September 2016 - kernelnewbies@kernelnewbies.org

How to disable building of -dbg Debian package?
by Aleksander Alekseev Sept. 30, 2016

Sept. 30, 2016

Hello. I'm building Linux kernel like this: ``` cp /boot/config-$(uname -r) ./.config make olddefconfig make -j4 deb-pkg LOCALVERSION=-custom ``` Resulting files are (for 4.7.0 kernel): ``` 966694 linux-firmware-image-4.7.0-custom_4.7.0-custom-1_amd64.deb 10316460 linux-headers-4.7.0-custom_4.7.0-custom-1_amd64.deb 45639036 linux-image-4.7.0-custom_4.7.0-custom-1_amd64.deb 471400164 linux-image-4.7.0-custom-dbg_4.7.0-custom-1_amd64.deb 851664 linux-libc-dev_4.7.0-custom-1_amd64.deb ``` Compilation takes about an hour and most of this time is spent on creating a -dbg package which I don't install anyway. Frankly I don't think this package is very useful since Linux kernel can't be built with -O0 option [1]. Is it possible to disable building of this package? [1] https://lists.kernelnewbies.org/pipermail/kernelnewbies/2016-August/016687.… -- Best regards, Aleksander Alekseev

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problem init_mm undefined on arm
by Oscar Salvador Sept. 30, 2016

Sept. 30, 2016

Hi! While testing a module on arm platforms, I got an error which disturbed me. In my module I'm using pgd_offset_k [ http://lxr.free-electrons.com/source/arch/x86/include/asm/pgtable.h#L720] and this macro is working for x86 and x86_64. For arm platforms this macro is also defined here: http://lxr.free-electrons.com/source/arch/arm/include/asm/pgtable.h#L182 but I get this error while compiling the module on arm board: WARNING: "init_mm" [module] undefined! init_mm is first defined in http://lxr.free-electrons.com/source/mm/init-mm.c#L16 and then "exported" in http://lxr.free-electrons.com/source/include/linux/sched.h#L2558 (I'm including this header) Anyone knows how could I use pgd_offset_k in my module running on arm? Thank you very much

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Sending Patches using official Mail id
by Raul Piper Sept. 29, 2016

Sept. 29, 2016

Hi, How can I send the patches to the kernel mainline using official mail id using git-send? I am using microsoft exchange server and outlook as a client.What configuration i have to do on my linux or WIndows PC development machine. I have read about the IMAP configuration but not sure how to achieve it.Can someone please post the full details. Documentation/email-client.txt doesn't talk anything about the Microsoft Exchange server. Or using my gmail id would be the last resort? Thanks in advance ! Regards, Rp

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Re: Sending Patches using official Mail id
by Raul Piper Sept. 29, 2016

Sept. 29, 2016

On Fri, Sep 30, 2016 at 12:37 AM, Giedrius Statkevičius <giedrius.statkevicius(a)gmail.com> wrote: > On Thu, Sep 29, 2016 at 10:02 PM, Raul Piper <raulpblooper(a)gmail.com> wrote: >> Hi, >> How can I send the patches to the kernel mainline using official mail >> id using git-send? >> I am using microsoft exchange server and outlook as a client.What >> configuration i have to do on my linux or WIndows PC development >> machine. >> I have read about the IMAP configuration but not sure how to achieve >> it.Can someone please post the full details. >> Documentation/email-client.txt doesn't talk anything about the >> Microsoft Exchange server. >> Or using my gmail id would be the last resort? >> Thanks in advance ! >> Regards, >> Rp >> > (oops, replying to all now) > > `git send-email` is very handy. I think you should read the corresponding > manual page. It even has nice, very relevant examples to you as a kernel > developer. have you tried it using a corporate email id not the gmail id? which Exchange server you have used?You do it on windows or linux?

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insmod failing to insert a simple module
by Madhu K Sept. 29, 2016

Sept. 29, 2016

Hi All, While inserting a kernel module, insmod is failing with following error. insmod: error inserting 'page_walk.ko': Invalid module format. I verified the modinfo of "page_walk.ko" it is showing version magic as : 4.0.5_rc7+ SMP mod_unload modversions 686 what does "mod_unload" mean here? Thanks, Madhu

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My recent spam on the lists.
by Raymond Jennings Sept. 29, 2016

Sept. 29, 2016

I don't know why but claws decided to crap itself and spam everyone with half-typed versions of the same message. My internet was flaking out at the time too. Anyone know what happened, and any ideas for a more stable client that doesn't half-ass a message in multiple spammy chunks? Also, is it anything to do with gmail's SMTP?

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CodingStyle indentation and alignment
by Laurence Rochfort Sept. 27, 2016

Sept. 27, 2016

Hi all, I've read Documentation/CodingStyle and it states to use 8 character tabs. Reading several USB driver files including drivers/usb/usb-skeleton.c, I see that multi-line lists of argument and operands are often aligned on top of each other using a mixture of tabs and spaces. checkpatch doesn't complain about the mixture. For instance from usb-skeleton.c: static int skel_probe(struct usb_interface *interface, const struct usb_device_id *id) uses two tabs and 6 spaces, not just tabs like: static int skel_probe(struct usb_interface *interface, const struct usb_device_id *id) or static int skel_probe(struct usb_interface *interface, const struct usb_device_id *id) Is a mixture of tabs and spaces acceptable if it enhances readability? If not, which of the tabs-only forms is correct? Similarly, what about assignment alignment in structs? Cheers, Laurence.

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Scheduling of interrupt
by Er Krishna Sept. 27, 2016

Sept. 27, 2016

Hi All, I am asking below question for understanding. Pls help me to understand this: 1. How does APIC schedule interrupt on particular core ? How does Apic takes a decision that first few interrupt will be schedule on Core 0 and remaining for load balancing will be schedule on different core ? What are the advantage of scheduling interrupt always on core 0 w.r.t Cache hot and all ? 2. Is it possible that incoming interrupt can be scheduled on particular core rather than core 0 ? What is the configuration option or api is available for that inside kernel or in user space ? Thanks, Krishna

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kmem_cache not showing in /proc/slabinfo
by becher.jannik＠gmail.com Sept. 27, 2016

Sept. 27, 2016

Hi All, I played a little bit around with kmem_cache_alloc() and kmem_cache_create() and figured out that it only appears in /proc/slabinfo if I reserve a specific amount of memory. Isn't it always preferable to precache space for often used structs even for small structs? I'm not sure whether I understood it right how it works. But how does the kernel know for how many structs he should preallocate memory? Best regards Jannik Becher

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Realtek datasheets - R8168
by Prabhunath G Sept. 26, 2016

Sept. 26, 2016

Hi All, I have R8168 card and I am trying to analyze the code and got stuck at one point. Can any one help me in getting R8168 data sheet. Regards, Prabhunath G Linux Trainer Bangalore

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