FYI, we noticed the following commit: commit: f2a6a7050109e0a5c7a84c70aa6010f682b2f1ee ("x86: Convert the rest of the code to support p4d_t") https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master in testcase: boot on test machine: qemu-system-x86_64 -enable-kvm -smp 2 -m 512M caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): +-------------------------------------------------------------------------------------------------+------------+------------+ | | 907cd43902 | f2a6a70501 | +-------------------------------------------------------------------------------------------------+------------+------------+ | boot_successes | 0 | 0 | | boot_failures | 8 | 6 | | invoked_oom-killer:gfp_mask=0x | 2 | 2 | | Mem-Info | 8 | 6 | | Kernel_panic-not_syncing:Out_of_memory_and_no_killable_processes | 2 | 2 | | page_allocation_failure:order:#,mode:#(__GFP_COMP|__GFP_NOTRACK),nodemask=(null) | 6 | 4 | | page_allocation_failure:order:#,mode:#(__GFP_COMP|__GFP_HARDWALL|__GFP_NOTRACK),nodemask=(null) | 6 | | | Kernel_panic-not_syncing:can't_set_nsfs_up | 6 | | | BUG:KASAN:null-ptr-deref_on_address | 0 | 4 | | BUG:unable_to_handle_kernel | 0 | 4 | | Oops:#[##] | 0 | 4 | | Kernel_panic-not_syncing:Fatal_exception | 0 | 4 | +-------------------------------------------------------------------------------------------------+------------+------------+ [ 0.225718] BUG: KASAN: null-ptr-deref on address 0000000000000020 [ 0.225718] BUG: KASAN: null-ptr-deref on address 0000000000000020 [ 0.226666] Write of size 8 by task swapper/0/0 [ 0.226666] Write of size 8 by task swapper/0/0 [ 0.226666] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.11.0-rc2-00278-gf2a6a70 #2 [ 0.226666] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.11.0-rc2-00278-gf2a6a70 #2 [ 0.226666] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-20161025_171302-gandalf 04/01/2014 [ 0.226666] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-20161025_171302-gandalf 04/01/2014 [ 0.226666] Call Trace: [ 0.226666] Call Trace: [ 0.226666] dump_stack+0x149/0x1eb [ 0.226666] dump_stack+0x149/0x1eb [ 0.226666] kasan_report+0x61d/0x670 [ 0.226666] kasan_report+0x61d/0x670 [ 0.226666] ? proc_sys_init+0x30/0x87 [ 0.226666] ? proc_sys_init+0x30/0x87 [ 0.226666] ? __asan_loadN+0xf/0x20 [ 0.226666] ? __asan_loadN+0xf/0x20 [ 0.226666] ? proc_mkdir_data+0xb6/0x170 [ 0.226666] ? proc_mkdir_data+0xb6/0x170 [ 0.226666] __asan_store8+0x61/0x70 [ 0.226666] __asan_store8+0x61/0x70 [ 0.226666] proc_sys_init+0x30/0x87 [ 0.226666] proc_sys_init+0x30/0x87 [ 0.226666] proc_root_init+0xf4/0x11e [ 0.226666] proc_root_init+0xf4/0x11e [ 0.226666] start_kernel+0x8b5/0x990 [ 0.226666] start_kernel+0x8b5/0x990 [ 0.226666] ? thread_stack_cache_init+0x35/0x35 [ 0.226666] ? thread_stack_cache_init+0x35/0x35 [ 0.226666] ? __asan_loadN+0xf/0x20 [ 0.226666] ? __asan_loadN+0xf/0x20 [ 0.226666] ? early_idt_handler_array+0x120/0x120 [ 0.226666] ? early_idt_handler_array+0x120/0x120 [ 0.226666] x86_64_start_reservations+0x6b/0x8c [ 0.226666] x86_64_start_reservations+0x6b/0x8c [ 0.226666] x86_64_start_kernel+0x199/0x1bd [ 0.226666] x86_64_start_kernel+0x199/0x1bd [ 0.226666] start_cpu+0x14/0x14 [ 0.226666] start_cpu+0x14/0x14 [ 0.226666] ================================================================== [ 0.226666] ================================================================== [ 0.226666] Disabling lock debugging due to kernel taint [ 0.226666] Disabling lock debugging due to kernel taint [ 0.226704] BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 [ 0.226704] BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 [ 0.228866] IP: proc_sys_init+0x35/0x87 [ 0.228866] IP: