Commits
Matt Fleming committed 09503379dc9
x86/efi: Check status field to validate BGRT header Madper reported seeing the following crash, BUG: unable to handle kernel paging request at ffffffffff340003 IP: [<ffffffff81d85ba4>] efi_bgrt_init+0x9d/0x133 Call Trace: [<ffffffff81d8525d>] efi_late_init+0x9/0xb [<ffffffff81d68f59>] start_kernel+0x436/0x450 [<ffffffff81d6892c>] ? repair_env_string+0x5c/0x5c [<ffffffff81d68120>] ? early_idt_handlers+0x120/0x120 [<ffffffff81d685de>] x86_64_start_reservations+0x2a/0x2c [<ffffffff81d6871e>] x86_64_start_kernel+0x13e/0x14d This is caused because the layout of the ACPI BGRT header on this system doesn't match the definition from the ACPI spec, and so we get a bogus physical address when dereferencing ->image_address in efi_bgrt_init(). Luckily the status field in the BGRT header clearly marks it as invalid, so we can check that field and skip BGRT initialisation. Reported-by: Madper Xie <cxie@redhat.com> Suggested-by: Toshi Kani <toshi.kani@hp.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Matt Fleming <matt.fleming@intel.com>