From: Justin He <Justin.He@arm.com>
To: David Hildenbrand <david@redhat.com>
Cc: Baoquan He <bhe@redhat.com>, Kaly Xin <Kaly.Xin@arm.com>,
Catalin Marinas <Catalin.Marinas@arm.com>,
Chuhong Yuan <hslester96@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Mike Rapoport <rppt@linux.ibm.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Will Deacon <will@kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: RE: [PATCH 2/3] mm/memory_hotplug: harden try_offline_node against bogus nid
Date: Mon, 6 Jul 2020 13:45:13 +0000 [thread overview]
Message-ID: <AM6PR08MB40697FCA7F2374EBE6459FE4F7690@AM6PR08MB4069.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <4b864877-1147-8336-5e9a-e89ac5c99be3@redhat.com>
Hi David
> -----Original Message-----
> From: David Hildenbrand <david@redhat.com>
> Sent: Monday, July 6, 2020 3:58 PM
> To: Justin He <Justin.He@arm.com>; Catalin Marinas
> <Catalin.Marinas@arm.com>; Will Deacon <will@kernel.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>; Mike Rapoport
> <rppt@linux.ibm.com>; Baoquan He <bhe@redhat.com>; Chuhong Yuan
> <hslester96@gmail.com>; linux-arm-kernel@lists.infradead.org; linux-
> kernel@vger.kernel.org; linux-mm@kvack.org; Kaly Xin <Kaly.Xin@arm.com>
> Subject: Re: [PATCH 2/3] mm/memory_hotplug: harden try_offline_node
> against bogus nid
>
> On 06.07.20 03:19, Jia He wrote:
> > When testing the remove_memory path of dax pmem, there will be a panic
> with
> > call trace:
> > try_remove_memory+0x84/0x170
> > remove_memory+0x38/0x58
> > dev_dax_kmem_remove+0x3c/0x84 [kmem]
> > device_release_driver_internal+0xfc/0x1c8
> > device_release_driver+0x28/0x38
> > bus_remove_device+0xd4/0x158
> > device_del+0x160/0x3a0
> > unregister_dev_dax+0x30/0x68
> > devm_action_release+0x20/0x30
> > release_nodes+0x150/0x240
> > devres_release_all+0x6c/0x1d0
> > device_release_driver_internal+0x10c/0x1c8
> > driver_detach+0xac/0x170
> > bus_remove_driver+0x64/0x130
> > driver_unregister+0x34/0x60
> > dax_pmem_exit+0x14/0xffc4 [dax_pmem]
> > __arm64_sys_delete_module+0x18c/0x2d0
> > el0_svc_common.constprop.2+0x78/0x168
> > do_el0_svc+0x34/0xa0
> > el0_sync_handler+0xe0/0x188
> > el0_sync+0x164/0x180
> >
> > It is caused by the bogus nid (-1). Although the root cause is pmem dax
> > translates from pxm to node_id incorrectly due to numa_off, it is worth
> > hardening the codes in try_offline_node(), quiting if !pgdat.
> >
> > Signed-off-by: Jia He <justin.he@arm.com>
> > ---
> > mm/memory_hotplug.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> > index da374cd3d45b..e1e290577b45 100644
> > --- a/mm/memory_hotplug.c
> > +++ b/mm/memory_hotplug.c
> > @@ -1680,6 +1680,9 @@ void try_offline_node(int nid)
> > pg_data_t *pgdat = NODE_DATA(nid);
> > int rc;
> >
> > + if (WARN_ON(!pgdat))
> > + return;
> > +
> > /*
> > * If the node still spans pages (especially ZONE_DEVICE), don't
> > * offline it. A node spans memory after move_pfn_range_to_zone(),
> >
>
> Hm. If I am not wrong, somebody used add_memory() with another nid than
> try_remove_memory()?
>
Yes after commit fa6d9ec790550, it can prevent this possibility.
I will drop this single patch. Thanks
--
Cheers,
Justin (Jia He)
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-07-06 13:47 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-06 1:19 [PATCH 0/3] Fix and enable pmem as RAM on arm64 Jia He
2020-07-06 1:19 ` [PATCH 1/3] arm64/numa: set numa_off to false when numa node is fake Jia He
2020-07-06 8:02 ` David Hildenbrand
2020-07-06 12:36 ` Justin He
2020-07-06 13:56 ` David Hildenbrand
2020-07-06 10:29 ` Jonathan Cameron
2020-07-06 10:46 ` Jonathan Cameron
2020-07-06 12:47 ` Justin He
2020-07-06 13:03 ` Jonathan Cameron
2020-07-06 1:19 ` [PATCH 2/3] mm/memory_hotplug: harden try_offline_node against bogus nid Jia He
2020-07-06 7:57 ` David Hildenbrand
2020-07-06 13:45 ` Justin He [this message]
2020-07-06 1:19 ` [PATCH 3/3] mm/memory_hotplug: fix unpaired mem_hotplug_begin/done Jia He
2020-07-06 7:49 ` David Hildenbrand
2020-07-07 22:10 ` Dan Williams
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=AM6PR08MB40697FCA7F2374EBE6459FE4F7690@AM6PR08MB4069.eurprd08.prod.outlook.com \
--to=justin.he@arm.com \
--cc=Catalin.Marinas@arm.com \
--cc=Kaly.Xin@arm.com \
--cc=akpm@linux-foundation.org \
--cc=bhe@redhat.com \
--cc=david@redhat.com \
--cc=hslester96@gmail.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=rppt@linux.ibm.com \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).