[PATCH v4] ARM: davinci: da8xx: Fix sleeping function called from invalid context
David Lechner
david at lechnology.com
Sun Dec 4 19:44:22 PST 2016
On 12/02/2016 08:53 AM, Alexandre Bailon wrote:
> Everytime the usb20 phy is enabled, there is a
> "sleeping function called from invalid context" BUG.
>
> clk_enable() from arch/arm/mach-davinci/clock.c uses spin_lock_irqsave()
> before to invoke the callback usb20_phy_clk_enable().
> usb20_phy_clk_enable() uses clk_get() and clk_enable_prepapre()
> which may sleep.
> Move clk_get() to da8xx_register_usb20_phy_clk() and
> replace clk_prepare_enable() by clk_enable().
>
> Signed-off-by: Alexandre Bailon <abailon at baylibre.com>
> ---
> arch/arm/mach-davinci/usb-da8xx.c | 28 +++++++++++++++-------------
> 1 file changed, 15 insertions(+), 13 deletions(-)
>
> diff --git a/arch/arm/mach-davinci/usb-da8xx.c b/arch/arm/mach-davinci/usb-da8xx.c
> index b010e5f..704f506 100644
> --- a/arch/arm/mach-davinci/usb-da8xx.c
> +++ b/arch/arm/mach-davinci/usb-da8xx.c
> @@ -22,6 +22,8 @@
> #define DA8XX_USB0_BASE 0x01e00000
> #define DA8XX_USB1_BASE 0x01e25000
>
> +static struct clk *usb20_clk;
> +
> static struct platform_device da8xx_usb_phy = {
> .name = "da8xx-usb-phy",
> .id = -1,
> @@ -158,21 +160,14 @@ int __init da8xx_register_usb_refclkin(int rate)
>
> static void usb20_phy_clk_enable(struct clk *clk)
> {
> - struct clk *usb20_clk;
> int err;
> u32 val;
> u32 timeout = 500000; /* 500 msec */
>
> val = readl(DA8XX_SYSCFG0_VIRT(DA8XX_CFGCHIP2_REG));
>
> - usb20_clk = clk_get(&da8xx_usb20_dev.dev, "usb20");
> - if (IS_ERR(usb20_clk)) {
> - pr_err("could not get usb20 clk: %ld\n", PTR_ERR(usb20_clk));
> - return;
> - }
> -
> /* The USB 2.O PLL requires that the USB 2.O PSC is enabled as well. */
> - err = clk_prepare_enable(usb20_clk);
> + err = clk_enable(usb20_clk);
> if (err) {
> pr_err("failed to enable usb20 clk: %d\n", err);
> clk_put(usb20_clk);
Need to remove clk_put() here.
> @@ -197,8 +192,7 @@ static void usb20_phy_clk_enable(struct clk *clk)
>
> pr_err("Timeout waiting for USB 2.0 PHY clock good\n");
> done:
> - clk_disable_unprepare(usb20_clk);
> - clk_put(usb20_clk);
> + clk_disable(usb20_clk);
> }
>
> static void usb20_phy_clk_disable(struct clk *clk)
> @@ -285,11 +279,19 @@ static struct clk_lookup usb20_phy_clk_lookup =
> int __init da8xx_register_usb20_phy_clk(bool use_usb_refclkin)
> {
> struct clk *parent;
> - int ret = 0;
> + int ret;
> +
> + usb20_clk = clk_get(&da8xx_usb20_dev.dev, "usb20");
> + ret = PTR_ERR_OR_ZERO(usb20_clk);
> + if (ret)
> + return ret;
>
> parent = clk_get(NULL, use_usb_refclkin ? "usb_refclkin" : "pll0_aux");
> - if (IS_ERR(parent))
> - return PTR_ERR(parent);
> + ret = PTR_ERR_OR_ZERO(parent);
> + if (ret) {
> + clk_put(usb20_clk);
> + return ret;
> + }
>
> usb20_phy_clk.parent = parent;
> ret = clk_register(&usb20_phy_clk);
>
I have just tried this patch with a bunch of kernel hacking options
enabled. I am getting the message show at the end of this email. We
still have the problem of nested spin locks due to nested calls to
clk_enable(). So, really, we need to use __clk_enable() and
__clk_disable() from arch/arm/mach-davinci/clock.c in
usb20_phy_clk_enable() above.
