Calling a module method from inside the kernel - is it possible Inbox

Hi, all, I want to calling a module method (I am developing the module) from inside the kernel. How can I achieve it ? (BTW, I know that vice versa is possible by EXPORT_SYMBOL.) rgs, Kevin ___ Kernelnewbies mailing list

Question about applying a kernel patch with git am received from a mailing list

Hi, I am following some kernel mailing lists (netdev and others). I want to be able to save recent patches and to apply the against a git tree. I tried using MUTT client for this. I save the patch (which is almost always inline). Then I run git apply --check patchName and git apply patchName

Re: Question about applying a kernel patch with git am received from a mailing list

, Kevin Wilson wrote: Hi, I am following some kernel mailing lists (netdev and others). I want to be able to save recent patches and to apply the against a git tree. I tried using MUTT client for this. I save the patch (which is almost always inline). Then I run git apply --check patchName

Re: Question about applying a kernel patch with git am received from a mailing list

to save patches and then git am the patches without these error ? I heard that mutt is very popular for working with patches. Such a feature seems natural to me. rgs Kevin On Tue, Nov 20, 2012 at 8:02 PM, Josh Cartwright jo...@eso.teric.us wrote: On Tue, Nov 20, 2012 at 07:53:57PM +0200, Kevin Wilson

question about building a module

Hi, I am adding some code of my own **only** under net/bluetooth in some file there. There is only exactly one module which is changed by my addition, This is net/bluetooth/bluetooth.ko Now, when I run 'make -j2 modules' it takes quite a time, even If I did one change in one line in a file

misc device question

Hello,kernelnewbies I am trying to develop a misc driver in 3.7.0 kernel. As a basis I copy and paste this code, *without any change*, http://virtlog.com/2008/03/25/linux-miscdevice-sample/ And build it. after insmod I have : [root@n miscDevice]\ls -al /dev/mymisc crw--- 1 root root 10, 59

Re: misc device question

, Dec 19, 2012 at 10:36 AM, Kevin Wilson wkev...@gmail.com wrote: Hello,kernelnewbies I am trying to develop a misc driver in 3.7.0 kernel. As a basis I copy and paste this code, *without any change*, http://virtlog.com/2008/03/25/linux-miscdevice-sample/ And build it. after insmod I have

Question: copy_process() and CLONE_NEWNS

Hi all, question: In copy_process() we have: static struct task_struct *copy_process(unsigned long clone_flags, unsigned long stack_start, struct pt_regs *regs, unsigned

start address of the code segment of the program on x86-64

Hi, 0×08048000 address is the start address of the code segment of a program in on x86-32. What is the start address of the code segment of the program on x86-64 ? Is there a place in the kernel code where I can add a printk on a x86_64 machine to view the code segment start ? How can it be

Re: Beyond kernel-janitor

/ramirosen rgs Kevin Wilson On Fri, Feb 15, 2013 at 8:43 PM, Kumar amit mehta gmate.a...@gmail.com wrote: Hi All, After watching Greg's video on How to write and submit your first patch,the discussions that happened over kernel newbie mailing list and the assorted information scattered

Re: using prefetch

Thanks! KW On Fri, Feb 15, 2013 at 6:42 PM, mic...@michaelblizek.twilightparadox.com wrote: Hi! On 12:16 Fri 15 Feb , Kevin Wilson wrote: ... AFAIK, what prefetch does is get a variable from memory and put it in cache (L2 cache I believe). Yes, this is true. See: http://gcc.gnu.org

process 0 (swapper)

Hi, I see that the idle process (process 0) , is called swapper. init_idle() in kernel/sched/core.c: ... #if defined(CONFIG_SMP) sprintf(idle-comm, %s/%d, INIT_TASK_COMM, cpu); #endif ... #define INIT_TASK_COMM swapper in include/linux/init_task.h Two questions: 1) why does this #if

Re: process 0 (swapper)

Hi, we see this code in proc_pid_lookup: tgid = name_to_int(dentry); if (tgid == ~0U) goto out; In other words, if you ask for pid 0, it bails and doesn't return anything. Are you sure that this is what it cjecks? ~0U is not 0 but -1; for example, try:

Tracing - how can I know which method was called

Hi, I added a network event trace thus: echo 1 /sys/kernel/debug/tracing/events/net/net_dev_xmit/enable Afterwards I see many lines with net_dev_xmit in /sys/kernel/debug/tracing. Now, looking in the source code, I see that there are two calls to trace_net_dev_xmit() in

