• Wei Yang's avatar
    mm/sparsemem: pfn_to_page is not valid yet on SPARSEMEM · 18e19f19
    Wei Yang authored
    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:
    
        BUG: unable to handle page fault for address: 0000000006400000
        #PF: supervisor write access in kernel mode
        #PF: error_code(0x0002) - not-present page
        PGD 0 P4D 0
        Oops: 0002 [#1] SMP PTI
        CPU: 3 PID: 221 Comm: kworker/u16:1 Tainted: G        W         5.5.0-next-20200205+ #343
        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
        Code: cc cc cc cc cc cc 0f 1f 44 00 00 49 89 f9 48 89 d1 83 e2 07 48 c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 <f3> 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 f3
        RSP: 0018:ffffb43ac0373c80 EFLAGS: 00010a87
        RAX: ffffffffffffffff RBX: ffff8a1518800000 RCX: 0000000000050000
        RDX: 0000000000000000 RSI: 00000000000000ff RDI: 0000000006400000
        RBP: 0000000000140000 R08: 0000000000100000 R09: 0000000006400000
        R10: 0000000000000000 R11: 0000000000000002 R12: 0000000000000000
        R13: 0000000000000028 R14: 0000000000000000 R15: ffff8a153ffd9280
        FS:  0000000000000000(0000) GS:ffff8a153ab00000(0000) knlGS:0000000000000000
        CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
        CR2: 0000000006400000 CR3: 0000000136fca000 CR4: 00000000000006e0
        DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
        DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
        Call Trace:
         sparse_add_section+0x1c9/0x26a
         __add_pages+0xbf/0x150
         add_pages+0x12/0x60
         add_memory_resource+0xc8/0x210
         __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
         kthread+0x112/0x130
         ret_from_fork+0x35/0x40
    
    We should use memmap as it did.
    
    On x86 the impact is limited to x86_32 builds, or x86_64 configurations
    that override the default setting for SPARSEMEM_VMEMMAP.
    
    Other memory hotplug archs (arm64, ia64, and ppc) also default to
    SPARSEMEM_VMEMMAP=y.
    
    [dan.j.williams@intel.com: changelog update]
    {rppt@linux.ibm.com: changelog update]
    Link: http://lkml.kernel.org/r/20200219030454.4844-1-bhe@redhat.com
    Fixes: ba72b4c8 ("mm/sparsemem: support sub-section hotplug")
    Signed-off-by: default avatarWei Yang <richardw.yang@linux.intel.com>
    Signed-off-by: default avatarBaoquan He <bhe@redhat.com>
    Acked-by: default avatarDavid Hildenbrand <david@redhat.com>
    Reviewed-by: default avatarBaoquan He <bhe@redhat.com>
    Reviewed-by: default avatarDan Williams <dan.j.williams@intel.com>
    Acked-by: default avatarMichal Hocko <mhocko@suse.com>
    Cc: Mike Rapoport <rppt@linux.ibm.com>
    Cc: Oscar Salvador <osalvador@suse.de>
    Cc: <stable@vger.kernel.org>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    18e19f19
sparse.c 25.5 KB