Bug 23731849 :: AFD causing hang at OS level due to rare race condition (Doc ID 2167007.1)

Last updated on JULY 30, 2016

Applies to:

Oracle Database - Enterprise Edition - Version 12.1.0.2 and later
Information in this document applies to any platform.

Symptoms

VM is hung very frequently. Sometimes the VM has high load, sometimes it
doesn't. After the VM is hung, no system log generated. Cannot ping or
connect to VM console.

OS level crashdump was configured which was used by AFD to dump the stack

The new core is hung on cpu 6:
.
==========
[986005.313840] NMI backtrace for cpu 6
[986005.313840] CPU: 6 PID: 9508 Comm: oracle_9508_cdb Tainted: P


[986005.313840] ffffffffa0503214 ffff88010c545068 ffff880a8fcc3ea8
ffffffffa050523b
[986005.313840] Call Trace:
[986005.313840] <IRQ>
[986005.313840]
[986005.313840] [<ffffffff810b0d33>] __wake_up+0x23/0x50
[986005.313840] [<ffffffffa0503214>] AfdgWakeupAll+0x24/0x30 [oracleafd]
[986005.313840] [<ffffffffa050523b>] afd_done_tasklet+0xab/0x110 [oracleafd]
.
[986005.313840] [<ffffffff810847fd>] tasklet_hi_action+0x7d/0x140
[986005.313840] [<ffffffff81084aef>] __do_softirq+0xef/0x280
[986005.313840] [<ffffffff8164735c>] call_softirq+0x1c/0x30
[986005.313840] [<ffffffff81016fc5>] do_softirq+0x65/0xa0
[986005.313840] [<ffffffff81084e85>] irq_exit+0x115/0x120
[986005.313840] [<ffffffff813a3d18>] xen_evtchn_do_upcall+0x38/0x50
[986005.313840] [<ffffffff816474ed>] xen_hvm_callback_vector+0x6d/0x80
[986005.313840] <EOI>
[986005.313840]
[986005.313840] [<ffffffff81645b6b>] ? sysret_audit+0x17/0x21
[986005.313840] Code: ba 00 00 02 00 f0 0f c1 17 89 d1 c1 e9 10 66 39 d1 75
05 4c 89 c0 5d c3 83 e1 fe 0f b7 f1 b8 00 80 00 00 0f b7 17 66 39 d1 74 e8
<f3> 90 83 e8 01 75 f1 0f 1f 80 00 00 00 00 eb e3 66 66 2e 0f 1f
==========
.

 

Cause

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