Re: [Patch V2 2/2] x86/mm/numa: remove the numa_nodemask_from_meminfo()

From: Borislav Petkov <bp@alien8.de>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Wei Yang <richard.weiyang@gmail.com>,
	tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com,
	tj@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [Patch V2 2/2] x86/mm/numa: remove the numa_nodemask_from_meminfo()
Date: Thu, 6 Apr 2017 16:59:37 +0200	[thread overview]
Message-ID: <20170406145937.docce7sa5tuqyon4@pd.tnic> (raw)
In-Reply-To: <20170406124459.dwn5zhpr2xqg3lqm@node.shutemov.name>

On Thu, Apr 06, 2017 at 03:44:59PM +0300, Kirill A. Shutemov wrote:
> I've got the crash below on master/tip. Reveting the patch helps.
> 
> ================================================================================
> UBSAN: Undefined behaviour in /home/kas/linux/la57/mm/sparse.c:336:9
> member access within null pointer of type 'struct pglist_data'
> CPU: 0 PID: 0 Comm: swapper Not tainted 4.11.0-rc5-00604-gf03eaf0479bc #5084
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015

Oh, qemu, how do you trigger this exactly? .config and qemu cmdline pls?

Alternatively, can you run this debug diff and give me the output?

I'd like to know what is happening and how did I miss that during
review.

Thanks.

---



Oh, qemu, how do you trigger this exactly? .config and qemu cmdline pls?

Alternatively, can you run this debug diff and give me the output?

I'd like to know what is happening and how did I miss that during review.

Thanks.

---

diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index 29bfcb42c4f5..e20101fed1d9 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -517,11 +517,19 @@ static int __init numa_register_memblks(struct numa_meminfo *mi)
 
 	/* Account for nodes with cpus and no memory */
 	node_possible_map = numa_nodes_parsed;
+
+	pr_info("%s: numa_nodes_parsed: %*pbl\n",
+		__func__, nodemask_pr_args(&numa_nodes_parsed));
+
 	if (WARN_ON(nodes_empty(node_possible_map)))
 		return -EINVAL;
 
 	for (i = 0; i < mi->nr_blks; i++) {
 		struct numa_memblk *mb = &mi->blk[i];
+
+		if (mb->nid != NUMA_NO_NODE)
+			pr_info("%s: nid: %d\n", __func__, mb->nid);
+
 		memblock_set_node(mb->start, mb->end - mb->start,
 				  &memblock.memory, mb->nid);
 	}
diff --git a/mm/sparse.c b/mm/sparse.c
index db6bf3c97ea2..1f4cb635a111 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -333,6 +333,7 @@ static unsigned long * __init
 sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
 					 unsigned long size)
 {
+	pr_info("%s: node_id: %d\n", __func__, pgdat->node_id);
 	return memblock_virt_alloc_node_nopanic(size, pgdat->node_id);
 }
 

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.