SIGKILL and a sleeping kernel module

Hi all, I am trying to send a SIGKILL to a kernel module which is sleeping. I added a printk after the sleep command. Sending a SIGLKILL (by kill -9 SIGLKILL pidOfKernelThread) does **not** yield the message from printk(calling do_exit\n); which is immediately after the msleep() command, as I

Re: SIGKILL and a sleeping kernel module

, Rgs, Kevin On Tue, Feb 19, 2013 at 1:38 PM, Srivatsa S. Bhat srivatsa.b...@linux.vnet.ibm.com wrote: On 02/19/2013 05:02 PM, Kevin Wilson wrote: Hi, Thanks about the info about ps. This raises two new questions: 1) The following code is a very basic kernel module (based on my previous

ptrace and kernel threads

H i all, You will get an error when trying to call ptrace system call on kernel threads. In code, you have the following check: static int ptrace_attach(struct task_struct *task, long request, unsigned long addr, unsigned long flags) { ...

Disabling interrupts and masking interrupts

Hello, what is the difference between disabling interrupts and masking interrupts ? Disabling interrupts is done, AFAIK, with irq_disable(). (see below) Can someone gives an example of how to mask interrupts with x86/x86_64 ? irq_disable() in x86 goes to native_irq_disable(), which eventually

Re: Disabling interrupts and masking interrupts

at 7:28 PM, Kevin Wilson wkev...@gmail.com wrote: Hello, what is the difference between disabling interrupts and masking interrupts ? Disabling interrupts is done, AFAIK, with irq_disable(). Disabling interrupts means that you have disabled the source of interrupt. Masking means that you

TLB shootdowns in /proc/interrupts (different results)

Hi, I have two x86_64 machines: On the first there is Fedora 18 (x86_64); on the second there is Ubunutu 12.10 (server, 64 bit). I run cat /proc/interrupts on both machines; in both cases, I run this command after an hour when the machine is up. I get: On the fedora machine cat /proc/interrupts |

Re: Disabling interrupts and masking interrupts

308 PCI-MSI-edge snd_hda_intel Also I remember I saw in a book about Kernel that edge interrupts are more common than level interrupts. rgs Kevin On Thu, Mar 7, 2013 at 6:53 PM, valdis.kletni...@vt.edu wrote: On Thu, 07 Mar 2013 17:17:19 +0200, Kevin Wilson said: Does this mean

pi_waiters in task_struct

Hi, Looking into task_struct (include/linux/scehd.h) , we have: /* PI waiters blocked on a rt_mutex held by this task */ struct plist_head pi_waiters; Any ideas what pi stand for ? I assume it has nothing to do with pi from mathematics... rgs. Kevin

hpet misc device usage

Hi, Does anybody knows about a user space utility or tool which uses the hpet misc device (/dev/hpet)? http://lxr.free-electrons.com/source/drivers/char/hpet.c rgs, Kevin ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org

question about

Hi, Any idea which methods adds the following entries: /sys/devices/system/clocksource/clocksource0 /sys/devices/system/clocksource/clocksource0/available_clocksource ? Best, KevinW ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org

cgroup.procs versus tasks (cgroups)

Hi? Any idea what is the difference cgroup.procs entry and tasks entry of cgroup sysfs? both represent pid lists. I ran: cat /sys/fs/cgroup/cpuset/cgroup.procs and cat /sys/fs/cgroup/cpuset/tasks and entries of cgroup.procs appear in tasks. However there are many more tasks than cgroup.procs:

Re: cgroup.procs versus tasks (cgroups)

, Kevin On Tue, Apr 2, 2013 at 10:40 AM, Vlad Dogaru ddv...@herebedragons.ro wrote: On Tue, Apr 02, 2013 at 05:54:56AM +0300, Kevin Wilson wrote: Hi? Any idea what is the difference cgroup.procs entry and tasks entry of cgroup sysfs? both represent pid lists. I ran: cat /sys/fs/cgroup/cpuset

oops in a kernel module

Hello, I have written a short kernel module which should zero a network SNMP mib. I have OOPs. My idea was to take an existing macro that adds an integer to a network SNMP mib and to change it so that it would zero that counter. So I tool the TCP_ADD_STATS() macro - see in the comments of the

