Saravana Kannan 7008e58c63 driver core: Fix lockdep warning on wfs_lock ... There's a potential deadlock with the following cycle: wfs_lock --> device_links_lock --> kn->count Fix this by simply dropping the lock around a list_empty() check that's just exported to a sysfs file. The sysfs file output is an instantaneous check anyway and the lock doesn't really add any protection. Lockdep log: [ 48.808132] [ 48.808132] the existing dependency chain (in reverse order) is: [ 48.809069] [ 48.809069] -> #2 (kn->count){++++}: [ 48.809707] __kernfs_remove.llvm.7860393000964815146+0x2d4/0x460 [ 48.810537] kernfs_remove_by_name_ns+0x54/0x9c [ 48.811171] sysfs_remove_file_ns+0x18/0x24 [ 48.811762] device_del+0x2b8/0x5a8 [ 48.812269] __device_link_del+0x98/0xb8 [ 48.812829] device_links_driver_bound+0x210/0x2d8 [ 48.813496] driver_bound+0x44/0xf8 [ 48.814000] really_probe+0x340/0x6e0 [ 48.814526] driver_probe_device+0xb8/0x100 [ 48.815117] device_driver_attach+0x78/0xb8 [ 48.815708] __driver_attach+0xe0/0x194 [ 48.816255] bus_for_each_dev+0xa8/0x11c [ 48.816816] driver_attach+0x24/0x30 [ 48.817331] bus_add_driver+0x100/0x1e0 [ 48.817880] driver_register+0x78/0x114 [ 48.818427] __platform_driver_register+0x44/0x50 [ 48.819089] 0xffffffdbb3227038 [ 48.819551] do_one_initcall+0xd8/0x1e0 [ 48.820099] do_init_module+0xd8/0x298 [ 48.820636] load_module+0x3afc/0x44c8 [ 48.821173] __arm64_sys_finit_module+0xbc/0xf0 [ 48.821807] el0_svc_common+0xbc/0x1d0 [ 48.822344] el0_svc_handler+0x74/0x98 [ 48.822882] el0_svc+0x8/0xc [ 48.823310] [ 48.823310] -> #1 (device_links_lock){+.+.}: [ 48.824036] __mutex_lock_common+0xe0/0xe44 [ 48.824626] mutex_lock_nested+0x28/0x34 [ 48.825185] device_link_add+0xd4/0x4ec [ 48.825734] of_link_to_suppliers+0x158/0x204 [ 48.826347] of_fwnode_add_links+0x50/0x64 [ 48.826928] device_link_add_missing_supplier_links+0x90/0x11c [ 48.827725] fw_devlink_resume+0x58/0x130 [ 48.828296] of_platform_default_populate_init+0xb4/0xd0 [ 48.829030] do_one_initcall+0xd8/0x1e0 [ 48.829578] do_initcall_level+0xb8/0xcc [ 48.830137] do_basic_setup+0x60/0x7c [ 48.830662] kernel_init_freeable+0x128/0x1ac [ 48.831275] kernel_init+0x18/0x29c [ 48.831781] ret_from_fork+0x10/0x18 [ 48.832297] [ 48.832297] -> #0 (wfs_lock){+.+.}: [ 48.832922] __lock_acquire+0xe04/0x2e20 [ 48.833480] lock_acquire+0xbc/0xec [ 48.833984] __mutex_lock_common+0xe0/0xe44 [ 48.834577] mutex_lock_nested+0x28/0x34 [ 48.835136] waiting_for_supplier_show+0x3c/0x98 [ 48.835781] dev_attr_show+0x48/0xb4 [ 48.836295] sysfs_kf_seq_show+0xe8/0x184 [ 48.836864] kernfs_seq_show+0x48/0x8c [ 48.837401] seq_read+0x1c8/0x600 [ 48.837884] kernfs_fop_read+0x68/0x204 [ 48.838431] __vfs_read+0x60/0x214 [ 48.838925] vfs_read+0xbc/0x15c [ 48.839397] ksys_read+0x78/0xe4 [ 48.839869] __arm64_sys_read+0x1c/0x28 [ 48.840416] el0_svc_common+0xbc/0x1d0 [ 48.840953] el0_svc_handler+0x74/0x98 [ 48.841490] el0_svc+0x8/0xc [ 48.841917] [ 48.841917] other info that might help us debug this: [ 48.841917] [ 