DLm: Unexpected VTE Reboot with DLmV0199E and btifc Driver Error
Summary: An unexpected reboot of the VTE may occur, typically generating a ConnectHome event (DLmV0199E) and a core dump. This issue has been observed in DLm 5.5.0.4 Hotfix 2, and may also affect DLm 5.5.0.4 Hotfix 1. ...
Symptoms
The VTE may reboot without warning.
In ConnectHome, the following event may be reported: DLmV0199E – VTE unexpectedly restarted without a clean shutdown.
In /var/log/messages, entries similar to the following may be observed:
2025-09-23T18:14:35.718486-07:00 vte2 kernel: [37095220.390346] INFO: rcu_sched self-detected stall on CPU
2025-09-23T18:14:35.718502-07:00 vte2 kernel: [37095220.390351] 17-...: (15000 ticks this GP) idle=e46/140000000000001/0 softirq=1383296613/1383296613 fqs=7429
2025-09-23T18:14:35.718504-07:00 vte2 kernel: [37095220.390351] (t=15001 jiffies g=1259992788 c=1259992787 q=35986)
2025-09-23T18:14:35.718505-07:00 vte2 kernel: [37095220.390354] NMI backtrace for cpu 17
2025-09-23T18:14:35.718506-07:00 vte2 kernel: [37095220.390356] CPU: 17 PID: 19300 Comm: btifc_rxbufs/2 Tainted: G W OE 4.12.14-122.173-default #1 SLE12-SP5
2025-09-23T18:14:35.718525-07:00 vte2 kernel: [37095220.390357] Hardware name: Dell Inc. PowerEdge R740/0YWR7D, BIOS 2.19.1 06/04/2023
2025-09-23T18:14:35.718526-07:00 vte2 kernel: [37095220.390357] Call Trace:
2025-09-23T18:14:35.718526-07:00 vte2 kernel: [37095220.390359] <IRQ>
2025-09-23T18:14:35.718527-07:00 vte2 kernel: [37095220.390365] dump_stack+0x64/0x89
2025-09-23T18:14:35.718528-07:00 vte2 kernel: [37095220.390368] nmi_cpu_backtrace+0x98/0xa0
2025-09-23T18:14:35.718529-07:00 vte2 kernel: [37095220.390371] ? irq_force_complete_move+0x130/0x130
2025-09-23T18:14:35.718530-07:00 vte2 kernel: [37095220.390373] nmi_trigger_cpumask_backtrace+0xdd/0x120
.
2025-09-23T18:14:35.718551-07:00 vte2 kernel: [37095220.390413] ibtifc_ql_send_rx_buffers_thread+0x19/0x240 [btifc_commdrv]
Cause
A soft lockup in the FICON driver causes NMI trigger and reboot.
Resolution
This issue is resolved in DLm firmware version V5.5.0.6 and later.