June 2014 - kernelnewbies@kernelnewbies.org - Kernelnewbies Mailing Lists

Build error while building Linux Kernel 3.4
by Dipanjan Das June 3, 2014

June 3, 2014

Hi. I tried building Linux Kernel 3.4 from the source on Ubuntu 10.04 (Linux LAPTOP 2.6.32-21-generic #32-Ubuntu), gcc 4.4.3 on Intel processor. Here's the output: make[1]: Nothing to be done for `all'. make[1]: Nothing to be done for `relocs'. CHK include/linux/version.h CHK include/generated/utsrelease.h CALL scripts/checksyscalls.sh CHK include/generated/compile.h UPD include/generated/compile.h CC init/version.o LD init/built-in.o CC arch/x86/kernel/signal.o arch/x86/kernel/signal.c:260: error: ‘__NR_sigreturn’ undeclared here (not in a function) arch/x86/kernel/signal.c:271: error: ‘__NR_rt_sigreturn’ undeclared here (not in a function) arch/x86/kernel/signal.c: In function ‘do_signal’: arch/x86/kernel/signal.c:798: error: ‘__NR_restart_syscall’ undeclared (first use in this function) arch/x86/kernel/signal.c:798: error: (Each undeclared identifier is reported only once arch/x86/kernel/signal.c:798: error: for each function it appears in.) make[2]: *** [arch/x86/kernel/signal.o] Error 1 make[1]: *** [arch/x86/kernel] Error 2 make: *** [arch/x86] Error 2

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Getting unregister_netdevice: waiting for eth0 to become free. Usage count = 4 error
by Vishwas Srivastava June 3, 2014

June 3, 2014

Hi All, When i am trying to delete an interface from the application, while traffic is flowing through it, kernel throws the message unregister_netdevice: waiting for eth0 to become free. Usage count = 4 which means network device usage counter is more that zero and there are 4 references of this device still active, therefore the networking subsystem of the kernel defers it, to become the usage counter 0. Can somebody let me know what are the operations/ events increases the reference count of any network device. I looked in to the kernel code and found that a call to "dev_hold" increases the refrence count and "dev_put" decreases this. thanks, Vishwas S

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Question regarding ISA DMA
by Pranay Srivastava June 3, 2014

June 3, 2014

Hi, I'm trying to understand how to use the ISA DMA with my PC. What I'm not able to understand is that why is it required to have an IRQ line associated with my device that is going to initiate the DMA? As I understand DMA controller would be signalling CPU[Correct?] so this IRQ would be handled by the ISA api? [Correct?]. What I don't understand is that how the device would know that DMA has been completed since device already has offloaded that work to DMA controller so why is it required to have an IRQ for the device? OR is it that I need to request_irq for DMA controller? Totally confused at this point. -- ---P.K.S

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head.S
by Saurabh Jain June 3, 2014

June 3, 2014

hello every one ! I am trying to trace Linux kernel booting process for ARM architecture. Right now i am doing it manually . I am getting problem in reading assembly codes (like in head.s and other files) . Can any body tell me the correct way of tracing the linux kernel booting process ? Is there any guide which perfectly document Linux kernel files function by function ? Thank You!

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Information regarding Device Tree
by JAYESH TANK June 3, 2014

June 3, 2014

Hi All, I would like to write script to get Windows Device Manager like functionality to check all the devices present on my Linux machine. What all are the ways to get about this, is iterating sysfs is the way? Or is there any other elegant way? Thanks for support. Jayesh Kumar

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Linux reboot command takes too long
by Vipul Jain June 3, 2014

June 3, 2014

Hi All, I have a quick question on Linux reboot: On my system I have /var/core directory created which has 300G space and if I fill the /var/core with files say upto 290G and reboot the system and after it comes up and delete the files in /var/core and try to reboot the system takes 45 mins before it actually reboots. Wondering if anyone has seen this before and what could be the issue? Regards, Vipul.

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Newbie task: Fix a build regression
by Richard Weinberger June 2, 2014

June 2, 2014

Hi! On linux-next (next-20140530) the UML out-of-tree build is broken. ---cut--- rw@azrael:~/linux-next (next-20140530)> make defconfig ARCH=um O=/mnt/o GEN ./Makefile *** Default configuration is based on 'x86_64_defconfig' # # configuration written to .config # rw@azrael:~/linux-next (next-20140530)> LANG=C make -j 8 linux ARCH=um O=/mnt/o CHK include/generated/uapi/linux/version.h CHK include/config/kernel.release GEN ./Makefile Using /home/rw/linux-next as source for kernel CHK include/generated/utsrelease.h UPD include/generated/utsrelease.h CC arch/x86/um/user-offsets.s /home/rw/linux-next/arch/x86/um/user-offsets.c:21:29: fatal error: asm/syscalls_64.h: No such file or directory compilation terminated. make[2]: *** [arch/x86/um/user-offsets.s] Error 1 make[1]: *** [arch/x86/um/user-offsets.s] Error 2 make: *** [sub-make] Error 2 ---cut--- Fixing this should be easy, so I offer this as a newbie task. 1. Find out which commit broke the build (i.e. using git bisect) 2. Fix the build 3. Send me a patch -- Thanks, //richard

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Linux Hibernation with sata driver
by AYAN KUMAR HALDER June 2, 2014

June 2, 2014

Hi, I am working with Linux hibernation framework on ARM based custom SOC which has SATA controller on PCI bus. I see that when the system resumes from hibernation, the SATA controller(drivers/ata/ahci.c) on PCI bus fails to come up. My understanding is that the hibernation calls 'freeze' of all devices. The SATA controller receives the power state event as PM_EVENT_FREEZE ( ie pdev->dev.power.power_state.event = PM_EVENT_FREEZE). Thus when system restores the hibernation image, ahci_pci_device_resume gets called in which ahci_pci_reset_controller/ahci_pci_init_controller does not get called. So SATA controller fails to come up. Please let me know if my understanding is correct or not. If so, then in ahci_pci_device_resume() should we change the following if (pdev->dev.power.power_state.event == PM_EVENT_SUSPEND) to if (pdev->dev.power.power_state.event == PM_EVENT_FREEZE) In hibernation , as we power down the system, so I understand that the sata controller need to be reset and re-initialized for proper functioning. Regards, Ayan Kumar Halder

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Setting the skb->mark field from application
by Vishwas Srivastava June 2, 2014

June 2, 2014

Hi all, Is it possible to set the skb->mark flied of the linux socket buffer from the application? Suppose application is using the Raw socket of Ethernet interface and it sends and receive packets to that interface. However, application wants to set the skb->mark filed of the socket buffer which in turn is honoured by the ethernet driver. I could not find any option in the api "setsockopt" which will allow to set the skb->mark field. Anybody having any idea if it can be done from the application? thanks, Vishwas S

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get_user() and put_user() missing in syscall list
by Dipanjan Das June 2, 2014

June 2, 2014

Hi, Here's an exhaustive list <http://man7.org/linux/man-pages/man2/syscalls.2.html> of Linux syscall, but I can't find get_user() and put_user() API. Why is it so? What am I missing?

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