FAILED: patch "[PATCH] s390/pci: Add error cleanup in zpci_directed_irq_init()" failed to apply to 6.18-stable tree

[Sasha Levin <sashal@kernel.org>]

The patch below does not apply to the 6.18-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-6.18.y
git checkout FETCH_HEAD
git cherry-pick -x 769f66f595c11185c66913ea5d96420504bfebc3
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107051105-failed-6.18-769f66f595c1@kernel.org' --subject-prefix 'PATCH 6.18.y' 'HEAD^..'

Thanks,
Sasha

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

From 769f66f595c11185c66913ea5d96420504bfebc3 Mon Sep 17 00:00:00 2001
From: Tobias Schumacher <ts@linux.ibm.com>
Date: Fri, 9 Oct 2026 08:15:52 +0200
Subject: [PATCH] s390/pci: Add error cleanup in zpci_directed_irq_init()

If per-CPU airq_iv allocation fails in the loop, previously allocated
vectors and arrays leak. Add proper error path to release all resources
on failure.

The error path frees zpci_sbv, but SIC_IRQ_MODE_DIRECT has already
programmed its address into the hardware. Set the directed interrupt
mode only after all allocations have succeeded, so a failed init leaves
no freed memory registered with the hardware.

Fixes: e979ce7bced2 ("s390/pci: provide support for CPU directed interrupts")
Cc: stable@vger.kernel.org
Signed-off-by: Tobias Schumacher <ts@linux.ibm.com>
Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
---
 arch/s390/pci/pci_irq.c | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/arch/s390/pci/pci_irq.c b/arch/s390/pci/pci_irq.c
index c5fabad381395..bcf11585df8d8 100644
--- a/arch/s390/pci/pci_irq.c
+++ b/arch/s390/pci/pci_irq.c
@@ -569,14 +569,9 @@ static int __init zpci_directed_irq_init(void)
 	if (!zpci_sbv)
 		return -ENOMEM;
 
-	iib.diib.isc = PCI_ISC;
-	iib.diib.nr_cpus = num_possible_cpus();
-	iib.diib.disb_addr = virt_to_phys(zpci_sbv->vector);
-	zpci_set_irq_ctrl(SIC_IRQ_MODE_DIRECT, 0, &iib);
-
 	zpci_dibv = kzalloc_objs(*zpci_dibv, num_possible_cpus());
 	if (!zpci_dibv)
-		return -ENOMEM;
+		goto out_free_sbv;
 
 	for_each_possible_cpu(cpu) {
 		/*
@@ -589,13 +584,30 @@ static int __init zpci_directed_irq_init(void)
 						AIRQ_IV_CACHELINE |
 						(!cpu ? AIRQ_IV_ALLOC : 0), NULL);
 		if (!zpci_dibv[cpu])
-			return -ENOMEM;
+			goto out_free_dibv;
 	}
+
+	iib.diib.isc = PCI_ISC;
+	iib.diib.nr_cpus = num_possible_cpus();
+	iib.diib.disb_addr = virt_to_phys(zpci_sbv->vector);
+	zpci_set_irq_ctrl(SIC_IRQ_MODE_DIRECT, 0, &iib);
 	on_each_cpu(cpu_enable_directed_irq, NULL, 1);
 
 	zpci_irq_chip.irq_set_affinity = zpci_set_irq_affinity;
 
 	return 0;
+
+out_free_dibv:
+	for_each_possible_cpu(cpu) {
+		if (zpci_dibv[cpu])
+			airq_iv_release(zpci_dibv[cpu]);
+	}
+	kfree(zpci_dibv);
+	zpci_dibv = NULL;
+out_free_sbv:
+	airq_iv_release(zpci_sbv);
+	zpci_sbv = NULL;
+	return -ENOMEM;
 }
 
 static int __init zpci_floating_irq_init(void)
-- 
2.53.0