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由 Dave Young 提交于
Maniaxx reported a kernel boot crash in the EFI code, which I emulated by using same invalid phys addr in code: BUG: unable to handle kernel paging request at ffffffffff280001 IP: efi_bgrt_init+0xfb/0x153 ... Call Trace: ? bgrt_init+0xbc/0xbc acpi_parse_bgrt+0xe/0x12 acpi_table_parse+0x89/0xb8 acpi_boot_init+0x445/0x4e2 ? acpi_parse_x2apic+0x79/0x79 ? dmi_ignore_irq0_timer_override+0x33/0x33 setup_arch+0xb63/0xc82 ? early_idt_handler_array+0x120/0x120 start_kernel+0xb7/0x443 ? early_idt_handler_array+0x120/0x120 x86_64_start_reservations+0x29/0x2b x86_64_start_kernel+0x154/0x177 secondary_startup_64+0x9f/0x9f There is also a similar bug filed in bugzilla.kernel.org: https://bugzilla.kernel.org/show_bug.cgi?id=195633 The crash is caused by this commit: 7b0a9114 efi/x86: Move the EFI BGRT init code to early init code The root cause is the firmware on those machines provides invalid BGRT image addresses. In a kernel before above commit BGRT initializes late and uses ioremap() to map the image address. Ioremap validates the address, if it is not a valid physical address ioremap() just fails and returns. However in current kernel EFI BGRT initializes early and uses early_memremap() which does not validate the image address, and kernel panic happens. According to ACPI spec the BGRT image address should fall into EFI_BOOT_SERVICES_DATA, see the section 5.2.22.4 of below document: http://www.uefi.org/sites/default/files/resources/ACPI_6_1.pdf Fix this issue by validating the image address in efi_bgrt_init(). If the image address does not fall into any EFI_BOOT_SERVICES_DATA areas we just bail out with a warning message. Reported-by: NManiaxx <tripleshiftone@gmail.com> Signed-off-by: NDave Young <dyoung@redhat.com> Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Fixes: 7b0a9114 ("efi/x86: Move the EFI BGRT init code to early init code") Link: http://lkml.kernel.org/r/20170609084558.26766-2-ard.biesheuvel@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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