Applying the following patch on top of your patch fixed the recursive
lock message.
---
diff --git a/arch/arm/mach-davinci/clock.c b/arch/arm/mach-davinci/clock.c
index df42c93..4fba579 100644
--- a/arch/arm/mach-davinci/clock.c
+++ b/arch/arm/mach-davinci/clock.c
@@ -31,7 +31,7 @@ static LIST_HEAD(clocks);
static DEFINE_MUTEX(clocks_mutex);
static DEFINE_SPINLOCK(clockfw_lock);
-static void __clk_enable(struct clk *clk)
+void __clk_enable(struct clk *clk)
{
if (clk->parent)
__clk_enable(clk->parent);
@@ -44,7 +44,7 @@ static void __clk_enable(struct clk *clk)
}
}
-static void __clk_disable(struct clk *clk)
+void __clk_disable(struct clk *clk)
{
if (WARN_ON(clk->usecount == 0))
return;
diff --git a/arch/arm/mach-davinci/clock.h b/arch/arm/mach-davinci/clock.h
index e2a5437..8493242 100644
--- a/arch/arm/mach-davinci/clock.h
+++ b/arch/arm/mach-davinci/clock.h
@@ -136,6 +136,9 @@ int davinci_clk_reset(struct clk *clk, bool reset);
extern struct platform_device davinci_wdt_device;
extern void davinci_watchdog_reset(struct platform_device *);
+void __clk_enable(struct clk *clk);
+void __clk_disable(struct clk *clk);
+
#endif
#endif
diff --git a/arch/arm/mach-davinci/usb-da8xx.c
b/arch/arm/mach-davinci/usb-da8xx
.c
index 896d014..80ba0df 100644
--- a/arch/arm/mach-davinci/usb-da8xx.c
+++ b/arch/arm/mach-davinci/usb-da8xx.c
@@ -160,19 +160,13 @@ int __init da8xx_register_usb_refclkin(int rate)
static void usb20_phy_clk_enable(struct clk *clk)
{
- int err;
u32 val;
u32 timeout = 500000; /* 500 msec */
val = readl(DA8XX_SYSCFG0_VIRT(DA8XX_CFGCHIP2_REG));
/* The USB 2.O PLL requires that the USB 2.O PSC is enabled as
well. */
- err = clk_enable(usb20_clk);
- if (err) {
- pr_err("failed to enable usb20 clk: %d\n", err);
- clk_put(usb20_clk);
- return;
- }
+ __clk_enable(usb20_clk);
/*
* Turn on the USB 2.0 PHY, but just the PLL, and not OTG. The
USB 1.1
@@ -192,7 +186,7 @@ static void usb20_phy_clk_enable(struct clk *clk)
pr_err("Timeout waiting for USB 2.0 PHY clock good\n");
done:
- clk_disable(usb20_clk);
+ __clk_disable(usb20_clk);
}
static void usb20_phy_clk_disable(struct clk *clk)
---
=============================================
[ INFO: possible recursive locking detected ]
4.9.0-rc8-dlech-ev3-lms2012+ #22 Not tainted
---------------------------------------------
swapper/1 is trying to acquire lock:
(
clockfw_lock
){......}
, at:
[<c0014884>] clk_enable+0x24/0x50
k:
(
clockfw_lock
){......}
, at:
[<c0014884>] clk_enable+0x24/0x50
ebug this:
Possible unsafe locking scenario:
