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68 lines
2.4 KiB
68 lines
2.4 KiB
From 9588c91936434166007c3a15ad7f4e2f3729c5e7 Mon Sep 17 00:00:00 2001
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From: Stephen Boyd <sboyd@codeaurora.org>
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Date: Thu, 6 Mar 2014 22:44:40 -0800
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Subject: [PATCH 026/182] pinctrl: msm: Silence recursive lockdep warning
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If a driver calls enable_irq_wake() on a gpio turned interrupt
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from the msm pinctrl driver we'll get a lockdep warning like so:
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=============================================
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[ INFO: possible recursive locking detected ]
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3.14.0-rc3 #2 Not tainted
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---------------------------------------------
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modprobe/52 is trying to acquire lock:
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(&irq_desc_lock_class){-.....}, at: [<c026aea0>] __irq_get_desc_lock+0x48/0x88
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but task is already holding lock:
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(&irq_desc_lock_class){-.....}, at: [<c026aea0>] __irq_get_desc_lock+0x48/0x88
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other info that might help us debug this:
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Possible unsafe locking scenario:
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CPU0
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----
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lock(&irq_desc_lock_class);
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lock(&irq_desc_lock_class);
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*** DEADLOCK ***
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May be due to missing lock nesting notation
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4 locks held by modprobe/52:
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#0: (&__lockdep_no_validate__){......}, at: [<c04f2864>] __driver_attach+0x48/0x98
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#1: (&__lockdep_no_validate__){......}, at: [<c04f2874>] __driver_attach+0x58/0x98
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#2: (&irq_desc_lock_class){-.....}, at: [<c026aea0>] __irq_get_desc_lock+0x48/0x88
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#3: (&(&pctrl->lock)->rlock){......}, at: [<c04bb4b8>] msm_gpio_irq_set_wake+0x20/0xa8
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Silence it by putting the gpios into their own lock class.
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Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
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Acked-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
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Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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---
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drivers/pinctrl/pinctrl-msm.c | 7 +++++++
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1 file changed, 7 insertions(+)
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--- a/drivers/pinctrl/pinctrl-msm.c
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+++ b/drivers/pinctrl/pinctrl-msm.c
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@@ -857,6 +857,12 @@ static void msm_gpio_irq_handler(unsigne
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chained_irq_exit(chip, desc);
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}
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+/*
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+ * This lock class tells lockdep that GPIO irqs are in a different
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+ * category than their parents, so it won't report false recursion.
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+ */
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+static struct lock_class_key gpio_lock_class;
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+
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static int msm_gpio_init(struct msm_pinctrl *pctrl)
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{
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struct gpio_chip *chip;
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@@ -895,6 +901,7 @@ static int msm_gpio_init(struct msm_pinc
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for (i = 0; i < chip->ngpio; i++) {
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irq = irq_create_mapping(pctrl->domain, i);
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+ irq_set_lockdep_class(irq, &gpio_lock_class);
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irq_set_chip_and_handler(irq, &msm_gpio_irq_chip, handle_edge_irq);
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irq_set_chip_data(irq, pctrl);
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}
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