48.842920] Chain exists of: [ 48.842920] wfs_lock --> device_links_lock --> kn->count [ 48.842920] [ 48.844152] Possible unsafe locking scenario: [ 48.844152] [ 48.844895] CPU0 CPU1 [ 48.845463] ---- ---- [ 48.846032] lock(kn->count); [ 48.846417] lock(device_links_lock); [ 48.847203] lock(kn->count); [ 48.847902] lock(wfs_lock); [ 48.848276] [ 48.848276] *** DEADLOCK *** Reported-by: Cheng-Jui.Wang@mediatek.com Signed-off-by: Saravana Kannan <saravanak@google.com> Link: https://lore.kernel.org/r/20201104205431.3795207-1-saravanak@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2020-11-09 18:17:52 +01:00
..
accessibility
acpi	Merge branches 'acpi-button' and 'acpi-dock'	2020-10-30 16:31:20 +01:00
amba
android	task_work: cleanup notification modes	2020-10-17 15:05:30 -06:00
ata	libata-5.10-2020-10-30	2020-10-30 14:51:01 -07:00
atm
auxdisplay
base	driver core: Fix lockdep warning on wfs_lock	2020-11-09 18:17:52 +01:00
bcma
block	null_blk: Fix scheduling in atomic with zoned mode	2020-11-06 09:36:42 -07:00
bluetooth	Bluetooth: btintel: Replace zero-length array with flexible-array member	2020-10-30 16:57:41 -05:00
bus	ARM: SoC-related driver updates	2020-10-24 10:39:22 -07:00
cdrom
char	tpm: efi: Don't create binary_bios_measurements file for an empty log	2020-11-06 18:21:08 +02:00
clk	treewide: Convert macro and uses of __section(foo) to __section("foo")	2020-10-25 14:51:49 -07:00
clocksource	treewide: Convert macro and uses of __section(foo) to __section("foo")	2020-10-25 14:51:49 -07:00
connector
counter
cpufreq	cpufreq: Introduce cpufreq_driver_test_flags()	2020-10-29 14:07:30 +01:00
cpuidle	powerpc updates for 5.10	2020-10-16 12:21:15 -07:00
crypto	crypto: sun8x-ce*: update entries to its documentation	2020-10-28 11:41:15 -06:00
dax	fuse update for 5.10	2020-10-19 14:28:30 -07:00
dca
devfreq
dio
dma	misc: mic: remove the MIC drivers	2020-10-28 19:12:03 +01:00
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 SCMI fixes for v5.10	2020-10-26 12:40:02 +01:00
fpga
fsi
gnss
gpio	- New Drivers	2020-10-14 15:56:58 -07:00
gpu	drm fixes for 5.10-rc3	2020-11-06 12:54:00 -08:00
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	hyperv-fixes for 5.10-rc3	2020-11-05 11:32:03 -08:00
hwmon	ARM: SoC platform updates	2020-10-24 10:33:08 -07:00
hwspinlock
hwtracing	coresight: cti: Initialize dynamic sysfs attributes	2020-10-29 20:10:25 +01:00
i2c	i2c: designware: slave should do WRITE_REQUESTED before WRITE_RECEIVED	2020-11-06 16:02:00 +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: Fix max_cstate for processor models without C-state tables	2020-10-27 19:03:53 +01:00
iio	chrome platform changes for 5.10	2020-10-23 10:54:13 -07:00
infiniband	RDMA 5.10 second rc pull request	2020-11-05 11:25:02 -08:00
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	interconnect: qcom: use icc_sync state for sm8[12]50	2020-10-27 16:01:22 +02:00
iommu	iommu: Fix a check in iommu_check_bind_data()	2020-11-03 14:55:51 +01:00
ipack
