Re: kernel loglevel
Hi Joel, It works by specifying ccflags-y += -DDEBUG in the Makefile. Thank you for the info Cheers, Wenda Ni, Ph.D. On Mon, Oct 17, 2016 at 7:48 PM, Joel Fernandes wrote: > Hi Wenda, > > pr_debug needs you to define the DEBUG macro to activate it. > > Check: > http://stackoverflow.com/questions/28936199/pr-debug-not-giving-any-output > > and the kernel docs, > https://www.kernel.org/doc/local/pr_debug.txt > > Joel > > On Mon, Oct 17, 2016 at 4:17 PM, Wenda Ni wrote: > > Dear all, > > > > I am working on a kernel module that incorporate both pr_debug and > > pr_warn. I would like to see pr_debug messages from dmesg. > > > > What I followed is to specify kernel parameter by saying "loglevel=7". > > This can be seen confirmed from /proc/cmdline. But still, I donot get > > pr_debug level messages either from dmesg or from /var/log/messages. I > > also tried echo 7 > /proc/sys/kernel/printk. It does not return what I > > expect, either. > > > > Let me know what I am missing. Thank you very much in advance. > > > > Cheers, > > > > Wenda Ni, Ph.D. > > > > ___ > > Kernelnewbies mailing list > > Kernelnewbies@kernelnewbies.org > > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: kernel loglevel
On Mon, Oct 17, 2016 at 07:17:32PM -0400, Wenda Ni wrote: > Dear all, > > I am working on a kernel module that incorporate both pr_debug and > pr_warn. I would like to see pr_debug messages from dmesg. > > What I followed is to specify kernel parameter by saying "loglevel=7". > This can be seen confirmed from /proc/cmdline. But still, I donot get > pr_debug level messages either from dmesg or from /var/log/messages. I > also tried echo 7 > /proc/sys/kernel/printk. It does not return what I > expect, either. > > Let me know what I am missing. Thank you very much in advance. > > Cheers, > > Wenda Ni, Ph.D. > > ___ > Kernelnewbies mailing list > Kernelnewbies@kernelnewbies.org > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies Hello Wenda, I encountered the same issue a while ago. As stated here: http://elinux.org/Debugging_by_printing pr_debug is replaced with an empty statement unless the kernel is compiled with DEBUG. So if you just want to play with printing kernel debug logs, just define the DEBUG macro in your module source file for testing. I also observed that without a new line character at the end of the string passed to pr_debug, I could not find the log line in dmesg output. Not sure where this comes from. -- Thibaut SAUTEREAU signature.asc Description: PGP signature ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: kernel loglevel
Hi Wenda, pr_debug needs you to define the DEBUG macro to activate it. Check: http://stackoverflow.com/questions/28936199/pr-debug-not-giving-any-output and the kernel docs, https://www.kernel.org/doc/local/pr_debug.txt Joel On Mon, Oct 17, 2016 at 4:17 PM, Wenda Ni wrote: > Dear all, > > I am working on a kernel module that incorporate both pr_debug and > pr_warn. I would like to see pr_debug messages from dmesg. > > What I followed is to specify kernel parameter by saying "loglevel=7". > This can be seen confirmed from /proc/cmdline. But still, I donot get > pr_debug level messages either from dmesg or from /var/log/messages. I > also tried echo 7 > /proc/sys/kernel/printk. It does not return what I > expect, either. > > Let me know what I am missing. Thank you very much in advance. > > Cheers, > > Wenda Ni, Ph.D. > > ___ > Kernelnewbies mailing list > Kernelnewbies@kernelnewbies.org > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: kernel loglevel
Thank you so much, Thibaut. I have spotted the source-code logic in include/linux/prink.h Cheers, Wenda Ni, Ph.D. On Mon, Oct 17, 2016 at 7:41 PM, Thibaut SAUTEREAU < thibaut.sauter...@telecom-sudparis.eu> wrote: > On Mon, Oct 17, 2016 at 07:17:32PM -0400, Wenda Ni wrote: >> Dear all, >> >> I am working on a kernel module that incorporate both pr_debug and >> pr_warn. I would like to see pr_debug messages from dmesg. >> >> What I followed is to specify kernel parameter by saying "loglevel=7". >> This can be seen confirmed from /proc/cmdline. But still, I donot get >> pr_debug level messages either from dmesg or from /var/log/messages. I >> also tried echo 7 > /proc/sys/kernel/printk. It does not return what I >> expect, either. >> >> Let me know what I am missing. Thank you very much in advance. >> >> Cheers, >> >> Wenda Ni, Ph.D. >> >> ___ >> Kernelnewbies mailing list >> Kernelnewbies@kernelnewbies.org >> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > > Hello Wenda, > > I encountered the same issue a while ago. > As stated here: http://elinux.org/Debugging_by_printing > pr_debug is replaced with an empty statement unless the kernel is compiled > with DEBUG. So if you just want to play with printing kernel debug logs, > just define the DEBUG macro in your module source file for testing. > > I also observed that without a new line character at the end of the string > passed to pr_debug, I could not find the log line in dmesg output. Not sure > where this comes from. > > -- > Thibaut SAUTEREAU ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
