FAILED: patch "[PATCH] mm/mm_init: fix hash table order logging in" failed to apply to 5.15-stable tree

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 <[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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 0d6c356dd6547adac2b06b461528e3573f52d953
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2025112033-overstep-denim-0e6a@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 0d6c356dd6547adac2b06b461528e3573f52d953 Mon Sep 17 00:00:00 2001
From: "Isaac J. Manjarres" <[email protected]>
Date: Tue, 28 Oct 2025 12:10:12 -0700
Subject: [PATCH] mm/mm_init: fix hash table order logging in
alloc_large_system_hash()

When emitting the order of the allocation for a hash table, alloc_large_system_hash() unconditionally subtracts PAGE_SHIFT from log base 2 of the allocation size. This is not correct if the allocation size is smaller than a page, and yields a negative value for the order as seen below:

TCP established hash table entries: 32 (order: -4, 256 bytes, linear) TCP bind hash table entries: 32 (order: -2, 1024 bytes, linear)

Use get_order() to compute the order when emitting the hash table information to correctly handle cases where the allocation size is smaller than a page:

TCP established hash table entries: 32 (order: 0, 256 bytes, linear) TCP bind hash table entries: 32 (order: 0, 1024 bytes, linear)

index 3db2dea7db4c..7712d887b696 100644
@@ -2469,7 +2469,7 @@ void *__init alloc_large_system_hash(const char *tablename,
 		panic("Failed to allocate %s hash table\n", tablename);
 
 	pr_info("%s hash table entries: %ld (order: %d, %lu bytes, %s)\n",
-		tablename, 1UL << log2qty, ilog2(size) - PAGE_SHIFT, size,
+		tablename, 1UL << log2qty, get_order(size), size,
 		virt ? (huge ? "vmalloc hugepage" : "vmalloc") : "linear");
 
 	if (_hash_shift)

From: "Isaac J. Manjarres" <[email protected]>

When emitting the order of the allocation for a hash table, alloc_large_system_hash() unconditionally subtracts PAGE_SHIFT from log base 2 of the allocation size. This is not correct if the allocation size is smaller than a page, and yields a negative value for the order as seen below:

TCP established hash table entries: 32 (order: -4, 256 bytes, linear) TCP bind hash table entries: 32 (order: -2, 1024 bytes, linear)

Use get_order() to compute the order when emitting the hash table information to correctly handle cases where the allocation size is smaller than a page:

TCP established hash table entries: 32 (order: 0, 256 bytes, linear) TCP bind hash table entries: 32 (order: 0, 1024 bytes, linear)

---
 mm/page_alloc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 63e131dc2b43..0a5e9a4b923c 100644
@@ -8921,7 +8921,7 @@ void *__init alloc_large_system_hash(const char *tablename,
 		panic("Failed to allocate %s hash table\n", tablename);
 
 	pr_info("%s hash table entries: %ld (order: %d, %lu bytes, %s)\n",
-		tablename, 1UL << log2qty, ilog2(size) - PAGE_SHIFT, size,
+		tablename, 1UL << log2qty, get_order(size), size,
 		virt ? (huge ? "vmalloc hugepage" : "vmalloc") : "linear");
 
 	if (_hash_shift)

2.50.1

This patch has been queued up for the 5.15 stable tree.

Subject: mm/mm_init: fix hash table order logging in alloc_large_system_hash()
Queue: 5.15

Thanks for the backport!