5.15-stable review patch. If anyone has any objections, please let me know.

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From: Isaac J. Manjarres isaacmanjarres@google.com

[ Upstream commit 0d6c356dd6547adac2b06b461528e3573f52d953 ]

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 Reviewed-by: Mike Rapoport (Microsoft) rppt@kernel.org Reviewed-by: David Hildenbrand david@redhat.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org (cherry picked from commit 0d6c356dd6547adac2b06b461528e3573f52d953) Signed-off-by: Mike Rapoport (Microsoft) rppt@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- mm/page_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 63e131dc2b43e..0a5e9a4b923cb 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -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)