SysRq: print hotkey info while pressing undef key
PATCH 1/1 SysRq: print hotkey info while pressing undef key
For SysRq, we just can get hot key list from Documentation/sysrq.txt , but in the most of cases, the user can't access it by hand on using SysRq to debug, so it is better for SysRq to provide an online help for the users.
SysRq has already provided a similiar help before this patch, but it is not so definite that the user doesn't know what happened and how to do on pressing an undefined hot key.
In addition, that funtion has a big loop with another big loop embedded which is very inefficient, it is intended to skip some hot key help info for such a function as "Changing Loglevel", just print a help info for this, that is very unnecessary. In fact, the key '0'
- '8' have different results the user should know.
This patch add this online help function, it'll print thw whole hot key list and corresponding function descriptions, it can print the new defined hot key without any changed needed.
The output is the below on pressing an undefined hot key:
SysRq : <6>this hot key isn't defined.
SysRq Help Information:
Hot Key Function Description =========== ==================== ALT+SysRq+0 Changing Loglevel to this value ALT+SysRq+1 Changing Loglevel to this value ALT+SysRq+2 Changing Loglevel to this value ALT+SysRq+3 Changing Loglevel to this value ALT+SysRq+4 Changing Loglevel to this value ALT+SysRq+5 Changing Loglevel to this value ALT+SysRq+6 Changing Loglevel to this value ALT+SysRq+7 Changing Loglevel to this value ALT+SysRq+8 Changing Loglevel to this value ALT+SysRq+9 Changing Loglevel to this value ALT+SysRq+a Not defined ALT+SysRq+b Resetting ALT+SysRq+c Trigger a crashdump ALT+SysRq+d Not defined ALT+SysRq+e Terminate All Tasks ALT+SysRq+f Manual OOM execution ALT+SysRq+g Not defined ALT+SysRq+h Not defined ALT+SysRq+i Kill All Tasks ALT+SysRq+j Not defined ALT+SysRq+k SAK ALT+SysRq+l Not defined ALT+SysRq+m Show Memory ALT+SysRq+n Nice All RT Tasks ALT+SysRq+o Power Off ALT+SysRq+p Show Regs ALT+SysRq+q Show Pending Timers ALT+SysRq+r Keyboard mode set to XLATE ALT+SysRq+s Emergency Sync ALT+SysRq+t Show State ALT+SysRq+u Emergency Remount R/O ALT+SysRq+v Not defined ALT+SysRq+w Show Blocked State ALT+SysRq+x Not defined ALT+SysRq+y Not defined ALT+SysRq+z Not defined
--- sysrq.c | 38 ++++++++++++++++++++++++++------------ 1 file changed, 26 insertions(+), 12 deletions(-)
drivers/char/sysrq.c +26 -12
@@ -45,6 +45,16 @@ int __read_mostly __sysrq_enabled = 1;static int __read_mostly sysrq_always_enabled; +/* +* Hot key table SysRq supports +*/ +static char __read_mostly sysrq_hot_key_table[36 ] = { +'0' ,'1' ,'2' ,'3' ,'4' ,'5' ,'6' ,'7' ,'8' ,'9' , +'a' ,'b' ,'c' ,'d' ,'e' ,'f' ,'g' ,'h' ,'i' ,'j' , +'k' ,'l' ,'m' ,'n' ,'o' ,'p' ,'q' ,'r' ,'s' ,'t' , +'u' ,'v' ,'w' ,'x' ,'y' ,'z' +}; +int sysrq_on (void ) {return __sysrq_enabled || sysrq_always_enabled;
@@ -81,7 +91,7 @@ static void sysrq_handle_loglevel(int kestatic struct sysrq_key_op sysrq_loglevel_op = { .handler = sysrq_handle_loglevel, .help_msg ="loglevel0-8" , - .action_msg ="Changing Loglevel" , + .action_msg ="Changing Loglevel to this value" , .enable_mask =SYSRQ_ENABLE_LOG , };
@@ -410,7 +420,7 @@ void __handle_sysrq(int key, struct tty_spin_lock_irqsave (&sysrq_key_table_lock, flags); orig_log_level = console_loglevel; console_loglevel =7 ; -printk (KERN_INFO "SysRq : " ); +printk (KERN_INFO "\nSysRq : " ); op_p =__sysrq_get_key_op (key);if (op_p) {