CPU0
----
lock(
clockfw_lock
);
lock(
clockfw_lock
);
May be due to missing lock nesting notation
4 locks held by swapper/1:
#0:
(
&dev->mutex
){......}
, at:
[<c02bd60c>] __driver_attach+0x68/0xb4
#1:
(
&dev->mutex
){......}
, at:
[<c02bd61c>] __driver_attach+0x78/0xb4
#2:
(
&phy->mutex
){+.+...}
, at:
[<c025ee18>] phy_power_on+0x5c/0xe4
#3:
(
clockfw_lock
){......}
, at:
[<c0014884>] clk_enable+0x24/0x50
CPU: 0 PID: 1 Comm: swapper Not tainted 4.9.0-rc8-dlech-ev3-lms2012+ #22
Hardware name: Generic DA850/OMAP-L138/AM18x
Backtrace:
[<c000d824>] (dump_backtrace) from [<c000dac4>] (show_stack+0x18/0x1c)
r7:c0e998a4 r6:c0820750 r5:c0820750 r4:c3838000
[<c000daac>] (show_stack) from [<c02393dc>] (dump_stack+0x20/0x28)
[<c02393bc>] (dump_stack) from [<c004bd7c>] (__lock_acquire+0x10f4/0x167c)
[<c004ac88>] (__lock_acquire) from [<c004c6ac>] (lock_acquire+0x78/0x98)
r10:00000000 r9:c06a5ed4 r8:00000000 r7:00000001 r6:60000093 r5:00000000
r4:ffffe000
[<c004c634>] (lock_acquire) from [<c04d8fac>]
(_raw_spin_lock_irqsave+0x60/0x74)
r7:0000003b r6:c0014884 r5:80000093 r4:c06b09a0
[<c04d8f4c>] (_raw_spin_lock_irqsave) from [<c0014884>]
(clk_enable+0x24/0x50)
r6:c06f69f4 r5:0001ef02 r4:c06b3398
[<c0014860>] (clk_enable) from [<c0015c74>] (usb20_phy_clk_enable+0x24/0xb8)
r5:0001ef02 r4:c06f69f0
[<c0015c50>] (usb20_phy_clk_enable) from [<c0014858>]
(__clk_enable+0x74/0x7c)
r9:c06a5ed4 r8:00000000 r7:0000003b r6:c3a6ca00 r5:80000013 r4:c06b7ee8
[<c00147e4>] (__clk_enable) from [<c0014808>] (__clk_enable+0x24/0x7c)
r4:c06b8648
[<c00147e4>] (__clk_enable) from [<c0014890>] (clk_enable+0x30/0x50)
r4:c06b8648
[<c0014860>] (clk_enable) from [<c025f43c>]
(da8xx_usb11_phy_power_on+0x30/0x80)
r5:c3a54050 r4:c06b8648
[<c025f40c>] (da8xx_usb11_phy_power_on) from [<c025ee3c>]
(phy_power_on+0x80/0xe4)
r5:c3a6c800 r4:fffffdf4
[<c025edbc>] (phy_power_on) from [<c032243c>] (ohci_da8xx_enable+0x4c/0x80)
r7:0000003b r6:c3af6000 r5:c3af6000 r4:00000000
[<c03223f0>] (ohci_da8xx_enable) from [<c03224f0>]
(ohci_da8xx_reset+0x1c/0xd8)
r5:00000000 r4:c3af6000
[<c03224d4>] (ohci_da8xx_reset) from [<c0309118>] (usb_add_hcd+0x314/0x834)
r7:0000003b r6:ffffffed r5:00000000 r4:c3af6000
[<c0308e04>] (usb_add_hcd) from [<c032200c>] (ohci_da8xx_probe+0x14c/0x21c)
r9:c06a5ed4 r8:00000000 r7:c38bd010 r6:c38bd000 r5:c3af6000 r4:c38af900
[<c0321ec0>] (ohci_da8xx_probe) from [<c02bec44>]
(platform_drv_probe+0x40/0x8c)
r7:c06e610c r6:c06e610c r5:c38bd010 r4:c0321ec0
[<c02bec04>] (platform_drv_probe) from [<c02bd438>]
