| From d41e2f3bd54699f85b3d6f45abd09fa24a222cb9 Mon Sep 17 00:00:00 2001 |
| From: Baoquan He <bhe@redhat.com> |
| Date: Sat, 21 Mar 2020 18:22:13 -0700 |
| Subject: mm/hotplug: fix hot remove failure in SPARSEMEM|!VMEMMAP case |
| |
| From: Baoquan He <bhe@redhat.com> |
| |
| commit d41e2f3bd54699f85b3d6f45abd09fa24a222cb9 upstream. |
| |
| 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 |
| causes a 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 |
| __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 |
| kthread+0x112/0x130 |
| ret_from_fork+0x35/0x40 |
| |
| Let's move the ->section_mem_map resetting after |
| depopulate_section_memmap() to fix it. |
| |
| [akpm@linux-foundation.org: remove unneeded initialization, per David] |
| Fixes: ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug") |
| Signed-off-by: Baoquan He <bhe@redhat.com> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> |
| Reviewed-by: David Hildenbrand <david@redhat.com> |
| Acked-by: Michal Hocko <mhocko@suse.com> |
| Cc: Wei Yang <richardw.yang@linux.intel.com> |
| Cc: Oscar Salvador <osalvador@suse.de> |
| Cc: Mike Rapoport <rppt@linux.ibm.com> |
| Cc: <stable@vger.kernel.org> |
| Link: http://lkml.kernel.org/r/20200307084229.28251-2-bhe@redhat.com |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| mm/sparse.c | 8 ++++++-- |
| 1 file changed, 6 insertions(+), 2 deletions(-) |
| |
| --- a/mm/sparse.c |
| +++ b/mm/sparse.c |
| @@ -744,6 +744,7 @@ static void section_deactivate(unsigned |
| struct mem_section *ms = __pfn_to_section(pfn); |
| bool section_is_early = early_section(ms); |
| struct page *memmap = NULL; |
| + bool empty; |
| unsigned long *subsection_map = ms->usage |
| ? &ms->usage->subsection_map[0] : NULL; |
| |
| @@ -774,7 +775,8 @@ static void section_deactivate(unsigned |
| * For 2/ and 3/ the SPARSEMEM_VMEMMAP={y,n} cases are unified |
| */ |
| bitmap_xor(subsection_map, map, subsection_map, SUBSECTIONS_PER_SECTION); |
| - if (bitmap_empty(subsection_map, SUBSECTIONS_PER_SECTION)) { |
| + empty = bitmap_empty(subsection_map, SUBSECTIONS_PER_SECTION); |
| + if (empty) { |
| unsigned long section_nr = pfn_to_section_nr(pfn); |
| |
| /* |
| @@ -789,13 +791,15 @@ static void section_deactivate(unsigned |
| ms->usage = NULL; |
| } |
| memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr); |
| - ms->section_mem_map = (unsigned long)NULL; |
| } |
| |
| if (section_is_early && memmap) |
| free_map_bootmem(memmap); |
| else |
| depopulate_section_memmap(pfn, nr_pages, altmap); |
| + |
| + if (empty) |
| + ms->section_mem_map = (unsigned long)NULL; |
| } |
| |
| static struct page * __meminit section_activate(int nid, unsigned long pfn, |
