FYI, we noticed the below changes on git://internal_merge_and_test_tree revert-18c5809b7e1183fc5ca4d104b99d53dc77723ef9-18c5809b7e1183fc5ca4d104b99d53dc77723ef9 commit 18c5809b7e1183fc5ca4d104b99d53dc77723ef9 ("fs: clear file privilege bits when mmap writing") +------------------------------------------------------------------+----------+------------+ | | v4.4-rc3 | 18c5809b7e | +------------------------------------------------------------------+----------+------------+ | boot_successes | 0 | 0 | | boot_failures | 39 | 6 | | BUG:kernel_test_oversize | 4 | | | BUG:kernel_boot_hang | 34 | 1 | | invoked_oom-killer:gfp_mask=0x | 1 | 1 | | Mem-Info | 1 | 1 | | Kernel_panic-not_syncing:Out_of_memory_and_no_killable_processes | 1 | 1 | | backtrace:power_supply_changed_work | 1 | | | INFO:possible_circular_locking_dependency_detected | 0 | 4 | | backtrace:iterate_dir | 0 | 4 | | backtrace:SyS_getdents | 0 | 4 | | backtrace:vm_mmap_pgoff | 0 | 4 | | backtrace:SyS_mmap_pgoff | 0 | 4 | | backtrace:SyS_mmap | 0 | 4 | | backtrace:kmem_cache_alloc | 0 | 1 | | backtrace:device_private_init | 0 | 1 | | backtrace:serio_handle_event | 0 | 1 | +------------------------------------------------------------------+----------+------------+ [ 54.241020] systemd-sysv-generator[171]: Ignoring K01watchdog symlink in rc6.d, not generating watchdog.service. [ 54.918926] [ 54.919580] ====================================================== [ 54.921207] [ INFO: possible circular locking dependency detected ] [ 54.922873] 4.4.0-rc3-00001-g18c5809b7 #1 Not tainted [ 54.925715] ------------------------------------------------------- [ 54.929512] systemd-journal/185 is trying to acquire lock: [ 54.929544] (&sb->s_type->i_mutex_key#7){+.+.+.}, at: [] do_mmap+0x3b6/0x670 [ 54.929545] [ 54.929545] but task is already holding lock: [ 54.929551] (&mm->mmap_sem){++++++}, at: [] vm_mmap_pgoff+0x4c/0xd0 [ 54.929552] [ 54.929552] which lock already depends on the new lock. [ 54.929552] [ 54.929553] [ 54.929553] the existing dependency chain (in reverse order) is: [ 54.929556] [ 54.929556] -> #1 (&mm->mmap_sem){++++++}: [ 54.929566] [] lock_acquire+0xa1/0xd0 [ 54.929570] [] __might_fault+0x9d/0xe0 [ 54.929586] [] filldir+0xdc/0x1b0 [ 54.929594] [] dcache_readdir+0x249/0x370 [ 54.929597] [] iterate_dir+0xb5/0x1a0 [ 54.929600] [] SyS_getdents+0xb6/0x180 [ 54.929617] [] entry_SYSCALL_64_fastpath+0x16/0x7a [ 54.929622] [ 54.929622] -> #0 (&sb->s_type->i_mutex_key#7){+.+.+.}: [ 54.929625] [] __lock_acquire+0x1e71/0x2150 [ 54.929628] [] lock_acquire+0xa1/0xd0 [ 54.929637] [] mutex_lock_nested+0x99/0x620 [ 54.929641] [] do_mmap+0x3b6/0x670 [ 54.929644] [] vm_mmap_pgoff+0x7d/0xd0 [ 54.929647] [] SyS_mmap_pgoff+0x214/0x2e0 [ 54.929662] [] SyS_mmap+0x26/0x40 [ 54.929666] [] entry_SYSCALL_64_fastpath+0x16/0x7a [ 54.929667] [ 54.929667] other info that might help us debug this: [ 54.929667] [ 54.929668] Possible unsafe locking scenario: [ 54.929668] [ 54.929668] CPU0 CPU1 [ 54.929669] ---- ---- [ 54.929671] lock(&mm->mmap_sem); [ 54.929673] lock(&sb->s_type->i_mutex_key#7); [ 54.929675] lock(&mm->mmap_sem); [ 54.929677] lock(&sb->s_type->i_mutex_key#7); [ 54.929678] [ 54.929678] *** DEADLOCK *** [ 54.929678] [ 54.929679] 1 lock held by systemd-journal/185: [ 54.929685] #0: (&mm->mmap_sem){++++++}, at: [] vm_mmap_pgoff+0x4c/0xd0 [ 54.929686] [ 54.929686] stack backtrace: [ 54.929700] CPU: 0 PID: 185 Comm: systemd-journal Not tainted 4.4.0-rc3-00001-g18c5809b7 #1 [ 54.929701] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 [ 54.929714] ffffffff8357a530 ffff88001426fc70 ffffffff816bd2d8 ffffffff8357a530 [ 54.929717] ffff88001426fcb0 ffffffff8114e758 ffff88001426fd00 ffff880000b74bc0 [ 54.929790] ffff880000b74b88 0000000000000001 0000000000000001 ffff880000b74040 [ 54.929793] Call Trace: [ 54.929814] [] dump_stack+0x7c/0xb4 [ 54.929817] [] print_circular_bug+0x2c8/0x370 [ 54.929820] [] __lock_acquire+0x1e71/0x2150 [ 54.929831] [] ? local_clock+0x4c/0x60 [ 54.929834] [] lock_acquire+0xa1/0xd0 [ 54.929837] [] ? do_mmap+0x3b6/0x670 [ 54.929841] [] mutex_lock_nested+0x99/0x620 [ 54.929843] [] ? do_mmap+0x3b6/0x670 [ 54.929846] [] ? do_mmap+0x3b6/0x670 [ 54.929849] [] do_mmap+0x3b6/0x670 [ 54.929851] [] vm_mmap_pgoff+0x7d/0xd0 [ 54.929854] [] SyS_mmap_pgoff+0x214/0x2e0 [ 54.929857] [] SyS_mmap+0x26/0x40 [ 54.929860] [] entry_SYSCALL_64_fastpath+0x16/0x7a 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, Ying Huang