(driver_probe_device+0x138/0x2a4)
r7:c06e610c r6:c0e9db10 r5:00000000 r4:c38bd010
[<c02bd300>] (driver_probe_device) from [<c02bd634>]
(__driver_attach+0x90/0xb4)
r9:c06a5ed4 r8:c06f66e0 r7:c06e1250 r6:c06e610c r5:c38bd044 r4:c38bd010
[<c02bd5a4>] (__driver_attach) from [<c02bba5c>]
(bus_for_each_dev+0x74/0x98)
r7:c06e1250 r6:c02bd5a4 r5:c06e610c r4:00000000
[<c02bb9e8>] (bus_for_each_dev) from [<c02bcf2c>] (driver_attach+0x20/0x28)
r6:c39a2300 r5:00000000 r4:c06e610c
[<c02bcf0c>] (driver_attach) from [<c02bca80>] (bus_add_driver+0xd4/0x1f0)
[<c02bc9ac>] (bus_add_driver) from [<c02bdcec>] (driver_register+0xa4/0xe8)
r7:c0698850 r6:00000000 r5:00000000 r4:c06e610c
[<c02bdc48>] (driver_register) from [<c02bebac>]
(__platform_driver_register+0x38/0x4c)
r5:00000000 r4:c06acce4
[<c02beb74>] (__platform_driver_register) from [<c068da20>]
(ohci_da8xx_init+0x64/0x90)
[<c068d9bc>] (ohci_da8xx_init) from [<c00096c0>]
(do_one_initcall+0xb0/0x168)
r5:c068d9bc r4:ffffe000
[<c0009610>] (do_one_initcall) from [<c0676e14>]
(kernel_init_freeable+0x110/0x1cc)
r9:c06a5ed4 r8:c06f66e0 r7:c0698850 r6:000000c1 r5:c06f66e0 r4:00000007
[<c0676d04>] (kernel_init_freeable) from [<c04d37e4>]
(kernel_init+0x10/0xf8)
r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:c04d37d4 r4:00000000
[<c04d37d4>] (kernel_init) from [<c000a2ac>] (ret_from_fork+0x14/0x28)
r5:c04d37d4 r4:00000000
BUG: spinlock lockup suspected on CPU#0, swapper/1
lock: clockfw_lock+0x0/0x20, .magic: dead4ead, .owner: swapper/1,
.owner_cpu: 0
CPU: 0 PID: 1 Comm: swapper Not tainted 4.9.0-rc8-dlech-ev3-lms2012+ #22
Hardware name: Generic DA850/OMAP-L138/AM18x
Backtrace:
[<c000d824>] (dump_backtrace) from [<c000dac4>] (show_stack+0x18/0x1c)
r7:00000000 r6:04605000 r5:c06b09a0 r4:c3838000
[<c000daac>] (show_stack) from [<c02393dc>] (dump_stack+0x20/0x28)
[<c02393bc>] (dump_stack) from [<c004f140>] (spin_dump+0x80/0x94)
[<c004f0c0>] (spin_dump) from [<c004f2c4>] (do_raw_spin_lock+0xdc/0x11c)
r5:00000000 r4:c06b09a0
[<c004f1e8>] (do_raw_spin_lock) from [<c04d8fb4>]
(_raw_spin_lock_irqsave+0x68/0x74)
r10:00000000 r9:c06a5ed4 r8:00000000 r7:0000003b r6:c0014884 r5:80000093
r4:c06b09a0 r3:c3838000
[<c04d8f4c>] (_raw_spin_lock_irqsave) from [<c0014884>]
(clk_enable+0x24/0x50)
r6:c06f69f4 r5:0001ef02 r4:c06b3398
[<c0014860>] (clk_enable) from [<c0015c74>] (usb20_phy_clk_enable+0x24/0xb8)
r5:0001ef02 r4:c06f69f0
[<c0015c50>] (usb20_phy_clk_enable) from [<c0014858>]
(__clk_enable+0x74/0x7c)
r9:c06a5ed4 r8:00000000 r7:0000003b r6:c3a6ca00 r5:80000013 r4:c06b7ee8
