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* [merged mm-hotfixes-stable] resource-fix-false-warning-in-__request_region.patch removed from -mm tree
@ 2025-07-25  0:58 Andrew Morton
  0 siblings, 0 replies; only message in thread
From: Andrew Morton @ 2025-07-25  0:58 UTC (permalink / raw)
  To: mm-commits, stable, dan.j.williams, akinobu.mita, akpm


The quilt patch titled
     Subject: resource: fix false warning in __request_region()
has been removed from the -mm tree.  Its filename was
     resource-fix-false-warning-in-__request_region.patch

This patch was dropped because it was merged into the mm-hotfixes-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Akinobu Mita <akinobu.mita@gmail.com>
Subject: resource: fix false warning in __request_region()
Date: Sat, 19 Jul 2025 20:26:04 +0900

A warning is raised when __request_region() detects a conflict with a
resource whose resource.desc is IORES_DESC_DEVICE_PRIVATE_MEMORY.

But this warning is only valid for iomem_resources.
The hmem device resource uses resource.desc as the numa node id, which can
cause spurious warnings.

This warning appeared on a machine with multiple cxl memory expanders. 
One of the NUMA node id is 6, which is the same as the value of
IORES_DESC_DEVICE_PRIVATE_MEMORY.

In this environment it was just a spurious warning, but when I saw the
warning I suspected a real problem so it's better to fix it.

This change fixes this by restricting the warning to only iomem_resource.
This also adds a missing new line to the warning message.

Link: https://lkml.kernel.org/r/20250719112604.25500-1-akinobu.mita@gmail.com
Fixes: 7dab174e2e27 ("dax/hmem: Move hmem device registration to dax_hmem.ko")
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 kernel/resource.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/kernel/resource.c~resource-fix-false-warning-in-__request_region
+++ a/kernel/resource.c
@@ -1279,8 +1279,9 @@ static int __request_region_locked(struc
 		 * become unavailable to other users.  Conflicts are
 		 * not expected.  Warn to aid debugging if encountered.
 		 */
-		if (conflict->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) {
-			pr_warn("Unaddressable device %s %pR conflicts with %pR",
+		if (parent == &iomem_resource &&
+		    conflict->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) {
+			pr_warn("Unaddressable device %s %pR conflicts with %pR\n",
 				conflict->name, conflict, res);
 		}
 		if (conflict != parent) {
_

Patches currently in -mm which might be from akinobu.mita@gmail.com are



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