[PATCH 5.5 112/120] pinctrl: qcom: Dont lock around irq_set_irq_wake()

From: Greg Kroah-Hartman
Date: Thu Feb 13 2020 - 10:38:03 EST

From: Stephen Boyd <swboyd@xxxxxxxxxxxx>

commit 1d44616e7549d0154c1224a3eee3c407029294dc upstream.

We don't need to hold the local pinctrl lock here to set irq wake on the
summary irq line. Doing so only leads to lockdep warnings instead of
protecting us from anything. Remove the locking.

WARNING: possible circular locking dependency detected
5.4.11 #2 Tainted: G W
------------------------------------------------------
cat/3083 is trying to acquire lock:
ffffff81f4fa58c0 (&irq_desc_lock_class){-.-.}, at: __irq_get_desc_lock+0x64/0x94

but task is already holding lock:
ffffff81f4880c18 (&pctrl->lock){-.-.}, at: msm_gpio_irq_set_wake+0x48/0x7c

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&pctrl->lock){-.-.}:
_raw_spin_lock_irqsave+0x64/0x80
msm_gpio_irq_ack+0x68/0xf4
__irq_do_set_handler+0xe0/0x180
__irq_set_handler+0x60/0x9c
irq_domain_set_info+0x90/0xb4
gpiochip_hierarchy_irq_domain_alloc+0x110/0x200
__irq_domain_alloc_irqs+0x130/0x29c
irq_create_fwspec_mapping+0x1f0/0x300
irq_create_of_mapping+0x70/0x98
of_irq_get+0xa4/0xd4
spi_drv_probe+0x4c/0xb0
really_probe+0x138/0x3f0
driver_probe_device+0x70/0x140
__device_attach_driver+0x9c/0x110
bus_for_each_drv+0x88/0xd0
__device_attach+0xb0/0x160
device_initial_probe+0x20/0x2c
bus_probe_device+0x34/0x94
device_add+0x35c/0x3f0
spi_add_device+0xbc/0x194
of_register_spi_devices+0x2c8/0x408
spi_register_controller+0x57c/0x6fc
spi_geni_probe+0x260/0x328
platform_drv_probe+0x90/0xb0
really_probe+0x138/0x3f0
driver_probe_device+0x70/0x140
device_driver_attach+0x4c/0x6c
__driver_attach+0xcc/0x154
bus_for_each_dev+0x84/0xcc
driver_attach+0x2c/0x38
bus_add_driver+0x108/0x1fc
driver_register+0x64/0xf8
__platform_driver_register+0x4c/0x58
spi_geni_driver_init+0x1c/0x24
do_one_initcall+0x1a4/0x3e8
do_initcall_level+0xb4/0xcc
do_basic_setup+0x30/0x48
kernel_init_freeable+0x124/0x1a8
kernel_init+0x14/0x100
ret_from_fork+0x10/0x18

-> #0 (&irq_desc_lock_class){-.-.}:
__lock_acquire+0xeb4/0x2388
lock_acquire+0x1cc/0x210
_raw_spin_lock_irqsave+0x64/0x80
__irq_get_desc_lock+0x64/0x94
irq_set_irq_wake+0x40/0x144
msm_gpio_irq_set_wake+0x5c/0x7c
set_irq_wake_real+0x40/0x5c
irq_set_irq_wake+0x70/0x144
cros_ec_rtc_suspend+0x38/0x4c
platform_pm_suspend+0x34/0x60
dpm_run_callback+0x64/0xcc
__device_suspend+0x310/0x41c
dpm_suspend+0xf8/0x298
dpm_suspend_start+0x84/0xb4
suspend_devices_and_enter+0xbc/0x620
pm_suspend+0x210/0x348
state_store+0xb0/0x108
kobj_attr_store+0x14/0x24
sysfs_kf_write+0x4c/0x64
kernfs_fop_write+0x15c/0x1fc
__vfs_write+0x54/0x18c
vfs_write+0xe4/0x1a4
ksys_write+0x7c/0xe4
__arm64_sys_write+0x20/0x2c
el0_svc_common+0xa8/0x160
el0_svc_handler+0x7c/0x98
el0_svc+0x8/0xc

