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 45537926dd2aaa9190ac0fac5a0fbeefcadfea95 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025070622-clay-crimp-7cf6@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 45537926dd2aaa9190ac0fac5a0fbeefcadfea95 Mon Sep 17 00:00:00 2001 From: Niklas Schnelle schnelle@linux.ibm.com Date: Wed, 25 Jun 2025 11:28:28 +0200 Subject: [PATCH] s390/pci: Fix stale function handles in error handling

The error event information for PCI error events contains a function handle for the respective function. This handle is generally captured at the time the error event was recorded. Due to delays in processing or cascading issues, it may happen that during firmware recovery multiple events are generated. When processing these events in order Linux may already have recovered an affected function making the event information stale. Fix this by doing an unconditional CLP List PCI function retrieving the current function handle with the zdev->state_lock held and ignoring the event if its function handle is stale.

Cc: stable@vger.kernel.org Fixes: 4cdf2f4e24ff ("s390/pci: implement minimal PCI error recovery") Reviewed-by: Julian Ruess julianr@linux.ibm.com Reviewed-by: Gerd Bayer gbayer@linux.ibm.com Reviewed-by: Farhan Ali alifm@linux.ibm.com Signed-off-by: Niklas Schnelle schnelle@linux.ibm.com Signed-off-by: Alexander Gordeev agordeev@linux.ibm.com

diff --git a/arch/s390/pci/pci_event.c b/arch/s390/pci/pci_event.c index 2fbee3887d13..82ee2578279a 100644 --- a/arch/s390/pci/pci_event.c +++ b/arch/s390/pci/pci_event.c @@ -273,6 +273,8 @@ static void __zpci_event_error(struct zpci_ccdf_err *ccdf) struct zpci_dev *zdev = get_zdev_by_fid(ccdf->fid); struct pci_dev *pdev = NULL; pci_ers_result_t ers_res; + u32 fh = 0; + int rc;

zpci_dbg(3, "err fid:%x, fh:%x, pec:%x\n", ccdf->fid, ccdf->fh, ccdf->pec); @@ -281,6 +283,15 @@ static void __zpci_event_error(struct zpci_ccdf_err *ccdf)

if (zdev) { mutex_lock(&zdev->state_lock); + rc = clp_refresh_fh(zdev->fid, &fh); + if (rc) + goto no_pdev; + if (!fh || ccdf->fh != fh) { + /* Ignore events with stale handles */ + zpci_dbg(3, "err fid:%x, fh:%x (stale %x)\n", + ccdf->fid, fh, ccdf->fh); + goto no_pdev; + } zpci_update_fh(zdev, ccdf->fh); if (zdev->zbus->bus) pdev = pci_get_slot(zdev->zbus->bus, zdev->devfn);