@@ -426,18 +436,22 @@ void __handle_sysrq(int key, struct tty_printk ("This sysrq operation is disabled.\n" ); } }else { -printk ("HELP : " ); -/* Only print the help msg once per handler */ +/* +* Print SysRq hot key list +*/ +printk (KERN_INFO "this hot key isn't defined.\n" ); +printk (KERN_INFO "\nSysRq Help Information:\n" ); +printk (KERN_INFO "\n Hot Key Function Description\n" ); +printk (KERN_INFO "=========== ====================\n" );for (i =0 ; i <ARRAY_SIZE (sysrq_key_table); i++) {if (sysrq_key_table[i]) { -int j; - -for (j =0 ; sysrq_key_table[i] != - sysrq_key_table[j]; j++) - ; -if (j != i) -continue ; -printk ("%s " , sysrq_key_table[i]->help_msg); +printk (KERN_INFO "ALT+SysRq+%c %s\n" , + sysrq_hot_key_table[i], + sysrq_key_table[i]->action_msg); + }else { +printk (KERN_INFO "ALT+SysRq+%c %s\n" , + sysrq_hot_key_table[i], +"Not defined" ); } }printk ("\n" );
Quoted 15 lines · Yi Yang
For SysRq, we just can get hot key list from
Documentation/sysrq.txt, but in the most of cases, the user can't access it by hand on using SysRq to debug, so it is better for SysRq to provide an online help for the users.SysRq has already provided a similiar help before this patch, but it is not so definite that the user doesn't know what happened and how to do on pressing an undefined hot key.
In addition, that funtion has a big loop with another big loop embedded which is very inefficient, it is intended to skip some hot key help info for such a function as "Changing Loglevel", just print a help info for this, that is very unnecessary. In fact, the key '0'
- '8' have different results the user should know.
Quoted 7 lines
This patch add this online help function, it'll print thw whole hot key list and corresponding function descriptions, it can print the new defined hot key without any changed needed.
The output is the below on pressing an undefined hot key:
SysRq : <6>this hot key isn't defined.
^^^
This is misplaced.
drivers/char/sysrq.c void __handle_sysrq(int key, struct tty_ · line 423
Quoted 6 lines
drivers/char/sysrq.c +1
-1@@ -410,7 +420,7 @@ void __handle_sysrq(int key, struct tty_spin_lock_irqsave (&sysrq_key_table_lock, flags); orig_log_level = console_loglevel; console_loglevel =7 ; -printk (KERN_INFO "SysRq : " ); +printk (KERN_INFO "\nSysRq : " );
It does not make any sense to put the printk level just before the newline, since the newline resets it to the default level.
Andreas.
Signature · 4 lines
Andreas Schwab, SuSE Labs, [email protected] SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany PGP key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 "And now for something completely different."
Hi!
Quoted 55 lines
For SysRq, we just can get hot key list from
Documentation/sysrq.txt, but in the most of cases, the user can't access it by hand on using SysRq to debug, so it is better for SysRq to provide an online help for the users.SysRq has already provided a similiar help before this patch, but it is not so definite that the user doesn't know what happened and how to do on pressing an undefined hot key.
In addition, that funtion has a big loop with another big loop embedded which is very inefficient, it is intended to skip some hot key help info for such a function as "Changing Loglevel", just print a help info for this, that is very unnecessary. In fact, the key '0'
- '8' have different results the user should know.This patch add this online help function, it'll print thw whole hot key list and corresponding function descriptions, it can print the new defined hot key without any changed needed.
The output is the below on pressing an undefined hot key:
SysRq : <6>this hot key isn't defined.
