcount){----}-{0:0}, at: multi_cpu_stop+0xa4/0x190 [ 47.504727] #2: ffff000040ad0298 (&ch->lock){....}-{2:2}, at: sh_cmt_start+0x28/0x210 [ 47.516541] [ 47.516541] stack backtrace: [ 47.528480] CPU: 0 PID: 11 Comm: migration/0 Not tainted 5.10.0-rc6-arm64-renesas-00001-g0e5fd7414e8b #36 [ 47.542147] Hardware name: Renesas Salvator-X 2nd version board based on r8a77965 (DT) [ 47.554241] Call trace: [ 47.560832] dump_backtrace+0x0/0x190 [ 47.568670] show_stack+0x14/0x30 [ 47.576144] dump_stack+0xe8/0x130 [ 47.583670] print_circular_bug+0x1f0/0x200 [ 47.592015] check_noncircular+0x128/0x140 [ 47.600289] __lock_acquire+0x13b0/0x204c [ 47.608486] lock_acquire.part.0+0x120/0x330 [ 47.616953] lock_acquire+0x64/0x80 [ 47.624582] _raw_spin_lock_irqsave+0x7c/0xc4 [ 47.633114] __pm_runtime_resume+0x40/0x74 [ 47.641371] sh_cmt_start+0x84/0x210 [ 47.649115] sh_cmt_clocksource_enable+0x28/0x50 [ 47.657916] change_clocksource+0x9c/0x160 [ 47.666165] multi_cpu_stop+0xa4/0x190 [ 47.674056] cpu_stopper_thread+0x90/0x154 [ 47.682308] smpboot_thread_fn+0x244/0x270 [ 47.690560] kthread+0x154/0x160 [ 47.697927] ret_from_fork+0x10/0x20 [ 47.708447] clocksource: Switched to clocksource e60f0000.timer Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Link: https://lore.kernel.org/r/20201205021921.1456190-2-niklas.soderlund+renesas@ragnatech.se		2020-12-07 20:10:05 +01:00
..
accessibility
acpi	More ACPI updates for 5.10-rc1	2020-10-23 16:38:36 -07:00
amba
android	task_work: cleanup notification modes	2020-10-17 15:05:30 -06:00
ata	Merge branch 'parisc-5.10-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux	2020-10-25 10:59:34 -07:00
atm
auxdisplay
base	More power management updates for 5.10-rc1	2020-10-23 16:27:03 -07:00
bcma
block	xen: branch for v5.10-rc1c	2020-10-25 10:55:35 -07:00
bluetooth	networking changes for the 5.10 merge window	2020-10-15 18:42:13 -07:00
bus	ARM: SoC-related driver updates	2020-10-24 10:39:22 -07:00
cdrom
char	random32: make prandom_u32() output unpredictable	2020-10-24 20:21:57 +02:00
clk	treewide: Convert macro and uses of __section(foo) to __section("foo")	2020-10-25 14:51:49 -07:00
clocksource	clocksource/drivers/sh_cmt: Fix potential deadlock when calling runtime PM	2020-12-07 20:10:05 +01:00
connector
counter
cpufreq	ARM: SoC-related driver updates	2020-10-24 10:39:22 -07:00
cpuidle	powerpc updates for 5.10	2020-10-16 12:21:15 -07:00
crypto	s390 updates for the 5.10 merge window	2020-10-16 12:36:38 -07:00
dax	fuse update for 5.10	2020-10-19 14:28:30 -07:00
dca
devfreq
dio
dma	ARM: SoC-related driver updates	2020-10-24 10:39:22 -07:00
dma-buf	dma-mapping updates for 5.10	2020-10-15 14:43:29 -07:00
edac	EFI changes for v5.10:	2020-10-12 13:26:49 -07:00
eisa
extcon
firewire
firmware	ARM: SoC-related driver updates	2020-10-24 10:39:22 -07:00
fpga
fsi
gnss
gpio	- New Drivers	2020-10-14 15:56:58 -07:00
gpu	ARM: SoC-related driver updates	2020-10-24 10:39:22 -07:00
greybus
hid	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input	2020-10-23 16:16:31 -07:00
hsi
hv	Merge branch 'akpm' (patches from Andrew)	2020-10-16 11:31:55 -07:00
hwmon	ARM: SoC platform updates	2020-10-24 10:33:08 -07:00
hwspinlock
hwtracing	intel_th: pci: Add Alder Lake CPU support	2020-10-05 12:43:54 +02:00
i2c	i2c: core: Restore acpi_walk_dep_device_list() getting called after registering the ACPI i2c devs	2020-10-25 13:33:54 +01:00
i3c	* Fix DAA for the pre-reserved address case	2020-10-17 11:01:01 -07:00
ide	block-5.10-2020-10-12	2020-10-13 12:12:44 -07:00
idle	intel_idle: Ignore _CST if control cannot be taken from the platform	2020-10-16 17:28:32 +02:00
iio	chrome platform changes for 5.10	2020-10-23 10:54:13 -07:00
infiniband	RDMA 5.10 pull request	2020-10-17 11:18:18 -07:00
input	Merge branch 'parisc-5.10-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux	2020-10-25 10:59:34 -07:00
interconnect
iommu	IOMMU Fix for Linux v5.10:	2020-10-20 09:35:06 -07:00
