On 8 June 2017 at 05:32, Dave Young <dyoung@xxxxxxxxxx> wrote: > Maniaxx <tripleshiftone@xxxxxxxxx> reported kernel boot panic similar to below: > (emulated the panic with using same invalid phys addr in a uefi vm) > There are also a bug in bugzilla.kernel.org: > https://bugzilla.kernel.org/show_bug.cgi?id=195633 > > This happens after below commit: > 7b0a911 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. > > With original efi bgrt code we initialize bgrt late > and use ioremap to map the image address. In ioremap code we check the > address is a valid physical address or not before really map it. > > With current new efi bgrt code we moved the initialization to early code > so we switch to early_memremap which does not check the phys_addr like > ioremap does. This lead to the early kernel panics. > > Fix this by checking the image physical address, if it is not within > any EFI_BOOT_SERVICES_DATA areas then we just bail out. It is stronger > then the original ioremap checking, according to spec the BGRT data > should fall into EFI_BOOT_SERVICES_DATA. > Which spec? The UEFI spec does not mention BGRT, and given that it is an ACPI table, I would expect an ACPI reclaim region to be the most appropriate. A quick test with QEMU confirms this: ACPI: BGRT 0x000000013A5E0000 000038 (v01 INTEL EDK2 00000002 01000013) and efi: 0x00013a5e0000-0x00013a5effff [ACPI Reclaim Memory| | | | | | | | |WB| | | ] So while I agree that we have to fix this, and that checking the BGRT address against the UEFI memory map is the most appropriate course of action, requiring a certain region type is probably not what we want. We have a similar check for ESRT, in efi_mem_desc_lookup(), which looks a bit dodgy tbh, given that it allows any region type (including MMIO), as long as it has the EFI_MEMORY_RUNTIME attribute, which is almost certainly incorrect. So what I would like to see is a function that can tell you whether a certain address is covered by a region of a type that is normal memory, and is occupied, i.e., EFI_RESERVED_TYPE EFI_LOADER_CODE EFI_LOADER_DATA EFI_BOOT_SERVICES_CODE EFI_BOOT_SERVICES_DATA EFI_RUNTIME_SERVICES_CODE EFI_RUNTIME_SERVICES_DATA EFI_ACPI_RECLAIM_MEMORY EFI_ACPI_MEMORY_NVS The EFI_MEMORY_RUNTIME attribute is irrelevant: the firmware itself does not have to read these tables at runtime, so it doesn't matter whether the O/S maps them on its behalf. If you could please stick that in drivers/firmware/efi/efi.c, and rework the patch to use it instead? I will move the ESRT code to it as well once this is merged. > [ 0.000000] BUG: unable to handle kernel paging request at ffffffffff280001 > [ 0.000000] IP: efi_bgrt_init+0xfb/0x153 > [ 0.000000] PGD 6e00b067 > [ 0.000000] P4D 6e00b067 > [ 0.000000] PUD 6e00d067 > [ 0.000000] PMD 6e221067 > [ 0.000000] PTE 8a08e01800000163 > [ 0.000000] > [ 0.000000] Oops: 0009 [#1] SMP > [ 0.000000] Modules linked in: > [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.12.0-rc4+ #135 > [ 0.000000] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 > [ 0.000000] task: ffffffff9840f4c0 task.stack: ffffffff98400000 > [ 0.000000] RIP: 0010:efi_bgrt_init+0xfb/0x153 > [ 0.000000] RSP: 0000:ffffffff98403d50 