Kernel crashes at configfs_readdir()+0xf4 in Red Hat Enterprise Linux 6

Solution Verified - Updated -

Issue

  • Kernel crashes with following messages when trying to capture debug data from the mount /sys/kernel/debug:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000040
IP: [<ffffffffa0274444>] configfs_readdir+0xf4/0x230 [configfs]
PGD 35595e067 PUD b7bf60067 PMD 0 
Oops: 0000 [#1] SMP 
last sysfs file: /sys/module/ipv6/initstate
CPU 9 
Modules linked in: nfs fscache nfsd lockd nfs_acl auth_rpcgss exportfs dlm configfs mptctl mptbase sunrpc pcc_cpufreq bonding 8021q garp stp llc ipv6 dm_round_robin dm_multipath video output hpilo hpwdt microcode serio_raw iTCO_wdt iTCO_vendor_support power_meter sg be2net ioatdma dca shpchp ext4 mbcache jbd2 sd_mod crc_t10dif lpfc scsi_transport_fc scsi_tgt hpsa dm_mirror dm_region_hash dm_log dm_mod [last unloaded: scsi_wait_scan]

Pid: 59185, comm: bpbkar Tainted: G        W  ---------------    2.6.32-279.1.1.el6.x86_64 #1
RIP: 0010:[<ffffffffa0274444>]  [<ffffffffa0274444>] configfs_readdir+0xf4/0x230 [configfs]
RSP: 0018:ffff8825a19d9e78  EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff883ff08d6ae0 RCX: ffff883ff08d6ad8
RDX: 0000000000000006 RSI: ffff883ff08d6a40 RDI: ffffffffa0349950
RBP: ffff8825a19d9ed8 R08: ffff883ff08d6ae0 R09: 0000000000000004
R10: 00000000000000a8 R11: 0000000000000246 R12: ffff883ff1b34800
R13: ffffffffa0349950 R14: ffff883ff08d6710 R15: ffff883ff08d6718
FS:  00007f6f6b40e720(0000) GS:ffff8820b0c20000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000040 CR3: 000000049744f000 CR4: 00000000000406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process bpbkar (pid: 59185, threadinfo ffff8825a19d8000, task ffff883d2f49caa0)
Stack:
 ffff8825a19d9ee8 0000000000000286 ffff883ff08d6ad8 ffffffff8118ef80
<d> ffff8825a19d9f38 ffff883ff08d6a40 ffff883ff37f9720 ffff883ff1b34800
<d> ffff8825a19d9f38 ffffffff8118ef80 ffff883ff37f9720 ffff883ff37f9668
Call Trace:
 [<ffffffff8118ef80>] ? filldir+0x0/0xe0
 [<ffffffff8118ef80>] ? filldir+0x0/0xe0
 [<ffffffff8118f200>] vfs_readdir+0xc0/0xe0
 [<ffffffff8117b0f2>] ? vfs_write+0x132/0x1a0
 [<ffffffff8118f389>] sys_getdents+0x89/0xf0
 [<ffffffff8100b0f2>] system_call_fastpath+0x16/0x1b
Code: 48 83 f8 02 4d 8d 7e 08 48 89 55 c8 0f 84 15 01 00 00 49 8b 5e 08 48 3b 5d c8 0f 85 7c 00 00 00 e9 da 00 00 00 66 90 48 8b 40 10 <4c> 8b 40 40 44 0f b7 49 44 4c 89 ee 49 8b 4c 24 40 48 8b 7d c0 
RIP  [<ffffffffa0274444>] configfs_readdir+0xf4/0x230 [configfs]
 RSP <ffff8825a19d9e78>
CR2: 0000000000000040

Environment

  • Red Hat Enterprise Linux (RHEL) 6
  • configfs (typically used by clustering software)

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