On 02/09/20 at 06:48pm, Baoquan He wrote:
> From: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
>
> When we use SPARSEMEM instead of SPARSEMEM_VMEMMAP, pfn_to_page()
> doesn't work before sparse_init_one_section() is called. This leads to a
> crash when hotplug memory.
>
> PGD 0 P4D 0
> Oops: 0002 [#1] SMP PTI
> CPU: 3 PID: 8 Comm: kworker/u16:0 Tainted: G W 5.5.0-next-20200205+ #339
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015
> Workqueue: kacpi_hotplug acpi_hotplug_work_fn
> RIP: 0010:__memset+0x24/0x30
> Call Trace:
> sparse_add_section+0x150/0x1d8
> __add_pages+0xbf/0x150
> add_pages+0x12/0x60
> add_memory_resource+0xc8/0x210
> ? wake_up_q+0xa0/0xa0
> __add_memory+0x62/0xb0
> acpi_memory_device_add+0x13f/0x300
> acpi_bus_attach+0xf6/0x200
> acpi_bus_scan+0x43/0x90
> acpi_device_hotplug+0x275/0x3d0
> 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
>
> We should use memmap as it did.
>
> Fixes: ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug")
> Signed-off-by: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
> Acked-by: David Hildenbrand <david@xxxxxxxxxx>
> Reviewed-by: Baoquan He <bhe@xxxxxxxxxx>
> CC: Dan Williams <dan.j.williams@xxxxxxxxx>
> Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
Git format-patch added this line of Signed-off-by from me, I will
remove it if repost.
> ---
> mm/sparse.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/sparse.c b/mm/sparse.c
> index a7e78bfe0dce..623755e88255 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -944,7 +944,7 @@ int __meminit sparse_add_section(int nid, unsigned long start_pfn,
> * Poison uninitialized struct pages in order to catch invalid flags
> * combinations.
> */
> - page_init_poison(pfn_to_page(start_pfn), sizeof(struct page) * nr_pages);
> + page_init_poison(memmap, sizeof(struct page) * nr_pages);
>
> ms = __nr_to_section(section_nr);
> set_section_nid(section_nr, nid);
> --
> 2.17.2
>