[<c00147e4>] (__clk_enable) from [<c0014808>] (__clk_enable+0x24/0x7c)
r4:c06b8648
[<c00147e4>] (__clk_enable) from [<c0014890>] (clk_enable+0x30/0x50)
r4:c06b8648
[<c0014860>] (clk_enable) from [<c025f43c>]
(da8xx_usb11_phy_power_on+0x30/0x80)
r5:c3a54050 r4:c06b8648
[<c025f40c>] (da8xx_usb11_phy_power_on) from [<c025ee3c>]
(phy_power_on+0x80/0xe4)
r5:c3a6c800 r4:fffffdf4
[<c025edbc>] (phy_power_on) from [<c032243c>] (ohci_da8xx_enable+0x4c/0x80)
r7:0000003b r6:c3af6000 r5:c3af6000 r4:00000000
[<c03223f0>] (ohci_da8xx_enable) from [<c03224f0>]
(ohci_da8xx_reset+0x1c/0xd8)
r5:00000000 r4:c3af6000
[<c03224d4>] (ohci_da8xx_reset) from [<c0309118>] (usb_add_hcd+0x314/0x834)
r7:0000003b r6:ffffffed r5:00000000 r4:c3af6000
[<c0308e04>] (usb_add_hcd) from [<c032200c>] (ohci_da8xx_probe+0x14c/0x21c)
r9:c06a5ed4 r8:00000000 r7:c38bd010 r6:c38bd000 r5:c3af6000 r4:c38af900
[<c0321ec0>] (ohci_da8xx_probe) from [<c02bec44>]
(platform_drv_probe+0x40/0x8c)
r7:c06e610c r6:c06e610c r5:c38bd010 r4:c0321ec0
[<c02bec04>] (platform_drv_probe) from [<c02bd438>]
(driver_probe_device+0x138/0x2a4)
r7:c06e610c r6:c0e9db10 r5:00000000 r4:c38bd010
[<c02bd300>] (driver_probe_device) from [<c02bd634>]
(__driver_attach+0x90/0xb4)
r9:c06a5ed4 r8:c06f66e0 r7:c06e1250 r6:c06e610c r5:c38bd044 r4:c38bd010
[<c02bd5a4>] (__driver_attach) from [<c02bba5c>]
(bus_for_each_dev+0x74/0x98)
r7:c06e1250 r6:c02bd5a4 r5:c06e610c r4:00000000
[<c02bb9e8>] (bus_for_each_dev) from [<c02bcf2c>] (driver_attach+0x20/0x28)
r6:c39a2300 r5:00000000 r4:c06e610c
[<c02bcf0c>] (driver_attach) from [<c02bca80>] (bus_add_driver+0xd4/0x1f0)
[<c02bc9ac>] (bus_add_driver) from [<c02bdcec>] (driver_register+0xa4/0xe8)
r7:c0698850 r6:00000000 r5:00000000 r4:c06e610c
[<c02bdc48>] (driver_register) from [<c02bebac>]
(__platform_driver_register+0x38/0x4c)
r5:00000000 r4:c06acce4
[<c02beb74>] (__platform_driver_register) from [<c068da20>]
(ohci_da8xx_init+0x64/0x90)
[<c068d9bc>] (ohci_da8xx_init) from [<c00096c0>]
(do_one_initcall+0xb0/0x168)
r5:c068d9bc r4:ffffe000
[<c0009610>] (do_one_initcall) from [<c0676e14>]
(kernel_init_freeable+0x110/0x1cc)
r9:c06a5ed4 r8:c06f66e0 r7:c0698850 r6:000000c1 r5:c06f66e0 r4:00000007
[<c0676d04>] (kernel_init_freeable) from [<c04d37e4>]
(kernel_init+0x10/0xf8)
r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:c04d37d4 r4:00000000
[<c04d37d4>] (kernel_init) from [<c000a2ac>] (ret_from_fork+0x14/0x28)
r5:c04d37d4 r4:00000000
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