The patch below does not apply to the 5.15-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-5.15.y git checkout FETCH_HEAD git cherry-pick -x b45873c3f09153d1ad9b3a7bf9e5c0b0387fd2ea # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025110241-repeater-unshackle-ae19@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From b45873c3f09153d1ad9b3a7bf9e5c0b0387fd2ea Mon Sep 17 00:00:00 2001 From: Farhan Ali alifm@linux.ibm.com Date: Wed, 22 Oct 2025 09:47:26 -0700 Subject: [PATCH] s390/pci: Restore IRQ unconditionally for the zPCI device

Commit c1e18c17bda6 ("s390/pci: add zpci_set_irq()/zpci_clear_irq()"), introduced the zpci_set_irq() and zpci_clear_irq(), to be used while resetting a zPCI device.

Commit da995d538d3a ("s390/pci: implement reset_slot for hotplug slot"), mentions zpci_clear_irq() being called in the path for zpci_hot_reset_device(). But that is not the case anymore and these functions are not called outside of this file. Instead zpci_hot_reset_device() relies on zpci_disable_device() also clearing the IRQs, but misses to reset the zdev->irqs_registered flag.

However after a CLP disable/enable reset, the device's IRQ are unregistered, but the flag zdev->irq_registered does not get cleared. It creates an inconsistent state and so arch_restore_msi_irqs() doesn't correctly restore the device's IRQ. This becomes a problem when a PCI driver tries to restore the state of the device through pci_restore_state(). Restore IRQ unconditionally for the device and remove the irq_registered flag as its redundant.

Fixes: c1e18c17bda6 ("s390/pci: add zpci_set_irq()/zpci_clear_irq()") Cc: stable@vger.kernnel.org Reviewed-by: Niklas Schnelle schnelle@linux.ibm.com Reviewed-by: Matthew Rosato mjrosato@linux.ibm.com Signed-off-by: Farhan Ali alifm@linux.ibm.com Signed-off-by: Heiko Carstens hca@linux.ibm.com

diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h index 6890925d5587..a32f465ecf73 100644 --- a/arch/s390/include/asm/pci.h +++ b/arch/s390/include/asm/pci.h @@ -145,7 +145,6 @@ struct zpci_dev { u8 has_resources : 1; u8 is_physfn : 1; u8 util_str_avail : 1; - u8 irqs_registered : 1; u8 tid_avail : 1; u8 rtr_avail : 1; /* Relaxed translation allowed */ unsigned int devfn; /* DEVFN part of the RID*/ diff --git a/arch/s390/pci/pci_irq.c b/arch/s390/pci/pci_irq.c index 84482a921332..e73be96ce5fe 100644 --- a/arch/s390/pci/pci_irq.c +++ b/arch/s390/pci/pci_irq.c @@ -107,9 +107,6 @@ static int zpci_set_irq(struct zpci_dev *zdev) else rc = zpci_set_airq(zdev);

- if (!rc) - zdev->irqs_registered = 1; - return rc; }

@@ -123,9 +120,6 @@ static int zpci_clear_irq(struct zpci_dev *zdev) else rc = zpci_clear_airq(zdev);

- if (!rc) - zdev->irqs_registered = 0; - return rc; }

@@ -427,8 +421,7 @@ bool arch_restore_msi_irqs(struct pci_dev *pdev) { struct zpci_dev *zdev = to_zpci(pdev);

- if (!zdev->irqs_registered) - zpci_set_irq(zdev); + zpci_set_irq(zdev); return true; }