• Parag Warudkar's avatar
    x86: fix DMI out of memory problems · 79da4721
    Parag Warudkar authored
    
    
    People with HP Desktops (including me) encounter couple of DMI errors
    during boot - dmi_save_oem_strings_devices: out of memory and
    dmi_string: out of memory.
    
    On some HP desktops the DMI data include OEM strings (type 11) out of
    which only few are meaningful and most other are empty. DMI code
    religiously creates copies of these 27 strings (65 bytes each in my
    case) and goes OOM in dmi_string().
    
    If DMI_MAX_DATA is bumped up a little then it goes and fails in
    dmi_save_oem_strings while allocating dmi_devices of sizeof(struct
    dmi_device) corresponding to these strings.
    
    On x86_64 since we cannot use alloc_bootmem this early, the code uses a
    static array of 2048 bytes (DMI_MAX_DATA) for allocating the memory DMI
    needs. It does not survive the creation of empty strings and devices.
    
    Fix this by detecting and not newly allocating empty strings and instead
    using a one statically defined dmi_empty_string.
    
    Also do not create a new struct dmi_device for each empty string - use
    one statically define dmi_device with .name=dmi_empty_string and add
    that to the dmi_devices list.
    
    On x64 this should stop the OOM with same current size of DMI_MAX_DATA
    and on x86 this should save a good amount of (27*65 bytes +
    27*sizeof(struct dmi_device) bootmem.
    
    Compile and boot tested on both 32-bit and 64-bit x86.
    Signed-off-by: default avatarParag Warudkar <parag.warudkar@gmail.com>
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    79da4721
dmi_scan.c 11.3 KB