• Russ Anderson's avatar
    drivers/base/memory.c: fix show_mem_removable() to handle missing sections · ea35d7d6
    Russ Anderson authored
    commit 21ea9f5ace3a7317cc3ba1fbc749758021a83136 upstream.
    
    "cat /sys/devices/system/memory/memory*/removable" crashed the system.
    
    The problem is that show_mem_removable() is passing a
    bad pfn to is_mem_section_removable(), which causes
    
        if (!node_online(page_to_nid(page)))
    
    to blow up.  Why is it passing in a bad pfn?
    
    The reason is that show_mem_removable() will loop sections_per_block
    times.  sections_per_block is 16, but mem->section_count is 8,
    indicating holes in this memory block.  Checking that the memory section
    is present before checking to see if the memory section is removable
    fixes the problem.
    
       harp5-sys:~ # cat /sys/devices/system/memory/memory*/removable
       0
       1
       1
       1
       1
       1
       1
       1
       1
       1
       1
       1
       1
       1
       BUG: unable to handle kernel paging request at ffffea00c3200000
       IP: [<ffffffff81117ed1>] is_pageblock_removable_nolock+0x1/0x90
       PGD 83ffd4067 PUD 37bdfce067 PMD 0
       Oops: 0000 [#1] SMP
       Modules linked in: autofs4 binfmt_misc rdma_ucm rdma_cm iw_cm ib_addr ib_srp scsi_transport_srp scsi_tgt ib_ipoib ib_cm ib_uverbs ib_umad iw_cxgb3 cxgb3 mdio mlx4_en mlx4_ib ib_sa mlx4_core ib_mthca ib_mad ib_core fuse nls_iso8859_1 nls_cp437 vfat fat joydev loop hid_generic usbhid hid hwperf(O) numatools(O) dm_mod iTCO_wdt ipv6 iTCO_vendor_support igb i2c_i801 ioatdma i2c_algo_bit ehci_pci pcspkr lpc_ich i2c_core ehci_hcd ptp sg mfd_core dca rtc_cmos pps_core mperf button xhci_hcd sd_mod crc_t10dif usbcore usb_common scsi_dh_emc scsi_dh_hp_sw scsi_dh_alua scsi_dh_rdac scsi_dh gru(O) xvma(O) xfs crc32c libcrc32c thermal sata_nv processor piix mptsas mptscsih scsi_transport_sas mptbase megaraid_sas fan thermal_sys hwmon ext3 jbd ata_piix ahci libahci libata scsi_mod
       CPU: 4 PID: 5991 Comm: cat Tainted: G           O 3.11.0-rc5-rja-uv+ #10
       Hardware name: SGI UV2000/ROMLEY, BIOS SGI UV 2000/3000 series BIOS 01/15/2013
       task: ffff88081f034580 ti: ffff880820022000 task.ti: ffff880820022000
       RIP: 0010:[<ffffffff81117ed1>]  [<ffffffff81117ed1>] is_pageblock_removable_nolock+0x1/0x90
       RSP: 0018:ffff880820023df8  EFLAGS: 00010287
       RAX: 0000000000040000 RBX: ffffea00c3200000 RCX: 0000000000000004
       RDX: ffffea00c30b0000 RSI: 00000000001c0000 RDI: ffffea00c3200000
       RBP: ffff880820023e38 R08: 0000000000000000 R09: 0000000000000001
       R10: 0000000000000000 R11: 0000000000000001 R12: ffffea00c33c0000
       R13: 0000160000000000 R14: 6db6db6db6db6db7 R15: 0000000000000001
       FS:  00007ffff7fb2700(0000) GS:ffff88083fc80000(0000) knlGS:0000000000000000
       CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
       CR2: ffffea00c3200000 CR3: 000000081b954000 CR4: 00000000000407e0
       Call Trace:
         show_mem_removable+0x41/0x70
         dev_attr_show+0x2a/0x60
         sysfs_read_file+0xf7/0x1c0
         vfs_read+0xc8/0x130
         SyS_read+0x5d/0xa0
         system_call_fastpath+0x16/0x1b
    Signed-off-by: default avatarRuss Anderson <rja@sgi.com>
    Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
    Cc: Yinghai Lu <yinghai@kernel.org>
    Reviewed-by: default avatarYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    ea35d7d6
memory.c 18.2 KB