SysRq Help Information:
Hot Key Function Description =========== ==================== ALT+SysRq+0 Changing Loglevel to this value ALT+SysRq+1 Changing Loglevel to this value ALT+SysRq+2 Changing Loglevel to this value ALT+SysRq+3 Changing Loglevel to this value ALT+SysRq+4 Changing Loglevel to this value ALT+SysRq+5 Changing Loglevel to this value ALT+SysRq+6 Changing Loglevel to this value ALT+SysRq+7 Changing Loglevel to this value ALT+SysRq+8 Changing Loglevel to this value ALT+SysRq+9 Changing Loglevel to this value ALT+SysRq+a Not defined ALT+SysRq+b Resetting ALT+SysRq+c Trigger a crashdump ALT+SysRq+d Not defined ALT+SysRq+e Terminate All Tasks ALT+SysRq+f Manual OOM execution ALT+SysRq+g Not defined ALT+SysRq+h Not defined ALT+SysRq+i Kill All Tasks ALT+SysRq+j Not defined ALT+SysRq+k SAK ALT+SysRq+l Not defined ALT+SysRq+m Show Memory ALT+SysRq+n Nice All RT Tasks ALT+SysRq+o Power Off ALT+SysRq+p Show Regs ALT+SysRq+q Show Pending Timers ALT+SysRq+r Keyboard mode set to XLATE
Quoted 8 lines
ALT+SysRq+s Emergency Sync ALT+SysRq+t Show State ALT+SysRq+u Emergency Remount R/O ALT+SysRq+v Not defined ALT+SysRq+w Show Blocked State ALT+SysRq+x Not defined ALT+SysRq+y Not defined ALT+SysRq+z Not defined
This will scroll out of users view on small terminals.
Plus it is untrue. On sparc, it is stop+x, not sysrq+x.
drivers/char/sysrq.c int __read_mostly __sysrq_enabled = 1; · line 56
Quoted 9 lines
drivers/char/sysrq.c +9
-0+/* +* Hot key table SysRq supports +*/ +static char __read_mostly sysrq_hot_key_table[36 ] = { +'0' ,'1' ,'2' ,'3' ,'4' ,'5' ,'6' ,'7' ,'8' ,'9' , +'a' ,'b' ,'c' ,'d' ,'e' ,'f' ,'g' ,'h' ,'i' ,'j' , +'k' ,'l' ,'m' ,'n' ,'o' ,'p' ,'q' ,'r' ,'s' ,'t' , +'u' ,'v' ,'w' ,'x' ,'y' ,'z' +};
Plus this is practically guaranteed to get out of sync with reality. If you did this to make sysrq printing faster... then that is very bad optimization.
Pavel
Signature · 2 lines
(english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
Quoted 22 lines · Andreas Schwab
Quoted 19 lines · Yi Yang
For SysRq, we just can get hot key list from
Documentation/sysrq.txt, but in the most of cases, the user can't access it by hand on using SysRq to debug, so it is better for SysRq to provide an online help for the users.SysRq has already provided a similiar help before this patch, but it is not so definite that the user doesn't know what happened and how to do on pressing an undefined hot key.
In addition, that funtion has a big loop with another big loop embedded which is very inefficient, it is intended to skip some hot key help info for such a function as "Changing Loglevel", just print a help info for this, that is very unnecessary. In fact, the key '0'
- '8' have different results the user should know.This patch add this online help function, it'll print thw whole hot key list and corresponding function descriptions, it can print the new defined hot key without any changed needed.
Quoted 8 lines
Quoted 4 lines
The output is the below on pressing an undefined hot key:
SysRq : <6>this hot key isn't defined.
^^^This is misplaced.
printk(KERN_INFO "SysRq : \n") can fix it.
Quoted 12 lines
drivers/char/sysrq.c void __handle_sysrq(int key, struct tty_ · line 424
Quoted 8 lines
drivers/char/sysrq.c +1
-1@@ -410,7 +420,7 @@ void __handle_sysrq(int key, struct tty_spin_lock_irqsave (&sysrq_key_table_lock, flags); orig_log_level = console_loglevel; console_loglevel =7 ; -printk (KERN_INFO "SysRq : " ); +printk (KERN_INFO "\nSysRq : " );It does not make any sense to put the printk level just before the newline, since the newline resets it to the default level.