EFLAGS: 00010082 > [ 0.000000] RAX: ffffffffff280001 RBX: 0000000000000000 RCX: 0000000000000006 > [ 0.000000] RDX: 0a08e01800001000 RSI: 8a08e01800000163 RDI: 000000000000057e > [ 0.000000] RBP: ffffffff98403d68 R08: 0000000000000041 R09: 0000000000000002 > [ 0.000000] R10: 0000000000000000 R11: ffff8c063cff8fc6 R12: ffffffff981d1fb2 > [ 0.000000] R13: ffffffff986b4fa0 R14: 0000000000000010 R15: 0000000000000000 > [ 0.000000] FS: 0000000000000000(0000) GS:ffffffff984db000(0000) knlGS:0000000000000000 > [ 0.000000] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 0.000000] CR2: ffffffffff280001 CR3: 000000006e00a000 CR4: 00000000000406b0 > [ 0.000000] Call Trace: > [ 0.000000] ? bgrt_init+0xbc/0xbc > [ 0.000000] acpi_parse_bgrt+0xe/0x12 > [ 0.000000] acpi_table_parse+0x89/0xb8 > [ 0.000000] acpi_boot_init+0x445/0x4e2 > [ 0.000000] ? acpi_parse_x2apic+0x79/0x79 > [ 0.000000] ? dmi_ignore_irq0_timer_override+0x33/0x33 > [ 0.000000] setup_arch+0xb63/0xc82 > [ 0.000000] ? early_idt_handler_array+0x120/0x120 > [ 0.000000] start_kernel+0xb7/0x443 > [ 0.000000] ? early_idt_handler_array+0x120/0x120 > [ 0.000000] x86_64_start_reservations+0x29/0x2b > [ 0.000000] x86_64_start_kernel+0x154/0x177 > [ 0.000000] secondary_startup_64+0x9f/0x9f > [ 0.000000] Code: 3f ff eb 6c 48 bf 01 00 00 00 18 e0 08 0a be 06 00 00 00 e8 ef 2b fe ff 48 85 c0 75 0e 48 c7 c7 88 09 22 98 e8 e1 31 3f ff eb 45 <66> 44 8b 20 be 06 00 00 00 48 89 c7 8b 58 02 e8 91 2c fe ff 66 > [ 0.000000] RIP: efi_bgrt_init+0xfb/0x153 RSP: ffffffff98403d50 > [ 0.000000] CR2: ffffffffff280001 > [ 0.000000] ---[ end trace 9843d3b7cbcab26a ]--- > [ 0.000000] Kernel panic - not syncing: Attempted to kill the idle task! > [ 0.000000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! > > Fixes: 7b0a911 efi/x86: Move the EFI BGRT init code to early init code > Reported-by: Maniaxx <tripleshiftone@xxxxxxxxx> > Signed-off-by: Dave Young <dyoung@xxxxxxxxxx> > --- > drivers/firmware/efi/efi-bgrt.c | 29 +++++++++++++++++++++++++++++ > 1 file changed, 29 insertions(+) > > --- linux.orig/drivers/firmware/efi/efi-bgrt.c > +++ linux/drivers/firmware/efi/efi-bgrt.c > @@ -27,6 +27,31 @@ struct bmp_header { > u32 size; > } __packed; > > +static bool efi_bgrt_addr_valid(u64 addr) > +{ > + efi_memory_desc_t *md; > + > + if (!efi_enabled(EFI_MEMMAP)) { > + pr_err("EFI_MEMMAP is not enabled.\n"); > + return true; > + } > + > + for_each_efi_memory_desc(md) { > + u64 size; > + u64 end; > + > + if (md->type != EFI_BOOT_SERVICES_DATA) > + continue; > + > + size = md->num_pages << EFI_PAGE_SHIFT; > + end = md->phys_addr + size; > + if (addr >= md->phys_addr && addr < end) > + return true; > + } > + > + return false; > +} > + > void __init efi_bgrt_init(struct acpi_table_header *table) > { > void *image; > @@ -65,6 +90,10 @@ void __init efi_bgrt_init(struct acpi_ta > goto out; > } > > + if (!efi_bgrt_addr_valid(bgrt->image_address)) { > + pr_notice("Ignoring BGRT: invalid image address\n"); > + goto out; > + } > image = early_memremap(bgrt->image_address, sizeof(bmp_header)); > if (!image) { > pr_notice("Ignoring BGRT: failed to map image header memory\n"); -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
