Maniaxx <tripleshiftone@xxxxxxxxx> reported a kernel boot failure of below: (emulated the panic by using same invalid phys addr in code) There are also a bug in bugzilla.kernel.org: https://bugzilla.kernel.org/show_bug.cgi?id=195633 The reported panic 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. In a kernel before above commit bgrt initializes late and use ioremap to map the image address. Ioremap validate 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. [ 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> --- v1->v2: Ard: move EFI_MEMMAP checking out and improve the patchlog. drivers/firmware/efi/efi-bgrt.c | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-) --- linux-x86.orig/drivers/firmware/efi/efi-bgrt.c +++ linux-x86/drivers/firmware/efi/efi-bgrt.c @@ -27,6 +27,26 @@ struct bmp_header { u32 size; } __packed; +static bool efi_bgrt_addr_valid(u64 addr) +{ + efi_memory_desc_t *md; + + 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; @@ -36,7 +56,7 @@ void __init efi_bgrt_init(struct acpi_ta if (acpi_disabled) return; - if (!efi_enabled(EFI_BOOT)) + if (!efi_enabled(EFI_MEMMAP)) return; if (table->length < sizeof(bgrt_tab)) { @@ -65,6 +85,10 @@ 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
