FYI, we noticed the following commit (built with gcc-6): commit: fd0002870b453c58d0d8c195954f5049bc6675fb ("vfs: Implement a filesystem superblock creation/configuration context") https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master in testcase: boot on test machine: qemu-system-x86_64 -enable-kvm -cpu Haswell,+smep,+smap -smp 2 -m 1G caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): +------------------------------------------+------------+------------+ | | bae551929c | fd0002870b | +------------------------------------------+------------+------------+ | boot_successes | 6 | 2 | | boot_failures | 0 | 11 | | BUG:KASAN:null-ptr-deref_in_n | 0 | 11 | | BUG:unable_to_handle_kernel | 0 | 11 | | Oops:#[##] | 0 | 11 | | RIP:nfs_fs_mount | 0 | 11 | | Kernel_panic-not_syncing:Fatal_exception | 0 | 11 | +------------------------------------------+------------+------------+ [ 18.557980] BUG: KASAN: null-ptr-deref in nfs_fs_mount+0x901/0x1220 [ 18.559674] Read of size 1 at addr 0000000000000000 by task mount.nfs/357 [ 18.561456] [ 18.562063] CPU: 0 PID: 357 Comm: mount.nfs Not tainted 4.19.0-rc1-00104-gfd00028 #1 [ 18.564199] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 18.566478] Call Trace: [ 18.567308] kasan_report+0x107/0x330 [ 18.568403] nfs_fs_mount+0x901/0x1220 [ 18.569523] ? kmem_cache_free+0x70/0x170 [ 18.570710] ? nfs_compare_super+0x440/0x440 [ 18.571944] ? nd_jump_link+0xb0/0xb0 [ 18.573039] ? ksys_mount+0x5a/0xc0 [ 18.574106] ? strcmp+0x30/0x50 [ 18.575083] ? nfs_clone_super+0x150/0x150 [ 18.576273] ? nfs_remount+0x890/0x890 [ 18.577395] ? vfs_parse_fs_string+0xad/0xe0 [ 18.578629] ? nfs_compare_super+0x440/0x440 [ 18.579895] ? legacy_get_tree+0x83/0x180 [ 18.581069] legacy_get_tree+0x83/0x180 [ 18.582204] vfs_get_tree+0xaf/0x250 [ 18.583272] do_mount+0x39b/0xfe0 [ 18.584282] ? __might_sleep+0x2e/0xd0 [ 18.585394] ? __might_sleep+0x2e/0xd0 [ 18.586507] ? copy_mount_string+0x20/0x20 [ 18.587697] ? copy_mount_options+0x3a/0x1c0 [ 18.588842] ? copy_mount_options+0xf1/0x1c0 [ 18.589936] ksys_mount+0x79/0xc0 [ 18.590831] __x64_sys_mount+0x5d/0x70 [ 18.591819] do_syscall_64+0xac/0x3d0 [ 18.593009] ? syscall_return_slowpath+0xb0/0xb0 [ 18.594185] ? mm_fault_error+0x1c0/0x1c0 [ 18.595256] ? __put_user_4+0x1b/0x30 [ 18.596222] ? async_page_fault+0x8/0x30 [ 18.597251] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 18.598505] RIP: 0033:0x7fd79e7f424a [ 18.599463] Code: 48 8b 0d 51 fc 2a 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 1e fc 2a 00 f7 d8 64 89 01 48 [ 18.606261] RSP: 002b:00007ffe34069b58 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5 [ 18.608156] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd79e7f424a [ 18.609829] RDX: 0000558512e8cf70 RSI: 0000558512e8cf50 RDI: 0000558512e8b210 [ 18.611506] RBP: 00007ffe34069d50 R08: 0000558512e98320 R09: 0000000000000060 [ 18.613359] R10: 0000000000000000 R11: 0000000000000202 R12: 00007fd79f138410 [ 18.615038] R13: 00007ffe34069d50 R14: 00007ffe34069c50 R15: 0000558512e98300 [ 18.616716] ================================================================== [ 18.618528] Disabling lock debugging due to kernel taint [ 18.762009] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 [ 18.764184] PGD 0 P4D 0 [ 18.765016] Oops: 0000 [#1] PREEMPT KASAN PTI [ 18.766279] CPU: 0 PID: 357 Comm: mount.nfs Tainted: G B 4.19.0-rc1-00104-gfd00028 #1 [ 18.768705] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 18.770938] RIP: 0010:nfs_fs_mount+0x901/0x1220 [ 18.772208] Code: 02 74 06 66 83 f8 0a 75 19 48 8d bb 2a 01 00 00 66 41 c1 c4 08 e8 df 33 f1 ff 66 44 89 a3 2a 01 00 00 4c 89 ef e8 bf 32 f1 ff <41> 80 7d 00 5b 0f 84 4a 08 00 00 be 3a 00 00 00 4c 89 ef e8 b7 9a [ 18.776851] RSP: 0000:ffff88001ff1fb70 EFLAGS: 00010292 [ 18.778318] RAX: ffff88001ed45c00 RBX: ffff880017e19b80 RCX: 0000000000000000 [ 18.780200] RDX: 0000000000000001 RSI: dffffc0000000000 RDI: ffffffff82cdcf80 [ 18.782055] RBP: ffff88001ff1fc90 R08: fffffbfff0495731 R09: fffffbfff0495730 [ 18.783938] R10: 0000000000000003 R11: fffffbfff0495731 R12: 0000000000000000 [ 18.785811] R13: 0000000000000000 R14: 0000000000001000 R15: ffff880017e19ca8 [ 18.787709] FS: 00007fd79f138480(0000) GS:ffffffff82465000(0000) knlGS:0000000000000000 [ 18.789910] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 18.791455] CR2: 0000000000000000 CR3: 000000003fb6a003 CR4: 00000000000606f0 [ 18.793339] Call Trace: [ 18.794147] ? kmem_cache_free+0x70/0x170 [ 18.795296] ? nfs_compare_super+0x440/0x440 [ 18.796504] ? nd_jump_link+0xb0/0xb0 [ 18.797603] ? ksys_mount+0x5a/0xc0 [ 18.798643] ? strcmp+0x30/0x50 [ 18.799610] ? nfs_clone_super+0x150/0x150 [ 18.800813] ? nfs_remount+0x890/0x890 [ 18.801945] ? vfs_parse_fs_string+0xad/0xe0 [ 18.803155] ? nfs_compare_super+0x440/0x440 [ 18.804383] ? legacy_get_tree+0x83/0x180 [ 18.805558] legacy_get_tree+0x83/0x180 [ 18.806690] vfs_get_tree+0xaf/0x250 [ 18.807765] do_mount+0x39b/0xfe0 [ 18.808776] ? __might_sleep+0x2e/0xd0 [ 18.809792] ? __might_sleep+0x2e/0xd0 [ 18.810887] ? copy_mount_string+0x20/0x20 [ 18.812072] ? copy_mount_options+0x3a/0x1c0 [ 18.813310] ? copy_mount_options+0xf1/0x1c0 [ 18.814555] ksys_mount+0x79/0xc0 [ 18.815572] __x64_sys_mount+0x5d/0x70 [ 18.816683] do_syscall_64+0xac/0x3d0 [ 18.817785] ? syscall_return_slowpath+0xb0/0xb0 [ 18.819175] ? mm_fault_error+0x1c0/0x1c0 [ 18.820350] ? __put_user_4+0x1b/0x30 [ 18.821455] ? async_page_fault+0x8/0x30 [ 18.822622] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 18.824024] RIP: 0033:0x7fd79e7f424a [ 18.825087] Code: 48 8b 0d 51 fc 2a 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 1e fc 2a 00 f7 d8 64 89 01 48 [ 18.829774] RSP: 002b:00007ffe34069b58 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5 [ 18.831873] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd79e7f424a [ 18.833764] RDX: 0000558512e8cf70 RSI: 0000558512e8cf50 RDI: 0000558512e8b210 [ 18.835657] RBP: 00007ffe34069d50 R08: 0000558512e98320 R09: 0000000000000060 [ 18.837543] R10: 0000000000000000 R11: 0000000000000202 R12: 00007fd79f138410 [ 18.839426] R13: 00007ffe34069d50 R14: 00007ffe34069c50 R15: 0000558512e98300 [ 18.841309] Modules linked in: crc32_pclmul ghash_clmulni_intel aesni_intel crypto_simd input_leds led_class floppy cmdlinepart [ 18.844315] CR2: 0000000000000000 [ 19.028656] ---[ end trace df17e7a878a94ae1 ]--- To reproduce: git clone https://github.com/intel/lkp-tests.git cd lkp-tests bin/lkp qemu -k job-script # job-script is attached in this email Thanks, lkp