Re: [GIT PULL] Networking for v6.13-rc7

Catalin Marinas
2025-01-20T14:51:17Z

On Sat, Jan 18, 2025 at 01:45:18PM +0000, Catalin Marinas wrote:
> On Thu, Jan 16, 2025 at 07:38:21PM -0800, Jakub Kicinski wrote:
> > After 76d5d4c53e68 ("mm/kmemleak: fix percpu memory leak detection
> > failure") we get this on every instance of our testing VMs:
> >
> > unreferenced object 0x00042aa0 (size 64):
> > comm "swapper/0", pid 0, jiffies 4294667296
> > hex dump (first 32 bytes on cpu 2):
> > 00 00 00 00 00 00 00 00 00 00 06 00 00 00 00 00 ................
> > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> > backtrace (crc 0):
> > pcpu_alloc_noprof+0x4ad/0xab0
> > setup_zone_pageset+0x30/0x290
> > setup_per_cpu_pageset+0x6a/0x1f0
> > start_kernel+0x2a4/0x410
> > x86_64_start_reservations+0x18/0x30
> > x86_64_start_kernel+0xba/0x110
> > common_startup_64+0x12c/0x138
>
> I doubt that's related to the networking pull request but I can see it
> caused by the above commit, now that we track per-cpu allocations. Most
> likely it's a false positive. I'll try to reproduce it next week but
> something like below might fix (untested):
>
> diff --git a/mm/numa.c b/mm/numa.c
> index e2eec07707d1..c594d853cfe8 100644
> --- a/mm/numa.c
> +++ b/mm/numa.c
> @@ -1,5 +1,6 @@
> // SPDX-License-Identifier: GPL-2.0-or-later
>
> +#include <linux/kmemleak.h>
> #include <linux/memblock.h>
> #include <linux/printk.h>
> #include <linux/numa.h>
> @@ -23,6 +24,9 @@ void __init alloc_node_data(int nid)
> nd_size, nid);
> nd = __va(nd_pa);
>
> + /* needed to track related allocation stored in node_data[] */
> + kmemleak_alloc(nd, nd_size, 0, 0);
> +
> /* report and initialize */
> pr_info("NODE_DATA(%d) allocated [mem %#010Lx-%#010Lx]\n", nid,
> nd_pa, nd_pa + nd_size - 1);

Hmm, I don't think this would make any difference as kmemleak does scan
the memblock allocations as long as they have a correspondent VA in the
linear map.

BTW, is NUMA enabled or disabled in your .config?

--
Catalin