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Oracle Linux: Error "kernel BUG at fs/dcache.c:928! in shrink_dcache_for_umount_subtree" (Doc ID 2541903.1)

Last updated on JUNE 24, 2020

Applies to:

Linux OS - Version Oracle Linux 5.2 to Oracle Linux 6.9 with Unbreakable Enterprise Kernel [2.6.39] [Release OL5U2 to OL6U9]
Information in this document applies to any platform.


A kernel panic occurs showing shrink_dcache_for_umount_subtree() on the console and in the /var/log/messages file:

BUG: Dentry ffff880f1510f440{i=4b687f,} still in use (1) [unmount of cifs cifs]
------------[ cut here ]------------
kernel BUG at fs/dcache.c:928!
invalid opcode: 0000 [#1] SMP
CPU 10
Modules linked in: des_generic ecb md4 nls_utf8 cifs oracleacfs(P)(U) oracleadvm(P)(U) oracleoks(P)(U) mptctl mptbase nfsd nfs_acl auth_rpcgss ipv6 lockd sunrpc acpi_cpufreq freq_table mperf bonding dm_round_robin video sbs sbshc acpi_pad acpi_memhotplug acpi_ipmi parport_pc lp parport ipmi_si ipmi_devintf ipmi_msghandler sg snd_seq_dummy cdc_ether usbnet mii ses enclosure snd_seq_oss snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss snd_pcm snd_timer snd i2c_i801 soundcore i2c_core snd_page_alloc iTCO_wdt pcspkr iTCO_vendor_support ghes hed ixgbe hwmon dca dm_multipath dm_snapshot dm_zero dm_mirror dm_region_hash dm_log dm_mod usb_storage ahci libahci sr_mod cdrom iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi shpchp mpt2sas(U) scsi_transport_sas raid_class raid1 ext3 jbd mbcache sd_mod crc_t10dif [last unloaded: microcode]

Pid: 53488, comm: umount.cifs Tainted: P 2.6.39-400.245.1.el5uek #1 Oracle Corporation SUN SERVER X4-2 /ASSY,MB,X4-2, 1U
RIP: 0010:[<ffffffff81182729>] [<ffffffff81182729>] shrink_dcache_for_umount_subtree+0x219/0x230
RSP: 0018:ffff880211c87e18 EFLAGS: 00010296
RAX: 0000000000000068 RBX: ffff8806d3815a1c RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000082 RDI: 0000000000000246
RBP: ffff880211c87e48 R08: 000000000002339d R09: ffffffff819ad740
R10: 0000000000000000 R11: 0000000000000001 R12: ffff880bfed4fc1c
R13: ffff880bfed4fbd0 R14: ffff880f1510f440 R15: ffff880f1510f4e0
FS: 00007fd8f7cdc6e0(0000) GS:ffff88407fd40000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00007f68f3437000 CR3: 0000000788b77000 CR4: 00000000001406a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process umount.cifs (pid: 53488, threadinfo ffff880211c86000, task ffff880cf5046340)
ffff883f039afe58 ffff881568c50d9c ffff881568c50d40 ffff883f039afc00
ffffffffa09170e0 0000000000000000 ffff880211c87e78 ffffffff81182797
ffff880211c87e98 0000000000000015 ffff883f039afc00 0000000000000000
Call Trace:
[<ffffffff81182797>] shrink_dcache_for_umount+0x57/0x90
[<ffffffff8116e983>] generic_shutdown_super+0x33/0x120
[<ffffffff8116eb06>] kill_anon_super+0x16/0x30
[<ffffffffa08ec14a>] cifs_kill_sb+0x1a/0x30 [cifs]
[<ffffffff8116f22d>] deactivate_locked_super+0x3d/0x80
[<ffffffff8116fcf1>] deactivate_super+0x51/0x60
[<ffffffff8118a789>] mntput_no_expire+0x99/0xe0
[<ffffffff8118aea9>] sys_umount+0x79/0xd0
[<ffffffff81511002>] system_call_fastpath+0x16/0x1b
Code: 8b 46 30 48 85 c0 74 07 48 8b 90 b0 00 00 00 48 8d 86 58 02 00 00 48 c7 c7 f0 3a 6f 81 4c 89 f6 48 89 04 24 31 c0 e8 c7 df ee ff <0f> 0b eb fe 0f 0b eb fe 0f 1f 80 00 00 00 00 0f 1f 84 00 00 00
RIP [<ffffffff81182729>] shrink_dcache_for_umount_subtree+0x219/0x230
RSP <ffff880211c87e18>



 Try to unmount a CIFS filesystem.


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