ipack
irqchip	treewide: Convert macro and uses of __section(foo) to __section("foo")	2020-10-25 14:51:49 -07:00
isdn
leds	leds: pwm: Remove platform_data support	2020-10-07 12:02:58 +02:00
lightnvm	lightnvm: fix out-of-bounds write to array devices->info[]	2020-10-16 09:28:45 -06:00
macintosh	powerpc updates for 5.10	2020-10-16 12:21:15 -07:00
mailbox	ARM: SoC-related driver updates	2020-10-24 10:39:22 -07:00
mcb
md	- Improve DM core's bio splitting to use blk_max_size_offset(). Also	2020-10-14 15:05:38 -07:00
media	dma-mapping updates for 5.10	2020-10-15 14:43:29 -07:00
memory	ARM: SoC-related driver updates	2020-10-24 10:39:22 -07:00
memstick
message	SCSI misc on 20201013	2020-10-14 15:15:35 -07:00
mfd	- New Drivers	2020-10-14 15:56:58 -07:00
misc	pci-v5.10-changes	2020-10-22 12:41:00 -07:00
mmc	ARM: SoC platform updates	2020-10-24 10:33:08 -07:00
most
mtd	This pull request contains fixes for UBI and UBIFS	2020-10-18 09:56:50 -07:00
mux
net	Fixes for 5.10-rc1 from the networking tree:	2020-10-23 12:05:49 -07:00
nfc	nfc: remove unneeded break	2020-10-20 10:36:41 -07:00
ntb	Bug fixes for v5.10	2020-10-25 11:12:31 -07:00
nubus
nvdimm	mm/memremap_pages: support multiple ranges per invocation	2020-10-13 18:38:28 -07:00
nvme	nvme-fc: shorten reconnect delay if possible for FC	2020-10-23 12:54:45 +02:00
nvmem
of	treewide: Convert macro and uses of __section(foo) to __section("foo")	2020-10-25 14:51:49 -07:00
opp	Merge branch 'cpufreq/arm/linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm	2020-10-06 12:26:45 +02:00
oprofile
parisc	dma-mapping: split <linux/dma-mapping.h>	2020-10-06 07:07:03 +02:00
parport
pci	VFIO updates for v5.10-rc1	2020-10-22 13:00:44 -07:00
pcmcia
perf
phy	pci-v5.10-changes	2020-10-22 12:41:00 -07:00
pinctrl	Pin control bulk changes for the v5.10 kernel cycle	2020-10-14 15:25:04 -07:00
platform	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input	2020-10-23 16:16:31 -07:00
pnp	PNP: remove the now unused pnp_find_card() function	2020-10-08 18:00:08 +02:00
power	ARM: SoC platform updates	2020-10-24 10:33:08 -07:00
powercap	powercap: Fix typo in Kconfig "Plance" -> "Plane"	2020-10-19 17:40:53 +02:00
pps
ps3
ptp
pwm	ARM: SoC platform updates	2020-10-24 10:33:08 -07:00
rapidio	rapidio: fix the missed put_device() for rio_mport_add_riodev	2020-10-16 11:11:22 -07:00
ras
regulator	Merge remote-tracking branch 'regulator/for-5.10' into regulator-next	2020-10-05 16:54:56 +01:00
remoteproc	remoteproc updates for v5.10	2020-10-22 12:56:33 -07:00
reset	ARM: SoC-related driver updates	2020-10-24 10:39:22 -07:00
rpmsg	rpmsg updates for 5.10	2020-10-22 12:58:21 -07:00
rtc	RTC for 5.10	2020-10-21 11:22:08 -07:00
s390	s390 updates for the 5.10 merge window	2020-10-16 12:36:38 -07:00
sbus
scsi	block-5.10-2020-10-24	2020-10-24 12:46:42 -07:00
sfi
sh
siox
slimbus
soc	ARM: Devicetree updates	2020-10-24 10:44:18 -07:00
soundwire
spi	ARM: SoC platform updates	2020-10-24 10:33:08 -07:00
spmi
ssb
staging	mm: remove kzfree() compatibility definition	2020-10-25 11:39:02 -07:00
target	SCSI misc on 20201023	2020-10-23 16:19:02 -07:00
tc
tee
thermal	treewide: Convert macro and uses of __section(foo) to __section("foo")	2020-10-25 14:51:49 -07:00
thunderbolt
tty	ARM: SoC platform updates	2020-10-24 10:33:08 -07:00
uio
usb	ARM: SoC platform updates	2020-10-24 10:33:08 -07:00
vdpa	vhost,vdpa,virtio: cleanups, fixes	2020-10-23 11:00:57 -07:00
vfio	VFIO updates for v5.10-rc1	2020-10-22 13:00:44 -07:00
vhost	vhost_vdpa: remove unnecessary spin_lock in vhost_vring_call	2020-10-21 10:48:10 -04:00
video	ARM: SoC platform updates	2020-10-24 10:33:08 -07:00
virt
virtio	vhost,vdpa,virtio: cleanups, fixes	2020-10-23 11:00:57 -07:00
visorbus
vlynq
vme
w1	w1: w1_therm: make w1_poll_completion static	2020-10-05 14:49:24 +02:00
watchdog	ARM: SoC platform updates	2020-10-24 10:33:08 -07:00
xen	xen: branch for v5.10-rc1c	2020-10-25 10:55:35 -07:00
zorro
Kconfig
Makefile