From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux ia64; en-US; rv:1.5) Gecko/20031120 Firebird/0.7 Description of problem: sysrq+t only displays a header, it doesn't show any task tracebacks. this is connected to an hp rx5670 console via a telnet connection to the mp. sysrq + s works on this setup. [bigeverest:root]# cat /proc/sys/kernel/sysrq 0 [bigeverest:root]# echo 1 > /proc/sys/kernel/sysrq [bigeverest:root]# telnet> ? Commands may be abbreviated. Commands are: close close current connection logout forcibly logout remote user and close the connection display display operating parameters mode try to enter line or character mode ('mode ?' for more) open connect to a site quit exit telnet send transmit special characters ('send ?' for more) set set operating parameters ('set ?' for more) unset unset operating parameters ('unset ?' for more) status print status information toggle toggle operating parameters ('toggle ?' for more) slc set treatment of special characters z suspend telnet environ change environment variables ('environ ?' for more) telnet> send ? ao Send Telnet Abort output ayt Send Telnet 'Are You There' brk Send Telnet Break ec Send Telnet Erase Character el Send Telnet Erase Line escape Send current escape character ga Send Telnet 'Go Ahead' sequence ip Send Telnet Interrupt Process nop Send Telnet 'No operation' eor Send Telnet 'End of Record' abort Send Telnet 'Abort Process' susp Send Telnet 'Suspend Process' eof Send Telnet End of File Character synch Perform Telnet 'Synch operation' getstatus Send request for STATUS ? Display send options telnet> send brk SysRq : Emergency Sync Syncing device 08:14 ... OK Syncing device 08:12 ... OK Syncing device 08:13 ... OK Syncing device 08:21 ... OK Done. [bigeverest:root]# [bigeverest:root]# telnet> send brk SysRq : Show State Version-Release number of selected component (if applicable): 2.4.18-e.37smp How reproducible: Always Steps to Reproduce: 1. echo 1 > /proc/sys/kernel/sysrq 2. send a break + t over console 3. Actual Results: the following is displayed on the console: SysRq : Show State Expected Results: tracebacks of tasks on the system are displayed Additional info:
What is the output of: # echo /proc/sys/kernel/printk If I remember correctly, on AS2.1 for IA64, the default values are: 3 4 1 7 The first number is the console log level, and the second number is the default message level. When kernel printk's are issued without a specified message level preceding the output string (KERN_INFO, KERN_WARNING, KERN_ERR, etc.), then the printk function uses the second number above as the message level. Then, only if the console log level is greater than the the message level will the messages be printed to the console. The "Show State" string will be always be printed because the sysrq.c handler temporarily bumps the console log level to 7. But then it sets it back to its original value, and calls the code that prints out the back traces. Since those printks do not have a KERN_XXX at the beginning of each string, the level is set to the default message level. Therefore, if the first number (the console log level) is less than the default message level of 4, then the messages are not printed to the console -- but only go to the kernel's message buffer, and eventually to /var/log/messages. So if you do this: # echo 7 4 1 7 > /proc/sys/kernel/printk then the back trace code will be displayed. (The first number must be greater than the second, so "5" would work as well as "7" since it is greater than the default message level of "4")
> What is the output of: > > # echo /proc/sys/kernel/printk /proc/sys/kernel/printk :) > If I remember correctly, on AS2.1 for IA64, the default values are: > > 3 4 1 7 yes, that is correct. > So if you do this: > > # echo 7 4 1 7 > /proc/sys/kernel/printk > > then the back trace code will be displayed. (The first number must > be greater than the second, so "5" would work as well as "7" since > it is greater than the default message level of "4") yes, that worked. thank you Dave.