FYI, we noticed the following commit: https://github.com/0day-ci/linux Stephen-Boyd/request_firmware-on-memory-constrained-devices/20160420-090826 commit 789b02da66944487b6100d172deb9a6f67724262 ("firmware: Support requesting firmware directly into DMA memory") on test machine: vm-kbuild-2G: 2 threads qemu-system-x86_64 -enable-kvm -cpu Haswell,+smep,+smap with 2G memory caused below changes: +------------------------------------------+------------+------------+ | | 2023627913 | 789b02da66 | +------------------------------------------+------------+------------+ | boot_successes | 6 | 4 | | boot_failures | 0 | 4 | | BUG:unable_to_handle_kernel | 0 | 4 | | Oops | 0 | 4 | | RIP:_kernel_read_file | 0 | 4 | | Kernel_panic-not_syncing:Fatal_exception | 0 | 4 | | backtrace:kernel_read_file_from_fd | 0 | 4 | | backtrace:SyS_finit_module | 0 | 4 | +------------------------------------------+------------+------------+ [ 51.544227] systemd-journald[2105]: Received request to flush runtime journal from PID 1 [ 51.548800] systemd-journald[2105]: Vacuuming... [ 51.550565] systemd-journald[2105]: Vacuuming done, freed 0 bytes [ 52.391728] BUG: unable to handle kernel NULL pointer dereference at (null) [ 52.402975] IP: [] _kernel_read_file+0x1d2/0x25f [ 52.405025] PGD 0 [ 52.406320] Oops: 0000 [#1] SMP [ 52.407826] Modules linked in: [ 52.409210] CPU: 0 PID: 3405 Comm: systemd-udevd Not tainted 4.6.0-rc3-00038-g789b02d #1 [ 52.416145] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 [ 52.427085] task: ffff88007dd22ac0 ti: ffff88007d120000 task.ti: ffff88007d120000 [ 52.429913] RIP: 0010:[] [] _kernel_read_file+0x1d2/0x25f [ 52.433042] RSP: 0018:ffff88007d123e28 EFLAGS: 00010246 [ 52.440733] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000001 [ 52.442861] RDX: 0000000000005528 RSI: 0000000000000001 RDI: ffff880059cbee28 [ 52.444886] RBP: ffff88007d123e70 R08: 0000000000000000 R09: 0000000000000000 [ 52.446912] R10: ffff88007d123b68 R11: ffffffff821ff8f4 R12: 0000000000005528 [ 52.448937] R13: 0000000000005528 R14: 0000000000000000 R15: 0000000000000000 [ 52.459052] FS: 00007fb1ef6d1880(0000) GS:ffff880075e00000(0000) knlGS:0000000000000000 [ 52.466076] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 52.474030] CR2: 0000000000000000 CR3: 000000007d10a000 CR4: 00000000000406f0 [ 52.476077] Stack: [ 52.477201] 00000000811bfc31 ffff88007d123eb8 ffff88007d944ac0 ffff88007d123ec0 [ 52.480436] ffff88007d944ac0 ffff88007d944ac0 0000000000000007 0000000000020000 [ 52.491758] 0000000000000000 ffff88007d123ea8 ffffffff811f2df0 ffff88007d123ec0 [ 52.494923] Call Trace: [ 52.496131] [] kernel_read_file_from_fd+0x49/0x65 [ 52.502112] [] SyS_finit_module+0x61/0x96 [ 52.503871] [] entry_SYSCALL_64_fastpath+0x1f/0xbd [ 52.513868] Code: 85 c0 49 89 c6 78 72 74 08 49 01 c5 4d 39 ec 7f d0 4d 39 ec 41 be fb ff ff ff 75 64 45 31 f6 45 31 ff 48 8b 45 c0 4c 89 28 31 c0 <48> 8b 3b 48 85 ff 74 0c 48 8b 97 e0 03 00 00 48 85 d2 75 0f 48 [ 52.538306] RIP [] _kernel_read_file+0x1d2/0x25f [ 52.540417] RSP [ 52.541914] CR2: 0000000000000000 [ 52.543399] ---[ end trace 32ac3a2683c66c04 ]--- [ 52.545945] blk_update_request: I/O error, dev fd0, sector 0 FYI, raw QEMU command line is: qemu-system-x86_64 -enable-kvm -cpu Haswell,+smep,+smap -kernel /pkg/linux/x86_64-nfsroot/gcc-5/789b02da66944487b6100d172deb9a6f67724262/vmlinuz-4.6.0-rc3-00038-g789b02d -append 'root=/dev/ram0 user=lkp job=/lkp/scheduled/vm-kbuild-2G-12/bisect_locktorture-300s-debian-x86_64-2015-02-07.cgz-x86_64-nfsroot-789b02da66944487b6100d172deb9a6f67724262-20160420-66425-1y5ywgq-1.yaml ARCH=x86_64 kconfig=x86_64-nfsroot branch=linux-devel/devel-catchup-201604200920 commit=789b02da66944487b6100d172deb9a6f67724262 BOOT_IMAGE=/pkg/linux/x86_64-nfsroot/gcc-5/789b02da66944487b6100d172deb9a6f67724262/vmlinuz-4.6.0-rc3-00038-g789b02d max_uptime=1500 RESULT_ROOT=/result/locktorture/300s/vm-kbuild-2G/debian-x86_64-2015-02-07.cgz/x86_64-nfsroot/gcc-5/789b02da66944487b6100d172deb9a6f67724262/0 LKP_SERVER=inn earlyprintk=ttyS0,115200 systemd.log_level=err debug apic=debug sysrq_always_enabled rcupdate.rcu_cpu_stall_timeout=100 panic=-1 softlockup_panic=1 nmi_watchdog=panic oops=panic load_ramdisk=2 prompt_ramdisk=0 console=ttyS0,115200 console=tty0 vga=normal rw ip=::::vm-kbuild-2G-12::dhcp' -initrd /fs/sde1/initrd-vm-kbuild-2G-12 -m 2048 -smp 2 -device e1000,netdev=net0 -netdev user,id=net0,hostfwd=tcp::23027-:22 -boot order=nc -no-reboot -watchdog i6300esb -rtc base=localtime -drive file=/fs/sde1/disk0-vm-kbuild-2G-12,media=disk,if=virtio -drive file=/fs/sde1/disk1-vm-kbuild-2G-12,media=disk,if=virtio -drive file=/fs/sde1/disk2-vm-kbuild-2G-12,media=disk,if=virtio -drive file=/fs/sde1/disk3-vm-kbuild-2G-12,media=disk,if=virtio -drive file=/fs/sde1/disk4-vm-kbuild-2G-12,media=disk,if=virtio -drive file=/fs/sde1/disk5-vm-kbuild-2G-12,media=disk,if=virtio -drive file=/fs/sde1/disk6-vm-kbuild-2G-12,media=disk,if=virtio -pidfile /dev/shm/kboot/pid-vm-kbuild-2G-12 -serial file:/dev/shm/kboot/serial-vm-kbuild-2G-12 -daemonize -display none -monitor null To reproduce: git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git cd lkp-tests bin/lkp install job.yaml # job file is attached in this email bin/lkp run job.yaml Thanks, Kernel Test Robot