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Subject[tip:irq/urgent] irqchip/renesas-intc-irqpin: Use a separate lockdep class
Commit-ID:  769b5cf78e6c653c2f513649ee6c4e7a06723872
Author: Geert Uytterhoeven <>
AuthorDate: Wed, 9 Sep 2015 13:42:54 +0200
Committer: Thomas Gleixner <>
CommitDate: Tue, 15 Sep 2015 17:06:29 +0200

irqchip/renesas-intc-irqpin: Use a separate lockdep class

The renesas-intc-irqpin interrupt controller is cascaded to the GIC.
Hence when propagating wake-up settings to its parent interrupt
controller, the following lockdep warning is printed:

[ INFO: possible recursive locking detected ]
4.2.0-armadillo-10725-g50fcd7643c034198 #781 Not tainted
s2ram/1179 is trying to acquire lock:
(&irq_desc_lock_class){-.-...}, at: [<c005bb54>] __irq_get_desc_lock+0x78/0x94

but task is already holding lock:
(&irq_desc_lock_class){-.-...}, at: [<c005bb54>] __irq_get_desc_lock+0x78/0x94

other info that might help us debug this:
Possible unsafe locking scenario:


*** DEADLOCK ***

May be due to missing lock nesting notation

7 locks held by s2ram/1179:
#0: (sb_writers#7){.+.+.+}, at: [<c00c9708>] __sb_start_write+0x64/0xb8
#1: (&of->mutex){+.+.+.}, at: [<c0125a00>] kernfs_fop_write+0x78/0x1a0
#2: (s_active#23){.+.+.+}, at: [<c0125a08>] kernfs_fop_write+0x80/0x1a0
#3: (autosleep_lock){+.+.+.}, at: [<c0058244>] pm_autosleep_lock+0x18/0x20
#4: (pm_mutex){+.+.+.}, at: [<c0057e50>] pm_suspend+0x54/0x248
#5: (&dev->mutex){......}, at: [<c0243a20>] __device_suspend+0xdc/0x240
#6: (&irq_desc_lock_class){-.-...}, at: [<c005bb54>] __irq_get_desc_lock+0x78/0x94

stack backtrace:
CPU: 0 PID: 1179 Comm: s2ram Not tainted 4.2.0-armadillo-10725-g50fcd7643c034198

Hardware name: Generic R8A7740 (Flattened Device Tree)
[<c00129f4>] (dump_backtrace) from [<c0012bec>] (show_stack+0x18/0x1c)
[<c0012bd4>] (show_stack) from [<c03f5d94>] (dump_stack+0x20/0x28)
[<c03f5d74>] (dump_stack) from [<c00514d4>] (__lock_acquire+0x67c/0x1b88)
[<c0050e58>] (__lock_acquire) from [<c0052df8>] (lock_acquire+0x9c/0xbc)
[<c0052d5c>] (lock_acquire) from [<c03fb068>] (_raw_spin_lock_irqsave+0x44/0x58)
[<c03fb024>] (_raw_spin_lock_irqsave) from [<c005bb54>] (__irq_get_desc_lock+0x78/0x94
[<c005badc>] (__irq_get_desc_lock) from [<c005c3d8>] (irq_set_irq_wake+0x28/0x100)
[<c005c3b0>] (irq_set_irq_wake) from [<c01e50d0>] (intc_irqpin_irq_set_wake+0x24/0x4c)
[<c01e50ac>] (intc_irqpin_irq_set_wake) from [<c005c17c>] (set_irq_wake_real+0x3c/0x50
[<c005c140>] (set_irq_wake_real) from [<c005c414>] (irq_set_irq_wake+0x64/0x100)
[<c005c3b0>] (irq_set_irq_wake) from [<c02a19b4>] (gpio_keys_suspend+0x60/0xa0)
[<c02a1954>] (gpio_keys_suspend) from [<c023b750>] (platform_pm_suspend+0x3c/0x5c)

Avoid this false positive by using a separate lockdep class for INTC
External IRQ Pin interrupts.

Signed-off-by: Geert Uytterhoeven <>
Cc: Grygorii Strashko <>
Cc: Magnus Damm <>
Cc: Jason Cooper <>
Signed-off-by: Thomas Gleixner <>
drivers/irqchip/irq-renesas-intc-irqpin.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/irqchip/irq-renesas-intc-irqpin.c b/drivers/irqchip/irq-renesas-intc-irqpin.c
index 0670ab4..67797ee 100644
--- a/drivers/irqchip/irq-renesas-intc-irqpin.c
+++ b/drivers/irqchip/irq-renesas-intc-irqpin.c
@@ -332,6 +332,12 @@ static irqreturn_t intc_irqpin_shared_irq_handler(int irq, void *dev_id)
return status;

+ * This lock class tells lockdep that INTC External IRQ Pin irqs are in a
+ * different category than their parents, so it won't report false recursion.
+ */
+static struct lock_class_key intc_irqpin_irq_lock_class;
static int intc_irqpin_irq_domain_map(struct irq_domain *h, unsigned int virq,
irq_hw_number_t hw)
@@ -342,6 +348,7 @@ static int intc_irqpin_irq_domain_map(struct irq_domain *h, unsigned int virq,

intc_irqpin_dbg(&p->irq[hw], "map");
irq_set_chip_data(virq, h->host_data);
+ irq_set_lockdep_class(virq, &intc_irqpin_irq_lock_class);
irq_set_chip_and_handler(virq, &p->irq_chip, handle_level_irq);
set_irq_flags(virq, IRQF_VALID); /* kill me now */
return 0;

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