+ mm-mm_init-fix-hash-table-order-logging-in-alloc_large_system_hash.patch added to mm-hotfixes-unstable branch

+ mm-mm_init-fix-hash-table-order-logging-in-alloc_large_system_hash.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm/mm_init: fix hash table order logging in alloc_large_system_hash()
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     mm-mm_init-fix-hash-table-order-logging-in-alloc_large_system_hash.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mm_init-fix-hash-table-order-logging-in-alloc_large_system_hash.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: "Isaac J. Manjarres" <isaacmanjarres@google.com>
Subject: mm/mm_init: fix hash table order logging in alloc_large_system_hash()
Date: Tue, 28 Oct 2025 12:10:12 -0700

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)

Link: https://lkml.kernel.org/r/20251028191020.413002-1-isaacmanjarres@google.com
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Isaac J. Manjarres <isaacmanjarres@google.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

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

--- a/mm/mm_init.c~mm-mm_init-fix-hash-table-order-logging-in-alloc_large_system_hash
+++ a/mm/mm_init.c
@@ -2469,7 +2469,7 @@ void *__init alloc_large_system_hash(con
 		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)
_

Patches currently in -mm which might be from isaacmanjarres@google.com are

mm-mm_init-fix-hash-table-order-logging-in-alloc_large_system_hash.patch