On 06/08/17 at 03:51pm, Ard Biesheuvel wrote: > 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. > > > > [ 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> > > Hi Dave, > > I'm with the program now :-) > > Could you please check your commit log for grammar? And add that the > spec you refer to is the ACPI spec? Will do both. My fault, should say it clearly when I wrote the log.. > > > --- > > 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; > > + } > > + > > Given that you already added a check for EFI_BOOT in efi_bgrt_init() > in commit 5d36982a80248 ("efi/bgrt: Skip efi_bgrt_init in case of > non-efi boot"), could we drop this check, and replace the EFI_BOOT > check you added with EFI_MEMMAP? Ok, will do. > > > + 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"); Thanks Dave -- 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