Thank you, I'll remove \n.
Quoted 3 lines
Andreas.
Quoted 68 lines · Pavel Machek
Hi!
Quoted 55 lines
For SysRq, we just can get hot key list from
Documentation/sysrq.txt, but in the most of cases, the user can't access it by hand on using SysRq to debug, so it is better for SysRq to provide an online help for the users.SysRq has already provided a similiar help before this patch, but it is not so definite that the user doesn't know what happened and how to do on pressing an undefined hot key.
In addition, that funtion has a big loop with another big loop embedded which is very inefficient, it is intended to skip some hot key help info for such a function as "Changing Loglevel", just print a help info for this, that is very unnecessary. In fact, the key '0'
- '8' have different results the user should know.This patch add this online help function, it'll print thw whole hot key list and corresponding function descriptions, it can print the new defined hot key without any changed needed.
The output is the below on pressing an undefined hot key:
SysRq : <6>this hot key isn't defined.
SysRq Help Information:
Hot Key Function Description =========== ==================== ALT+SysRq+0 Changing Loglevel to this value ALT+SysRq+1 Changing Loglevel to this value ALT+SysRq+2 Changing Loglevel to this value ALT+SysRq+3 Changing Loglevel to this value ALT+SysRq+4 Changing Loglevel to this value ALT+SysRq+5 Changing Loglevel to this value ALT+SysRq+6 Changing Loglevel to this value ALT+SysRq+7 Changing Loglevel to this value ALT+SysRq+8 Changing Loglevel to this value ALT+SysRq+9 Changing Loglevel to this value ALT+SysRq+a Not defined ALT+SysRq+b Resetting ALT+SysRq+c Trigger a crashdump ALT+SysRq+d Not defined ALT+SysRq+e Terminate All Tasks ALT+SysRq+f Manual OOM execution ALT+SysRq+g Not defined ALT+SysRq+h Not defined ALT+SysRq+i Kill All Tasks ALT+SysRq+j Not defined ALT+SysRq+k SAK ALT+SysRq+l Not defined ALT+SysRq+m Show Memory ALT+SysRq+n Nice All RT Tasks ALT+SysRq+o Power Off ALT+SysRq+p Show Regs ALT+SysRq+q Show Pending Timers ALT+SysRq+r Keyboard mode set to XLATEQuoted 9 lines
ALT+SysRq+s Emergency Sync ALT+SysRq+t Show State ALT+SysRq+u Emergency Remount R/O ALT+SysRq+v Not defined ALT+SysRq+w Show Blocked State ALT+SysRq+x Not defined ALT+SysRq+y Not defined ALT+SysRq+z Not defined
Quoted 5 lines
This will scroll out of users view on small terminals.
Plus it is untrue. On sparc, it is stop+x, not sysrq+x.
You're right, it it better to remove ALT+SysRq
Quoted 7 lines
Quoted 7 lines
drivers/char/sysrq.c +7
-0+/* +* Hot key table SysRq supports +*/ +static char __read_mostly sysrq_hot_key_table[36 ] = { +'0' ,'1' ,'2' ,'3' ,'4' ,'5' ,'6' ,'7' ,'8' ,'9' , +'a' ,'b' ,'c' ,'d' ,'e' ,'f' ,'g' ,'h' ,'i' ,'j' , +'k' ,'l' ,'m' ,'n' ,'o' ,'p' ,'q' ,'r' ,'s' ,'t' ,
Quoted 9 lines
drivers/char/sysrq.c int __read_mostly __sysrq_enabled = 1; · line 56
Quoted 3 lines
drivers/char/sysrq.c +2
-0+ 'u', 'v', 'w', 'x', 'y', 'z' +};Plus this is practically guaranteed to get out of sync with reality. If you did this to make sysrq printing faster... then that is very bad optimization.
Pavel
This char array is just for output, thees are jsut the keys sysrq has defined, in the current design of sysrq, to add a new key is not easy unless you use an existed but unused key, so this has no problem.
SysRq is just for debugging or emergent handling, so this array is impossible to result in any bad effects, it is just for convenience.