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&pctrl->lock);
lock(&irq_desc_lock_class);
lock(&pctrl->lock);
lock(&irq_desc_lock_class);

*** DEADLOCK ***

7 locks held by cat/3083:
#0: ffffff81f06d1420 (sb_writers#7){.+.+}, at: vfs_write+0xd0/0x1a4
#1: ffffff81c8935680 (&of->mutex){+.+.}, at: kernfs_fop_write+0x12c/0x1fc
#2: ffffff81f4c322f0 (kn->count#337){.+.+}, at: kernfs_fop_write+0x134/0x1fc
#3: ffffffe89a641d60 (system_transition_mutex){+.+.}, at: pm_suspend+0x108/0x348
#4: ffffff81f190e970 (&dev->mutex){....}, at: __device_suspend+0x168/0x41c
#5: ffffff81f183d8c0 (lock_class){-.-.}, at: __irq_get_desc_lock+0x64/0x94
#6: ffffff81f4880c18 (&pctrl->lock){-.-.}, at: msm_gpio_irq_set_wake+0x48/0x7c

stack backtrace:
CPU: 4 PID: 3083 Comm: cat Tainted: G W 5.4.11 #2
Hardware name: Google Cheza (rev3+) (DT)
Call trace:
dump_backtrace+0x0/0x174
show_stack+0x20/0x2c
dump_stack+0xc8/0x124
print_circular_bug+0x2ac/0x2c4
check_noncircular+0x1a0/0x1a8
__lock_acquire+0xeb4/0x2388
lock_acquire+0x1cc/0x210
_raw_spin_lock_irqsave+0x64/0x80
__irq_get_desc_lock+0x64/0x94
irq_set_irq_wake+0x40/0x144
msm_gpio_irq_set_wake+0x5c/0x7c
set_irq_wake_real+0x40/0x5c
irq_set_irq_wake+0x70/0x144
cros_ec_rtc_suspend+0x38/0x4c
platform_pm_suspend+0x34/0x60
dpm_run_callback+0x64/0xcc
__device_suspend+0x310/0x41c
dpm_suspend+0xf8/0x298
dpm_suspend_start+0x84/0xb4
suspend_devices_and_enter+0xbc/0x620
pm_suspend+0x210/0x348
state_store+0xb0/0x108
kobj_attr_store+0x14/0x24
sysfs_kf_write+0x4c/0x64
kernfs_fop_write+0x15c/0x1fc
__vfs_write+0x54/0x18c
vfs_write+0xe4/0x1a4
ksys_write+0x7c/0xe4
__arm64_sys_write+0x20/0x2c
el0_svc_common+0xa8/0x160
el0_svc_handler+0x7c/0x98
el0_svc+0x8/0xc

Fixes: 6aced33f4974 ("pinctrl: msm: drop wake_irqs bitmap")
Cc: Douglas Anderson <dianders@xxxxxxxxxxxx>
Cc: Brian Masney <masneyb@xxxxxxxxxxxxx>
Cc: Lina Iyer <ilina@xxxxxxxxxxxxxx>
Cc: Maulik Shah <mkshah@xxxxxxxxxxxxxx>
Signed-off-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20200121180950.36959-1-swboyd@xxxxxxxxxxxx
Reviewed-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/pinctrl/qcom/pinctrl-msm.c | 5 -----
1 file changed, 5 deletions(-)

--- a/drivers/pinctrl/qcom/pinctrl-msm.c
+++ b/drivers/pinctrl/qcom/pinctrl-msm.c
@@ -960,7 +960,6 @@ static int msm_gpio_irq_set_wake(struct
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
struct msm_pinctrl *pctrl = gpiochip_get_data(gc);
- unsigned long flags;

/*
* While they may not wake up when the TLMM is powered off,
@@ -971,12 +970,8 @@ static int msm_gpio_irq_set_wake(struct
if (d->parent_data)
irq_chip_set_wake_parent(d, on);

- raw_spin_lock_irqsave(&pctrl->lock, flags);
-
irq_set_irq_wake(pctrl->irq, on);

- raw_spin_unlock_irqrestore(&pctrl->lock, flags);
-
return 0;
}