Message not appearing in mesg
Dear all, I have a module that uses pr_debug at init. Although the module is successfully loaded, the message appears neither in dmesg, nor at the console. I tried toprint a 8 to /proc/sys/kernel/printk but that does not change anything. Any hint would be warmly appreciated. Thanks! Sébastien.
On 7 July 2015 at 15:53, Sébastien Hinderer <Sebastien.Hinderer@ens-lyon.org
wrote:
Dear all,
I have a module that uses pr_debug at init. Although the module is successfully loaded, the message appears neither in dmesg, nor at the console. I tried toprint a 8 to /proc/sys/kernel/printk but that does not change anything.
Any hint would be warmly appreciated.
Thanks!
Sébastien
Do you have the relevant DEBUG macros activated in your kernel's configuration? https://www.kernel.org/doc/local/pr_debug.txt http://elinux.org/Debugging_by_printing If not, activate them. Or if in a pinch, switch to using pr_alert() for development. Luis
Hi Luis, Many thanks for your prompt and helpfulresponse!
Do you have the relevant DEBUG macros activated in your kernel's configuration?
Perhaps not...
Read this, thanks. But that has nothing to do with KConfigmacros, has it?
http://elinux.org/Debugging_by_printing
If not, activate them. Or if in a pinch, switch to using pr_alert() for development.
What surprises me is that I made sue the message appears inthe .ko file and it was there,whereas it seems pr_debug discards its argument at compile time. Or is it at execution time? Thanks! Sébastien.
On 7 July 2015 at 16:11, Sébastien Hinderer <Sebastien.Hinderer@ens-lyon.org
wrote:
Hi Luis,
Many thanks for your prompt and helpfulresponse!
Do you have the relevant DEBUG macros activated in your kernel's configuration?
Perhaps not...
Read this, thanks. But that has nothing to do with KConfigmacros, has it?
http://elinux.org/Debugging_by_printing
If not, activate them. Or if in a pinch, switch to using pr_alert() for development.
What surprises me is that I made sue the message appears inthe .ko file and it was there,whereas it seems pr_debug discards its argument at compile time. Or is it at execution time?
Thanks!
Sébastien
Compile time. pr_debug() is meant only for development and discarded for "production" builds. pr_debug(), which is ordinarily an empty macro that discards its arguments at compile time. To enable debugging output, build the appropriate file with -DDEBUG by adding CFLAGS_[filename].o := -DDEBUG That is the key part there. But it is good to also check the options you have in: make menuconfig-> Kernel Hacking Enjoy, Luis
participants (3)
-
Luis de Bethencourt -
Shérab -
Sébastien Hinderer