Kernel panic in SMB2_sess_setup() after a CIFS filesystem got disconnected

  • 7023105
  • 18-Jun-2018
  • 12-Dec-2018

Environment

SUSE Linux Enterprise Server 12 Service Pack 2 (SLES 12 SP2)
SUSE Linux Enterprise Server 12 Service Pack 3 (SLES 12 SP3)

Situation

A kernel panic may happen if a CIFS filesystem is disconnected as the SMB server got rebooted.
A typical stack trace of the failing task looks like:

PID: 6705   TASK: ffff88003680c8c0  CPU: 1   COMMAND: "kworker/1:0"
#0 [ffff88012ad4f9c0] machine_kexec at ffffffff81058fdc
#1 [ffff88012ad4fa10] __crash_kexec at ffffffff8111782a
#2 [ffff88012ad4fad0] crash_kexec at ffffffff811178fc
#3 [ffff88012ad4fae0] oops_end at ffffffff8101a604
#4 [ffff88012ad4fb00] no_context at ffffffff81066e77
#5 [ffff88012ad4fb50] __do_page_fault at ffffffff81067975
#6 [ffff88012ad4fbb8] do_page_fault at ffffffff81067dcb
#7 [ffff88012ad4fbe0] page_fault at ffffffff81619402
[exception RIP: SMB2_sess_setup+0x3a8]
RIP: ffffffffa04b4a88 RSP: ffff88012ad4fc98 RFLAGS: 00010296
RAX: 000000000000005b RBX: ffff8800af1ea000 RCX: ffffea0002d4a620
RDX: 000000000000005c RSI: ffff8800b5d62ac0 RDI: 0000000000000000
RBP: ffff88012ad4fd40 R8: 0000000000000000 R9: 000001c90d5987d6
R10: 000001c90d5987d6 R11: 0000000000000000 R12: 0000000000000000
R13: 00000000fffffff5 R14: ffff8800af3d6800 R15: 0000000000000001
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
#8 [ffff88012ad4fd48] cifs_setup_session at ffffffffa0487c8d [cifs]
#9 [ffff88012ad4fd70] smb2_reconnect at ffffffffa04b3e0c [cifs]
#10 [ffff88012ad4fde8] smb2_reconnect_server at ffffffffa04b6b40 [cifs]
#11 [ffff88012ad4fe38] process_one_work at ffffffff810989e4
#12 [ffff88012ad4fe78] worker_thread at ffffffff810995c6
#13 [ffff88012ad4fed0] kthread at ffffffff8109ead9
#14 [ffff88012ad4ff50] ret_from_fork at ffffffff81616505

Resolution

A patch has been issued for the bug in the cifs module.

If the latest kernel cannot be installed, please install one of the kernels listed below (or newer) to apply the patch.

SLES12 SP2 LTSS: 4.4.121-92.92.1
SLES12 SP3: 4.4.143-94.47.1

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