FYI, we noticed the following commit: commit: baeb74f5f530bcf19fdc165d9552ee9303414880 ("fs: fix kernel_read prototype") git://git.infradead.org/users/hch/misc.git kernel-readwrite in testcase: boot on test machine: qemu-system-x86_64 -enable-kvm -m 420M caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): +------------------------------------------+------------+------------+ | | a29473601a | baeb74f5f5 | +------------------------------------------+------------+------------+ | boot_successes | 8 | 0 | | boot_failures | 0 | 6 | | BUG:unable_to_handle_kernel | 0 | 6 | | Oops:#[##] | 0 | 6 | | Kernel_panic-not_syncing:Fatal_exception | 0 | 6 | +------------------------------------------+------------+------------+ [ 3.015392] BUG: unable to handle kernel NULL pointer dereference at (null) [ 3.016009] IP: rw_verify_area+0x17/0xb5 [ 3.016009] PGD 0 [ 3.016009] P4D 0 [ 3.016009] [ 3.016009] Oops: 0000 [#1] SMP [ 3.016009] Modules linked in: [ 3.016009] CPU: 0 PID: 126 Comm: kworker/u2:0 Not tainted 4.13.0-rc7-00012-gbaeb74f #41 [ 3.016009] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-20161025_171302-gandalf 04/01/2014 [ 3.016009] task: ffff8a067376c380 task.stack: ffffa24f80a54000 [ 3.016009] RIP: 0010:rw_verify_area+0x17/0xb5 [ 3.016009] RSP: 0018:ffffa24f80a57e10 EFLAGS: 00010202 [ 3.016009] RAX: 00000000ffffffea RBX: 0000000000000080 RCX: 0000000000000080 [ 3.016009] RDX: 0000000000000000 RSI: ffff8a0672371480 RDI: 0000000000000000 [ 3.016009] RBP: ffffa24f80a57e48 R08: 000000000002801d R09: ffff8a0675cfc048 [ 3.016009] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8a0672371480 [ 3.016009] R13: ffff8a0674046b00 R14: 0000000000000000 R15: ffff8a067376c380 [ 3.016009] FS: 0000000000000000(0000) GS:ffff8a0679e00000(0000) knlGS:0000000000000000 [ 3.016009] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 3.016009] CR2: 0000000000000000 CR3: 000000003002c000 CR4: 00000000000006f0 [ 3.016009] Call Trace: [ 3.016009] ? vfs_read+0x92/0xef [ 3.016009] kernel_read+0x2c/0x38 [ 3.016009] prepare_binprm+0x138/0x143 [ 3.016009] do_execveat_common+0x3c2/0x70f [ 3.016009] do_execve+0x23/0x25 [ 3.016009] call_usermodehelper_exec_async+0x100/0x12d [ 3.016009] ? __request_module+0x42e/0x42e [ 3.016009] ret_from_fork+0x2a/0x40 [ 3.016009] Code: 48 63 c3 48 83 c4 18 5b 41 5a 41 5c 41 5d 41 5e 41 5f 5d c3 0f 1f 44 00 00 48 85 c9 4c 8b 4e 20 b8 ea ff ff ff 0f 88 9d 00 00 00 <48> 8b 12 48 85 d2 79 1e f6 86 8d 00 00 00 20 0f 84 88 00 00 00 [ 3.016009] RIP: rw_verify_area+0x17/0xb5 RSP: ffffa24f80a57e10 [ 3.016009] CR2: 0000000000000000 [ 3.016009] ---[ end trace 892b6c32748834c4 ]--- To reproduce: git clone https://github.com/01org/lkp-tests.git cd lkp-tests bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email Thanks, Xiaolong