irqchip	A set of fixes for interrupt chip drivers:	2020-11-08 09:52:57 -08:00
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: mptfusion: Fix null pointer dereferences in mptscsih_remove()	2020-10-26 16:57:18 -04:00
mfd	- New Drivers	2020-10-14 15:56:58 -07:00
misc	Char/Misc fixes/removals for 5.10-rc2	2020-11-01 10:05:16 -08:00
mmc	MMC host:	2020-10-30 11:04:11 -07:00
most
mtd	mtd: rawnand: stm32_fmc2: fix broken ECC	2020-10-30 18:24:51 +01:00
mux
net	Networking fixes for 5.10-rc3, including fixes from wireless, can,	2020-11-06 11:50:28 -08:00
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 fixes for 5.10:	2020-11-05 07:10:50 -07:00
nvmem
of	of: Drop superfluous ULL suffix for ~0	2020-11-02 09:32:46 -08:00
opp	opp: Reduce the size of critical section in _opp_table_kref_release()	2020-10-27 13:21:03 +05:30
oprofile
parisc	dma-mapping: split <linux/dma-mapping.h>	2020-10-06 07:07:03 +02:00
parport
pci	PCI: mvebu: Fix duplicate resource requests	2020-11-04 13:55:30 -06:00
pcmcia
perf	perf: arm-cmn: Fix conversion specifiers for node type	2020-10-01 22:30:07 +01:00
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: fix kernel-doc markups	2020-10-27 19:23:04 +01:00
power	ARM: SoC platform updates	2020-10-24 10:33:08 -07:00
powercap	powercap/intel_rapl: remove unneeded semicolon	2020-11-02 18:04:34 +01:00
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	regulator: defer probe when trying to get voltage from unresolved supply	2020-11-03 13:19:01 +00:00
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/pkey: fix paes selftest failure with paes and pkey static build	2020-11-03 15:12:16 +01:00
sbus
scsi	SCSI fixes on 20201106	2020-11-06 15:24:12 -08:00
sfi
sh
siox
slimbus
soc	soc: ti: ti_sci_pm_domains: check for proper args count in xlate	2020-10-29 22:13:38 +01:00
soundwire	soundwire updates for 5.10-rc1	2020-10-01 22:59:55 +02:00
spi	spi: bcm2835: remove use of uninitialized gpio flags variable	2020-11-06 11:23:26 +00:00
spmi
ssb
staging	This pull contains a series of warning fixes from Mauro; once applied, the	2020-11-03 13:14:14 -08:00
target	scsi: target: tcmu: Replace zero-length array with flexible-array member	2020-10-29 17:22:59 -05:00
tc
tee	Reenable kernel login method for kernel TEE client API	2020-10-26 10:55:56 +01:00
thermal	treewide: Convert macro and uses of __section(foo) to __section("foo")	2020-10-25 14:51:49 -07:00
thunderbolt
tty	TTY/Serial fixes for 5.10-rc3	2020-11-08 11:28:08 -08:00
uio
usb	USB-serial fixes for 5.10-rc3	2020-11-07 15:56:37 +01:00
vdpa	vhost,vdpa: fixes	2020-10-31 14:41:48 -07:00
vfio	vfio/pci: Bypass IGD init in case of -ENODEV	2020-11-03 11:07:40 -07:00
vhost	vdpa: handle irq bypass register failure case	2020-10-30 04:02:53 -04:00
video	A couple of x86 fixes which missed rc1 due to my stupidity:	2020-10-27 14:39:29 -07:00
virt	virt: vbox: simplify the return expression of vbg_input_open()	2020-10-02 11:36:13 +02:00
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