FAILED: patch "[PATCH] irqchip/atmel-aic[5]: Disable interrupts in the irq_pm_shutdown() callbacks" failed to apply to 6.6-stable tree

[Sasha Levin <sashal@kernel.org>]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 0ca21fe111457c843624a835641bb490e704bb2f
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107053532-failed-6.6-0ca21fe11145@kernel.org' --subject-prefix 'PATCH 6.6.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From 0ca21fe111457c843624a835641bb490e704bb2f Mon Sep 17 00:00:00 2001
From: Karl Mehltretter <kmehltretter@gmail.com>
Date: Sat, 26 Sep 2026 02:41:24 +0200
Subject: [PATCH] irqchip/atmel-aic[5]: Disable interrupts in the
 irq_pm_shutdown() callbacks

irq_gc_shutdown() calls the irq_pm_shutdown() callbacks from
syscore_shutdown() with interrupts enabled. aic_pm_shutdown() and
aic5_pm_shutdown() take the generic chip lock with raw_spin_lock(), and
irq_gc_eoi() takes the same lock from the interrupt handler. An
interrupt from the chip while the lock is held spins in irq_gc_eoi()
and hangs the reboot.

Lockdep reports this on every reboot of a SAM9X75 Curiosity board:

  WARNING: inconsistent lock state
  inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
  busybox/101 [HC0[0]:SC0[0]:HE1:SE1] takes:
  c1c2b434 (&gc->lock){?.-.}-{2:2}, at: aic5_pm_shutdown+0x34/0xd8
  {IN-HARDIRQ-W} state was registered at:
    ...
    irq_gc_eoi+0x28/0x60
    handle_fasteoi_irq+0x120/0x214
  ...
   aic5_pm_shutdown from irq_gc_shutdown+0x4c/0x58
   irq_gc_shutdown from syscore_shutdown+0x5c/0x9c
   syscore_shutdown from kernel_restart+0x34/0x78
   kernel_restart from sys_reboot+0x180/0x25c

Use the irqsave guard, as
commit 33517881ede7 ("irqchip/brcmstb-l2: Use _irqsave locking variants in non-interrupt code")
did for brcmstb-l2.

Fixes: b1479ebb7720 ("irqchip: atmel-aic: Add atmel AIC/AIC5 drivers")
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Assisted-by: LLM
Reviewed-by: Radu Rendec <radu@rendec.net>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260926004124.88221-1-kmehltretter@gmail.com
---
 drivers/irqchip/irq-atmel-aic.c  | 2 +-
 drivers/irqchip/irq-atmel-aic5.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-atmel-aic.c b/drivers/irqchip/irq-atmel-aic.c
index 1dcc52760ecae..4a7935e75e4dd 100644
--- a/drivers/irqchip/irq-atmel-aic.c
+++ b/drivers/irqchip/irq-atmel-aic.c
@@ -123,7 +123,7 @@ static void aic_pm_shutdown(struct irq_data *d)
 {
 	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
 
-	guard(raw_spinlock)(&gc->lock);
+	guard(raw_spinlock_irqsave)(&gc->lock);
 	irq_reg_writel(gc, 0xffffffff, AT91_AIC_IDCR);
 	irq_reg_writel(gc, 0xffffffff, AT91_AIC_ICCR);
 }
diff --git a/drivers/irqchip/irq-atmel-aic5.c b/drivers/irqchip/irq-atmel-aic5.c
index 1f14b401f71d0..07a317ed06ef4 100644
--- a/drivers/irqchip/irq-atmel-aic5.c
+++ b/drivers/irqchip/irq-atmel-aic5.c
@@ -217,7 +217,7 @@ static void aic5_pm_shutdown(struct irq_data *d)
 	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
 	int i;
 
-	guard(raw_spinlock)(&bgc->lock);
+	guard(raw_spinlock_irqsave)(&bgc->lock);
 	for (i = 0; i < dgc->irqs_per_chip; i++) {
 		irq_reg_writel(bgc, i + gc->irq_base, AT91_AIC5_SSR);
 		irq_reg_writel(bgc, 1, AT91_AIC5_IDCR);
-- 
2.53.0