On Mon, May 08, 2017 at 12:25:23PM -0700, Sai Praneeth Prakhya wrote: > From: Sai Praneeth <sai.praneeth.prakhya@xxxxxxxxx> > > Booting kexec kernel with "efi=old_map" in kernel command line hits > kernel panic as shown below. > > [ 0.001000] BUG: unable to handle kernel paging request at ffff88007fe78070 > [ 0.001000] IP: virt_efi_set_variable.part.7+0x63/0x1b0 > [ 0.001000] PGD 7ea28067 > [ 0.001000] PUD 7ea2b067 > [ 0.001000] PMD 7ea2d067 > [ 0.001000] PTE 0 > [ 0.001000] > [ 0.001000] Oops: 0000 [#1] SMP > [ 0.001000] Modules linked in: > [ 0.001000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.11.0-rc2-yocto-standard+ #229 > [ 0.001000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 > [ 0.001000] task: ffffffff82022500 task.stack: ffffffff82000000 > [ 0.001000] RIP: 0010:virt_efi_set_variable.part.7+0x63/0x1b0 > [ 0.001000] RSP: 0000:ffffffff82003dc0 EFLAGS: 00010246 > [ 0.001000] RAX: ffff88007fe78018 RBX: ffffffff82050300 RCX: 0000000000000007 > [ 0.001000] RDX: ffffffff82003e50 RSI: ffffffff82050300 RDI: ffffffff82050300 > [ 0.001000] RBP: ffffffff82003e08 R08: 0000000000000000 R09: 0000000000000000 > [ 0.001000] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff82003e50 > [ 0.001000] R13: 0000000000000007 R14: 0000000000000246 R15: 0000000000000000 > [ 0.001000] FS: 0000000000000000(0000) GS:ffff88007fa00000(0000) knlGS:0000000000000000 > [ 0.001000] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 0.001000] CR2: ffff88007fe78070 CR3: 000000007da1d000 CR4: 00000000000006b0 > [ 0.001000] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > [ 0.001000] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > [ 0.001000] Call Trace: > [ 0.001000] virt_efi_set_variable+0x5d/0x70 > [ 0.001000] efi_delete_dummy_variable+0x7a/0x80 > [ 0.001000] efi_enter_virtual_mode+0x3f6/0x4a7 > [ 0.001000] start_kernel+0x375/0x400 > [ 0.001000] x86_64_start_reservations+0x2a/0x2c > [ 0.001000] x86_64_start_kernel+0x168/0x176 > [ 0.001000] start_cpu+0x14/0x14 > [ 0.001000] Code: 04 b0 84 ff 80 3d c5 56 b3 00 00 4c 8b 44 24 08 75 > 6b 9c 41 5e 48 8b 05 9c 78 99 00 4d 89 c1 48 89 de 4d 89 f8 44 89 e9 4c > 89 e2 <48> 8b 40 58 48 8b 78 58 e8 b0 2d 88 ff 48 c7 c6 b6 1d f4 81 4c > [ 0.001000] RIP: virt_efi_set_variable.part.7+0x63/0x1b0 RSP: ffffffff82003dc0 > [ 0.001000] CR2: ffff88007fe78070 > [ 0.001000] ---[ end trace 0000000000000000 ]--- > [ 0.001000] Kernel panic - not syncing: Attempted to kill the idle task! > [ 0.001000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! > > This happens because efi=old_map doesn't use efi_pgd but rather it uses > kernel's pgd. We don't hit the same panic in a regular kernel because > it uses old_map_region() and not __map_region(). > This issue can be reproduced on OVMF. This patch works to fix problem. Tested-by: Lee, Chun-Yi <jlee@xxxxxxxx> > Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@xxxxxxxxx> > Cc: Borislav Petkov <bp@xxxxxxxxx> > Cc: Ricardo Neri <ricardo.neri@xxxxxxxxx> > Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx> > Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> > Cc: Ravi Shankar <ravi.v.shankar@xxxxxxxxx> Thanks a lot! Joey Lee -- 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