proc_sys_init+0x35/0x87 [ 0.229726] PGD 0 [ 0.229726] PGD 0 [ 0.229732] P4D 0 [ 0.229732] P4D 0 [ 0.229999] [ 0.229999] [ 0.229999] Oops: 0002 [#1] SMP KASAN [ 0.229999] Oops: 0002 [#1] SMP KASAN [ 0.229999] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G B 4.11.0-rc2-00278-gf2a6a70 #2 [ 0.229999] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G B 4.11.0-rc2-00278-gf2a6a70 #2 [ 0.229999] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-20161025_171302-gandalf 04/01/2014 [ 0.229999] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-20161025_171302-gandalf 04/01/2014 [ 0.229999] task: ffffffff8762a380 task.stack: ffffffff87600000 [ 0.229999] task: ffffffff8762a380 task.stack: ffffffff87600000 [ 0.229999] RIP: 0010:proc_sys_init+0x35/0x87 [ 0.229999] RIP: 0010:proc_sys_init+0x35/0x87 [ 0.229999] RSP: 0000:ffffffff87607e00 EFLAGS: 00010286 [ 0.229999] RSP: 0000:ffffffff87607e00 EFLAGS: 00010286 [ 0.229999] RAX: ffffffff8762a380 RBX: 332459ea0398d339 RCX: ffffffff8128f6d6 [ 0.229999] RAX: ffffffff8762a380 RBX: 332459ea0398d339 RCX: ffffffff8128f6d6 [ 0.229999] RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000028 [ 0.229999] RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000028 [ 0.229999] RBP: ffffffff87607e10 R08: fffffbfff11abe65 R09: fffffbfff11abe64 [ 0.229999] RBP: ffffffff87607e10 R08: fffffbfff11abe65 R09: fffffbfff11abe64 [ 0.229999] R10: ffffffff88d5f327 R11: fffffbfff11abe65 R12: 0000000000000000 [ 0.229999] R10: ffffffff88d5f327 R11: fffffbfff11abe65 R12: 0000000000000000 [ 0.229999] R13: 0000000000000000 R14: 0000000000000002 R15: 0000000000000002 [ 0.229999] R13: 0000000000000000 R14: 0000000000000002 R15: 0000000000000002 [ 0.229999] FS: 0000000000000000(0000) GS:ffff880000200000(0000) knlGS:0000000000000000 [ 0.229999] FS: 0000000000000000(0000) GS:ffff880000200000(0000) knlGS:0000000000000000 [ 0.229999] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 0.229999] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 0.229999] CR2: 0000000000000020 CR3: 000000000761e000 CR4: 00000000000006b0 [ 0.229999] CR2: 0000000000000020 CR3: 000000000761e000 CR4: 00000000000006b0 [ 0.229999] Call Trace: [ 0.229999] Call Trace: [ 0.229999] proc_root_init+0xf4/0x11e [ 0.229999] proc_root_init+0xf4/0x11e [ 0.229999] start_kernel+0x8b5/0x990 [ 0.229999] start_kernel+0x8b5/0x990 [ 0.229999] ? thread_stack_cache_init+0x35/0x35 [ 0.229999] ? thread_stack_cache_init+0x35/0x35 [ 0.229999] ? __asan_loadN+0xf/0x20 [ 0.229999] ? __asan_loadN+0xf/0x20 [ 0.229999] ? early_idt_handler_array+0x120/0x120 [ 0.229999] ? early_idt_handler_array+0x120/0x120 [ 0.229999] x86_64_start_reservations+0x6b/0x8c [ 0.229999] x86_64_start_reservations+0x6b/0x8c [ 0.229999] x86_64_start_kernel+0x199/0x1bd [ 0.229999] x86_64_start_kernel+0x199/0x1bd [ 0.229999] start_cpu+0x14/0x14 [ 0.229999] start_cpu+0x14/0x14 [ 0.229999] Code: 1d 51 9f fd e8 08 7a 5b f7 31 f6 48 c7 c7 80 af a0 85 e8 fa fa 96 f7 48 8d 78 20 49 89 c4 48 31 eb e8 3b db 7b f7 49 8d 7c 24 28 <49> c7 44 24 20 40 c0 a0 85 e8 28 db 7b f7 49 8d 7c 24 08 49 c7 [ 0.229999] Code: 1d 51 9f fd e8 08 7a 5b f7 31 f6 48 c7 c7 80 af a0 85 e8 fa fa 96 f7 48 8d 78 20 49 89 c4 48 31 eb e8 3b db 7b f7 49 8d 7c 24 28 <49> c7 44 24 20 40 c0 a0 85 e8 28 db 7b f7 49 8d 7c 24 08 49 c7 [ 0.229999] RIP: proc_sys_init+0x35/0x87 RSP: ffffffff87607e00 [ 0.229999] RIP: proc_sys_init+0x35/0x87 RSP: ffffffff87607e00 [ 0.229999] CR2: 0000000000000020 [ 0.229999] CR2: 0000000000000020 [ 0.229999] ---[ end trace d7042a2b0fc5a1e6 ]--- To reproduce: git clone https://github.com/01org/lkp-tests.git cd lkp-tests bin/lkp qemu -k job-script # job-script is attached in this email Thanks, Xiaolong