FAILED: patch "[PATCH] iommufd: Fix wrong hwpt passed to" failed to apply to 6.12-stable tree

The patch below does not apply to the 6.12-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 <[email protected]>.

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-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x ba5c0f28a26e7d9be1e0997f8920dd638e2782fd
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026080517-fiscally-lily-170a@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

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

From ba5c0f28a26e7d9be1e0997f8920dd638e2782fd Mon Sep 17 00:00:00 2001
From: Peiyang He <[email protected]>
Date: Fri, 10 Jul 2026 20:29:52 +0800
Subject: [PATCH] iommufd: Fix wrong hwpt passed to
 iommufd_auto_response_faults on replace

iommufd_hwpt_replace_device() calls:

	iommufd_auto_response_faults(hwpt, old_handle);

passing the *new* hwpt together with the handle of
the device's *old* domain. This should be a parameter mismatch:

1. Semantically, iommufd_auto_response_faults(x, handle) scans
   x->fault's deliver list and response xarray for groups matching
   "handle". A group is queued under the hwpt that was attached at
   fault-delivery time. old_handle is fetched *before* the domain switch,
   so its group lives on old->fault, not on the new hwpt->fault.

2. Historically, the first argument was "old". The routine was
   introduced by commit b7d8833677ba ("iommufd: Fault-capable hwpt
   attach/detach/replace") as __fault_domain_replace_dev() in
   fault.c, correctly calling iommufd_auto_response_faults(old, curr).
   Commit fb21b1568ada ("iommufd: Make attach_handle generic than
   fault specific") moved this into iommufd_hwpt_replace_device() in
   device.c and swapped it to "hwpt". This should be a refactor regression,
   not an intentional change.

Fix this by passing "old" instead.

Link: https://patch.msgid.link/r/9D652384339C69D5+20260710122952.885325-1-peiyang_he@smail.nju.edu.cn
Fixes: fb21b1568ada ("iommufd: Make attach_handle generic than fault specific")
Cc: [email protected]
Signed-off-by: Peiyang He <[email protected]>
Reviewed-by: Kevin Tian <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 170a7005f0bc..2895e5370910 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -589,7 +589,7 @@ static int iommufd_hwpt_replace_device(struct iommufd_device *idev,
 	if (rc)
 		goto out_free_handle;
 
-	iommufd_auto_response_faults(hwpt, old_handle);
+	iommufd_auto_response_faults(old, old_handle);
 	kfree(old_handle);
 
 	return 0;