FYI, we noticed the following commit: https://github.com/0day-ci/linux Calvin-Owens/fs-Assert-on-module-file_operations-without-an-owner/20161008-045103 commit 148e828376ac797fe7b6a9b36301e4d109db97b7 ("fs: Assert on module file_operations without an owner") in testcase: boot on test machine: qemu-system-x86_64 -enable-kvm -cpu host -smp 2 -m 1G caused below changes: +----------------------------------------------------------------------------+------------+------------+ | | 2ab704a47e | 148e828376 | +----------------------------------------------------------------------------+------------+------------+ | boot_successes | 2 | 5 | | boot_failures | 4 | 13 | | BUG:kernel_hang_in_test_stage | 2 | | | WARNING:at_fs/sysfs/dir.c:#sysfs_warn_dup | 2 | 4 | | calltrace:parport_pc_init | 2 | 4 | | calltrace:SyS_finit_module | 2 | 4 | | WARNING:at_lib/kobject.c:#kobject_add_internal | 2 | 4 | | WARNING:at_fs/open.c:#do_dentry_open | 0 | 11 | | calltrace:SyS_open | 0 | 11 | | Kernel_panic-not_syncing:VFS:Unable_to_mount_root_fs_on_unknown-block(#,#) | 0 | 2 | | calltrace:prepare_namespace | 0 | 2 | +----------------------------------------------------------------------------+------------+------------+ [ 5.032473] [ 5.039317] -1G-17/boot-1-debian-x86_64-2016-08-31.cgz-148e828376ac797fe7b6a9b36301e4d109db97b7-20161008-50461-l76q6n-0.yaml&job_state=running -o /dev/null [ 5.323019] ------------[ cut here ]------------ [ 5.324673] WARNING: CPU: 0 PID: 407 at fs/open.c:719 do_dentry_open+0x210/0x350 [ 5.327689] No fops owner at ffffffffa01d5a00 in [nfsv4] [ 5.329424] Modules linked in: rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver sr_mod cdrom sg ata_generic pata_acpi sb_edac edac_core crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel ppdev aesni_intel ata_piix lrw gf128mul glue_helper ablk_helper cryptd snd_pcm snd_timer snd soundcore pcspkr libata serio_raw i2c_piix4 parport_pc parport floppy acpi_cpufreq ip_tables [ 5.342863] CPU: 0 PID: 407 Comm: wrapper Not tainted 4.8.0-09940-g148e828 #13 [ 5.345751] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 [ 5.348544] ffffc9000072bb38 ffffffff81454e59 ffffc9000072bb88 0000000000000000 [ 5.351410] ffffc9000072bb78 ffffffff8107ff5b 000002cf3f41c9c0 ffff88003f962800 [ 5.354180] 0000000000000000 ffff88003f962810 ffff88003f2fbcc0 ffff88003f6ae1b8 [ 5.356944] Call Trace: [ 5.357991] [] dump_stack+0x63/0x8a [ 5.359462] [] __warn+0xcb/0xf0 [ 5.360872] [] warn_slowpath_fmt+0x4f/0x60 [ 5.362443] [] do_dentry_open+0x210/0x350 [ 5.364427] [] ? nfs_force_lookup_revalidate+0x20/0x20 [ 5.366545] [] finish_open+0x2f/0x40 [ 5.368358] [] nfs_atomic_open+0x1e2/0x570 [ 5.370272] [] path_openat+0xd24/0x13e0 [ 5.372150] [] ? unmap_page_range+0x6c6/0x910 [ 5.374112] [] ? do_wp_page+0xfc/0x830 [ 5.375989] [] do_filp_open+0x7e/0xe0 [ 5.377693] [] ? getname_flags+0x4f/0x1f0 [ 5.379472] [] ? __alloc_fd+0xca/0x180 [ 5.381189] [] do_sys_open+0x123/0x200 [ 5.382926] [] SyS_open+0x1e/0x20 [ 5.384577] [] entry_SYSCALL_64_fastpath+0x1a/0xa9 [ 5.386705] ---[ end trace 6c0092634b9a9a26 ]--- [ 5.386705] ---[ end trace 6c0092634b9a9a26 ]--- Thanks, Xiaolong