Kernel panics, with the message "kernel BUG at fs/dcache.c:672!" when attempting to mount a vxfs file system

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Article ID: 100032476

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Description

Error Message

crash> sys
      KERNEL: ./vmlinux
    DUMPFILE: ./vmcore  [PARTIAL DUMP]
...
       PANIC: "kernel BUG at fs/dcache.c:672!"
crash> bt
PID: 11312  TASK: ffff8810166e7520  CPU: 12  COMMAND: "mount.vxfs"   
 #0 [ffff881018563640] machine_kexec at ffffffff8103d1ab
 #1 [ffff8810185636a0] crash_kexec at ffffffff810cc4a2
 #2 [ffff881018563770] oops_end at ffffffff8153cff0
 #3 [ffff8810185637a0] die at ffffffff81010f5b
 #4 [ffff8810185637d0] do_trap at ffffffff8153c844
 #5 [ffff881018563830] do_invalid_op at ffffffff8100cf55
 #6 [ffff8810185638d0] invalid_op at ffffffff8100c01b
    [exception RIP: shrink_dcache_for_umount_subtree+680]
    RIP: ffffffff811acef8  RSP: ffff881018563988  RFLAGS: 00010296
    RAX: 000000000000005a  RBX: ffff88200744f480  RCX: 0000000000002aec
    RDX: 0000000000000000  RSI: 0000000000000046  RDI: 0000000000000246
    RBP: ffff8810185639c8   R8: 0000000000000000   R9: ffffffff81649480
    R10: 0000000000000001  R11: 0000000000000000  R12: 0000000000000000
    R13: ffffffff81a863c0  R14: ffff882019f11c00  R15: ffff88200744f4e0
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #7 [ffff881018563980] shrink_dcache_for_umount_subtree at ffffffff811acef8
 #8 [ffff8810185639d0] shrink_dcache_for_umount at ffffffff811acf36
 #9 [ffff8810185639f0] generic_shutdown_super at ffffffff8119404f
#10 [ffff881018563a10] kill_block_super at ffffffff81194141
#11 [ffff881018563a30] vx_kill_sb at ffffffffa055e31f [vxfs]
#12 [ffff881018563a50] deactivate_super at ffffffff81194917
#13 [ffff881018563a70] mntput_no_expire at ffffffff811b48af
#14 [ffff881018563aa0] path_put at ffffffff811a0511
#15 [ffff881018563ac0] hook_mountpoint at ffffffffa0af6e32 [sisfim]  
#16 [ffff881018563de0] hook_mount at ffffffffa0afea7f [sisfim]
#17 [ffff881018563f80] system_call_fastpath at ffffffff8100b0d2

Cause

Review the panic string and backtrace from the crash dump, or vmcore. The kernel "BUG" at fs/dcache.c is triggered by hook_mount from the module sisfim. Sisfim is a component of Symantec Critical Protection.

Resolution

Stop, or disable, sisfim.
Note: Check the specific procedure from software vendor (Symantec)

After sisfim is stopped, the file system should be able to be mounted.

 

Issue/Introduction

When trying to mount a vxfs file system, the mount command hangs. The Linux kernel will panic, or "crash," with the panic string "kernel BUG at fs/dcache.c:672!"

The mount command itself stops responding, or "hangs" (Figure 1).

Figure 1# mount -t vxfs /dev/vx/dsk/<dg>/<vol> /<mnt>log replay in progressreplay complete - marking super-block as CLEAN

The command line becomes unresponsive. Eventually, the OS panics.

Note: This may also affect new file systems and mount points.