From: David Hildenbrand <david@redhat.com>
To: Baoquan He <bhe@redhat.com>, linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, akpm@linux-foundation.org, mhocko@suse.com,
richardw.yang@linux.intel.com, dan.j.williams@intel.com,
osalvador@suse.de, rppt@linux.ibm.com
Subject: Re: [PATCH v3 1/7] mm/hotplug: fix hot remove failure in SPARSEMEM|!VMEMMAP case
Date: Mon, 9 Mar 2020 09:58:29 +0100 [thread overview]
Message-ID: <b0ff37b3-bae1-bdd6-8a4f-62f03e028839@redhat.com> (raw)
In-Reply-To: <20200307084229.28251-2-bhe@redhat.com>
On 07.03.20 09:42, Baoquan He wrote:
> In section_deactivate(), pfn_to_page() doesn't work any more after
> ms->section_mem_map is resetting to NULL in SPARSEMEM|!VMEMMAP case.
> It caused hot remove failure:
>
> kernel BUG at mm/page_alloc.c:4806!
> invalid opcode: 0000 [#1] SMP PTI
> CPU: 3 PID: 8 Comm: kworker/u16:0 Tainted: G W 5.5.0-next-20200205+ #340
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015
> Workqueue: kacpi_hotplug acpi_hotplug_work_fn
> RIP: 0010:free_pages+0x85/0xa0
> Call Trace:
> __remove_pages+0x99/0xc0
> arch_remove_memory+0x23/0x4d
> try_remove_memory+0xc8/0x130
> ? walk_memory_blocks+0x72/0xa0
> __remove_memory+0xa/0x11
> acpi_memory_device_remove+0x72/0x100
> acpi_bus_trim+0x55/0x90
> acpi_device_hotplug+0x2eb/0x3d0
> acpi_hotplug_work_fn+0x1a/0x30
> process_one_work+0x1a7/0x370
> worker_thread+0x30/0x380
> ? flush_rcu_work+0x30/0x30
> kthread+0x112/0x130
> ? kthread_create_on_node+0x60/0x60
> ret_from_fork+0x35/0x40
>
> Let's move the ->section_mem_map resetting after depopulate_section_memmap()
> to fix it.
>
> Fixes: ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug")
> Signed-off-by: Baoquan He <bhe@redhat.com>
> Cc: stable@vger.kernel.org
> ---
> mm/sparse.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/mm/sparse.c b/mm/sparse.c
> index 42c18a38ffaa..1b50c15677d7 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -734,6 +734,7 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
> struct mem_section *ms = __pfn_to_section(pfn);
> bool section_is_early = early_section(ms);
> struct page *memmap = NULL;
> + bool empty = false;
Oh, one NIT: no need to initialize empty to false.
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2020-03-09 8:58 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-07 8:42 [PATCH v3 0/7] mm/hotplug: Only use subsection map for VMEMMAP Baoquan He
2020-03-07 8:42 ` [PATCH v3 1/7] mm/hotplug: fix hot remove failure in SPARSEMEM|!VMEMMAP case Baoquan He
2020-03-07 20:59 ` Andrew Morton
2020-03-07 22:55 ` Baoquan He
2020-03-09 8:56 ` David Hildenbrand
2020-03-09 8:58 ` David Hildenbrand [this message]
2020-03-09 13:18 ` Baoquan He
2020-03-09 13:22 ` David Hildenbrand
2020-03-09 10:13 ` Pankaj Gupta
2020-03-09 10:13 ` Pankaj Gupta
2020-03-09 12:56 ` Michal Hocko
2020-03-07 8:42 ` [PATCH v3 2/7] mm/sparse.c: introduce new function fill_subsection_map() Baoquan He
2020-03-07 8:42 ` [PATCH v3 3/7] mm/sparse.c: introduce a new function clear_subsection_map() Baoquan He
2020-03-09 8:59 ` David Hildenbrand
2020-03-09 13:32 ` Baoquan He
2020-03-09 13:38 ` David Hildenbrand
2020-03-09 14:07 ` Baoquan He
2020-03-07 8:42 ` [PATCH v3 4/7] mm/sparse.c: only use subsection map in VMEMMAP case Baoquan He
2020-03-09 9:00 ` David Hildenbrand
2020-03-07 8:42 ` [PATCH v3 5/7] mm/sparse.c: add note about only VMEMMAP supporting sub-section support Baoquan He
2020-03-07 11:55 ` Baoquan He
2020-03-10 14:46 ` Michal Hocko
2020-03-11 4:20 ` Baoquan He
2020-03-07 8:42 ` [PATCH v3 6/7] mm/sparse.c: move subsection_map related codes together Baoquan He
2020-03-09 9:08 ` David Hildenbrand
2020-03-09 13:41 ` Baoquan He
2020-03-07 8:42 ` [PATCH v3 7/7] mm/sparse.c: Use __get_free_pages() instead in populate_section_memmap() Baoquan He
2020-03-10 14:56 ` Michal Hocko
2020-03-10 14:59 ` David Hildenbrand
2020-03-11 9:31 ` Baoquan He
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