From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	Runyu Xiao <runyu.xiao@seu.edu.cn>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Subject: [PATCH 6.1 0122/1067] gpio: eic-sprd: use raw_spinlock_t in the irq startup path
Date: Tue, 21 Jul 2026 17:12:03 +0200
Message-ID: <20260721152427.320177980@linuxfoundation.org>
In-Reply-To: <20260721152424.521567757@linuxfoundation.org>
References: <20260721152424.521567757@linuxfoundation.org>
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6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Runyu Xiao <runyu.xiao@seu.edu.cn>

commit 90f0109019e6817eb40a486671b7722d1544ae29 upstream.

sprd_eic_irq_unmask() enables the GPIO IRQ and then updates controller
state through sprd_eic_update(), which takes sprd_eic->lock with
spin_lock_irqsave().  The callback can be reached from irq_startup()
while setting up a requested IRQ.  That path is not sleepable, but on
PREEMPT_RT a regular spinlock_t becomes a sleeping lock.

This issue was found by our static analysis tool and then manually
reviewed against the current tree.

The grounded PoC kept the request_threaded_irq() -> __setup_irq() ->
irq_startup() -> sprd_eic_irq_unmask() -> sprd_eic_update() carrier and
used the original spin_lock_irqsave(&sprd_eic->lock) edge.  Lockdep
reported:

  BUG: sleeping function called from invalid context
  hardirqs last disabled at ... __setup_irq.constprop.0 ... [vuln_msv]
  sprd_rt_spin_lock_irqsave+0x1c/0x30 [vuln_msv]
  sprd_eic_update.constprop.0+0x48/0x90 [vuln_msv]
  sprd_eic_irq_unmask.constprop.0+0x35/0x50 [vuln_msv]
  __setup_irq.constprop.0+0xd/0x30 [vuln_msv]

Convert the Spreadtrum EIC controller lock to raw_spinlock_t.  The
locked section only serializes MMIO register updates and does not contain
sleepable operations, so keeping it non-sleeping is appropriate for the
irqchip callbacks.

Fixes: 25518e024e3a ("gpio: Add Spreadtrum EIC driver support")
Cc: stable@vger.kernel.org
Signed-off-by: Runyu Xiao <runyu.xiao@seu.edu.cn>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20260617154035.1199948-3-runyu.xiao@seu.edu.cn
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpio/gpio-eic-sprd.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/gpio/gpio-eic-sprd.c
+++ b/drivers/gpio/gpio-eic-sprd.c
@@ -94,7 +94,7 @@ struct sprd_eic {
 	struct irq_chip intc;
 	void __iomem *base[SPRD_EIC_MAX_BANK];
 	enum sprd_eic_type type;
-	spinlock_t lock;
+	raw_spinlock_t lock;
 	int irq;
 };
 
@@ -146,7 +146,7 @@ static void sprd_eic_update(struct gpio_
 	unsigned long flags;
 	u32 tmp;
 
-	spin_lock_irqsave(&sprd_eic->lock, flags);
+	raw_spin_lock_irqsave(&sprd_eic->lock, flags);
 	tmp = readl_relaxed(base + reg);
 
 	if (val)
@@ -155,7 +155,7 @@ static void sprd_eic_update(struct gpio_
 		tmp &= ~BIT(SPRD_EIC_BIT(offset));
 
 	writel_relaxed(tmp, base + reg);
-	spin_unlock_irqrestore(&sprd_eic->lock, flags);
+	raw_spin_unlock_irqrestore(&sprd_eic->lock, flags);
 }
 
 static int sprd_eic_read(struct gpio_chip *chip, unsigned int offset, u16 reg)
@@ -606,7 +606,7 @@ static int sprd_eic_probe(struct platfor
 	if (!sprd_eic)
 		return -ENOMEM;
 
-	spin_lock_init(&sprd_eic->lock);
+	raw_spin_lock_init(&sprd_eic->lock);
 	sprd_eic->type = pdata->type;
 
 	sprd_eic->irq = platform_get_irq(pdev, 0);