On 03/07/20 at 12:59pm, Andrew Morton wrote: > On Sat, 7 Mar 2020 16:42:23 +0800 Baoquan He <bhe@xxxxxxxxxx> 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. > > Thanks. I think I'll cherrypick this fix and shall await more > review/testing input on the rest of the series. Sure, thanks.
