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Cisco Bug: CSCul05056 - SYS-6-STACKLOW due to NBAR config

Last Modified

May 28, 2020

Products (74)

  • Cisco IOS
  • Cisco 1905 Serial Integrated Services Router
  • Cisco 819 Hardened Integrated Services Router
  • Cisco C897VA Integrated Services Router
  • Cisco 886VAG 3G Integrated Services Router
  • Cisco VG204XM Analog Voice Gateway
  • Cisco 2951 Integrated Services Router
  • Cisco 861W Integrated Services Router
  • Cisco C892FSP Integrated Services Router
  • Cisco 892W Integrated Services Router
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Known Affected Releases

15.0(1)M3 15.3(3)M 15.4(0.4)T

Description (partial) 

Symptom:
A Cisco router may crash when configuring NBAR or any other feature which enables NBAR internally. In the crash log file, the crash will be shown as a STACKLOW condition. Examples of this are:

%SYS-6-STACKLOW: Stack for process Config Probe running low, 0/12000
%SYS-6-STACKLOW: Stack for process SSH Process running low, 0/12000
%SYS-6-STACKLOW: Stack for process InitializeNbarAPI running low, 0/12000

Conditions:
This crash is triggered by enabling NBAR directly or indirectly through another feature. Two such examples are configuring NAT on an interface or configuring NBAR on an interface. For example:

(config)#interface gigabitethernet0/1
(config-if)#ip nbar protocol-discovery 

(config)#interface gigabitethernet0/1
(config-if)#ip nat inside

The router may not crash depending on how the configuration is done. For example configuring the feature over the console will not cause a crash. Configuring the feature over SSH, through FTP, Smart Install, etc though will cause the crash.

Related Community Discussions

Metro boot DHCP
Hi, I'm currently testing a Metro ME3400G-2CS-A, before we purchase new ones. It's completely up-to-date, but when I try to boot with config download from TFTP "boot host dhcp", the device crashes with warning: *Mar  1 00:01:32.517: %SYS-6-STACKLOW: Stack for process Boot HostDHCP running low, 0/6000 The config that he try's to download is only 57 line big and 1147 characters -_-'. Anyone any idea how to fix this? Kind regards, Ricardo Brock
Latest activity: Aug 11, 2016
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