Kernel panic - not syncing: softlockup caused by mount(2) MS_REMOUNT operation

Issue

• A mount(2) MS_REMOUNT, during system shutdown, caused a soft lockup
• The following call trace is seen

[883039.710379] <6>BUG: soft lockup - CPU#1 stuck for 22s! [systemd-shutdow:1]
[883039.741792] <88>Modules linked in: iptable_filter ipmi_watchdog
ipmi_devintf mptctl mptbase tcp_diag inet_diag binfmt_misc 8021q garp stp
mrp llc bonding iTCO_wdt iTCO_vendor_support intel_powerclamp coretemp
intel_rapl crc32_pclmul ghash_clmulni_intel aesni_intel lrw ipmi_ssif
gf128mul glue_helper ablk_helper cryptd sb_edac pcspkr i2c _i801 lpc_ich
edac_core hpilo mfd_core hpwdt wmi ipmi_si ipmi_msghandler acpi_power_meter
shpchp ip_tables xfs libcrc32c sd_mod crc_t10dif crct10dif_generic mgag200
syscopyarea crct10dif_pclmul sysfillrect sysimgblt crct10dif_common
i2c_algo_bit crc32c_intel serio_raw drm_kms_helper ttm drm tg3 i2c_core
mdio mtd ptp hpsa pps_core dm_mir ror dm_region_hash dm_log dm_mod sg
[last unloaded: ext4]
[883040.088540] <82>
[883040.089375] <86>CPU: 1 PID: 1 Comm: systemd-shutdow Tainted: P           ------------   3.10.0-327.59.2.el7.x86_64 #1
[883040.139093] <86>Hardware name: XX XXXXXXXX XXXXX XXXX/XXXXXXXX XXXXX XXXX, BIOS XXX 00/00/0000
[883040.178686] <86>task: ffff8810290f0000 ti: ffff8810290f8000 task.ti: ffff8810290f8000
[883040.214019] <82>RIP: 0010:[<ffffffff811f5dbc>]  [<ffffffff811f5dbc>] __d_shrink+0x4c/0xa0
[883040.250314] <86>RSP: 0018:ffff8810290fbdb0  EFLAGS: 00000246
[883040.274822] <86>RAX: ffffc90002313268 RBX: ffff880dd90698c0 RCX: 0000000000000018
[883040.308925] <86>RDX: 0000000000000000 RSI: 0000000007d4df06 RDI: ffff880dd94e1ec0
[883040.342857] <86>RBP: ffff8810290fbdb0 R08: ffff880dd94e1f40 R09: 0000000000000000
[883040.376551] <86>R10: ffff880dd94e1ec0 R11: 0000000000000000 R12: 00000000050ed3b6
[883040.410654] <86>R13: ffff8810290fbda8 R14: 0000000000000000 R15: 0000000000000000
[883040.444435] <86>FS:  00007f6ae719d840(0000) GS:ffff88103f840000(0000) knlGS:0000000000000000
[883040.482811] <86>CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[883040.510145] <86>CR2: 00007fbf2987e090 CR3: 0000000feed44000 CR4: 00000000003407e0
[883040.543882] <86>DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[883040.577941] <86>DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[883040.611684] <86>Stack:
[883040.621552] <82> ffff8810290fbdc8 ffffffff811f5e29 ffff880fee144180 ffff8810290fbe20
[883040.656835] <82> ffffffff811f7957 ffff880dd94e1ec0 ffff880dd94e1ec0 ffff880dd94e1f40
[883040.691983] <82> 000000000d75831f ffff882027145000 ffff8820271450d0 ffff8810290fbe30
[883040.726985] <86>Call Trace:
[883040.738913] <82> [<ffffffff811f5e29>] __d_drop+0x19/0x40
[883040.762635] <82> [<ffffffff811f7957>] shrink_dentry_list+0x137/0x480
[883040.791203] <82> [<ffffffff811f7d2c>] shrink_dcache_sb+0x8c/0xd0
[883040.818012] <82> [<ffffffff811e2d3c>] do_remount_sb+0x4c/0x1a0
[883040.844073] <82> [<ffffffff81201549>] do_mount+0x6a9/0xa40
[883040.868441] <82> [<ffffffff811ef824>] ? getname_flags+0xc4/0x1a0
[883040.895393] <82> [<ffffffff811ff395>] ? mntput_no_expire+0xc5/0x120
[883040.923411] <82> [<ffffffff81201976>] SyS_mount+0x96/0xf0
[883040.947524] <82> [<ffffffff81647389>] system_call_fastpath+0x16/0x1b
[883040.976231] <82>Code: e8 06 03 47 20 89 c2 d3 ea 01 d0 23 05 32 a7 87
00 48 8b 15 1f a7 87 00 48 8d 04 c2 f0 0f ba 28 00 19 d2 85 d2 75 3f 40 f6
c7 01 <48> 8b 4f 08 48 8b 77 10 75 2f 48 8b 16 83 e2 01 48 09 ca 48 85