> > > > Thanks for this v2. > > Introducing the 'efi_switch_mm() ' helper instead of manually > > twiddling with %cr3 seems more cleaner. > > > > I have tested this patchset on a x86_64 machine with the following > > configurations: > > > > 1. Primary kernel boot with efi=old_map 2. Primary kernel boot with > > new efi map > > > > While it seems that efi=old_map passes, the new efi map boot fails for > > me on both the two x86 machine (Dell 3050MT and a SGI - UV300 machine. > > > > It seems we are hitting a NULL pointer deference in > > 'efi_call_phys_prolog' while accessing '&efi_mm'. > > > > Please see the log below for details: > > > > [ 0.020006] BUG: unable to handle kernel NULL pointer dereference > > at (null) > > [ 0.021000] IP: switch_mm_irqs_off+0x44/0x270 > > [ 0.021000] Call Trace: > > [ 0.021000] switch_mm+0x20/0x30 > > [ 0.021000] efi_switch_mm+0x49/0x60 > > [ 0.021000] efi_call_phys_prolog+0x56/0x1b3 > > [ 0.021000] efi_enter_virtual_mode+0x3a9/0x520 > > [ 0.021000] start_kernel+0x424/0x4c8 > > [ 0.021000] ? set_init_arg+0x5a/0x5a > > [ 0.021000] ? early_idt_handler_array+0x120/0x120 > > [ 0.021000] x86_64_start_reservations+0x29/0x2b > > [ 0.021000] x86_64_start_kernel+0x151/0x174 > > [ 0.021000] secondary_startup_64+0x9f/0x9f > > [ 0.021000] Code: 2d 82 51 d9 4f 65 c7 05 0f 65 da 4f 01 00 00 00 > > 48 39 f7 0f 84 14 01 00 00 65 48 89 35 f6 64 da 4f 48 8b 86 e8 02 00 > > 00 45 89 ed <f0> 4c 0f ab 28 bf 00 00 00 80 48 03 7e 50 48 8b 05 27 b0 > > b9 00 > > [ 0.021000] RIP: switch_mm_irqs_off+0x44/0x270 RSP: ffffffffb0e035d0 > > [ 0.021000] CR2: 0000000000000000 > > [ 0.021000] ---[ end trace fb94349305e1cb8b ]--- > > [ 0.021000] Kernel panic - not syncing: Fatal exception > > [ 0.021000] ---[ end Kernel panic - not syncing: Fatal exception > > > > And I forgot to mention that I tried the patchset both with the efi/next and > linus's trees and saw the same result. > > I would be happy to help in case you need further details of the test > environment > or need help in testing this crash further. > > Regards, > Bhupesh
Hi Bhupesh, Thanks for trying the patches and raising the concern. Could you also please also give a try on qemu? (if reproducible, we will be having a common platform to start debugging) I have tested this patch set on qemu and real machines (different from one's you tried) in our lab and didn’t notice this issue. Regards, Sai N�����r��y����b�X��ǧv�^�){.n�+����{�y����^n�r���z���h�����&���G���h�(�階�ݢj"���m������z�ޖ���f���h���~�m