Re: oops in a kernel module

28, 2013 at 7:07 PM, valdis.kletni...@vt.edu wrote: On Sat, 27 Apr 2013 19:34:00 +0300, Kevin Wilson said: Hello, static int __init init_zeromib(void) This is your init routine... { int ret = 0; printk(in %s\n,__func__); Missing KERN_DEBUG or similar here. This can cause it to fail

question about vlan driver

Hello, I have a short question about vlan driver; I see in the vlan driver the following code when creating a new vlan interface: vlan_newlink() { ... if (data[IFLA_VLAN_PROTOCOL]) proto = nla_get_be16(data[IFLA_VLAN_PROTOCOL]); else proto = htons(ETH_P_8021Q); ... } see:

Re: question about vlan driver

://www.spinics.net/lists/netdev/msg233587.html but nothing else It is probably a matter of sync between iproute version and kernel version rgs Kevin On Mon, May 6, 2013 at 9:26 PM, Bjørn Mork bj...@mork.no wrote: Kevin Wilson wkev...@gmail.com writes: Hello, I have a short question about vlan

which kernel config creates /dev/usb ?

Hello, I have configured a kernel, built it and rebooted It is 3.9.0 kernel. There is no /dev/usb after boot (there is of course /dev) Any idea which kernel config creates /dev/usb ? rgs, Kevin ___ Kernelnewbies mailing list

IOCTLs versus netlink

Hi, Can someone please explain why are netlink sockets a better communication method between kernel space and userspace ? I know that with IOCTLs we cannot send asynchronous messages to userspace from kernel, and with netlink we can. Are there more things to it? I once heard something about that

stop build of kernel when there is a compilation error when using make -j

Hello, When I run make for a kernel tree, it stops immediately on the first compilation error. However, when I use make -j 4 and there an error, it does not stop immediately because of the parallel build using several CPU cores Is there a way to cause make -j 4 to stop on the first compilation

Re: stop build of kernel when there is a compilation error when using make -j

Hi, What is expect script ? is it in bash? is there a good link for it ? rgs Kevin On Mon, Sep 9, 2013 at 4:15 AM, valdis.kletni...@vt.edu wrote: On Sun, 08 Sep 2013 13:33:06 +0300, Kevin Wilson said: However, when I use make -j 4 and there an error, it does not stop immediately because

Question about tunnels, IPsec and redirect

Hi, I am looking at this patch: http://lists.openwall.net/netdev/2007/08/24/29 and I cannot understand it. Can somebody please try to explain ? more specifically: Can somebody please give an example of some setup of IPsec tunnel where the ip_rt_send_redirect() method should not be called when the

Re: disable module support in kernel

Hi, What do you mean by changing kernel.spec? are you building it with rpmbuild ? can you describe how you are trying to build it ? KW On Fri, Dec 27, 2013 at 4:22 PM, Andy Johnson johnson...@gmail.com wrote: Laxmi, How exactly do you try to disable it? do you set CONFIG_MODULES to N? which

insmod and capabilty

Hi, Does insmod needs some capability ? Is there a capability which when not set, you cannot run perform insmod of a kernel module ? I don't see such capability in man 7 capabilities. regards, Kevin ___ Kernelnewbies mailing list

echo 1 memory.oom_control bash: echo: write error: Invalid argument

Hello, On Fedora 20, I try the following: 1) create a cgroup called 0 /sys/fs/cgroup/memory/0 run: echo 1 /sys/fs/cgroup/memory/0/memory.oom_control bash: echo: write error: Invalid argument Why am I having this error ? According to the documentation:

Re: Regarding bluez stack in linux kernel

Hi, Vivek, The Linux Kernel Networking book by Rami Rosen, Apress, 2014, has a good, extensive and detailed section about the Kernel Bluetooth Stack in the last chapter. see: http://www.apress.com/9781430261964 Regards, Kevin On Wed, Aug 6, 2014 at 5:47 PM, Vivek Panwar

Makefile for a single source file

Hi, I have a single source file which I wrote, implementing a kernel module: helloworld.c In order to built it, I prepared the following Makefile: obj-m += helloworld.o all: make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules clean: make -C /lib/modules/$(shell uname

Re: Makefile for a single source file

Hi, No. This is a newbie question, and I believe this is the right mailing list to get help. Regards, Kevin On Sat, Sep 13, 2014 at 5:36 PM, Kristofer Hallin kristofer.hal...@gmail.com wrote: Is this part of the Eudyptula Challenge? On 13 Sep 2014 16:35, Kevin Wilson wkev...@gmail.com wrote

BUG: unable to handle kernel NULL pointer dereference at (null)

Hello, I am getting this message when running a patched kernel: BUG: unable to handle kernel NULL pointer dereference at (null) Is there some kernel configuration item which enables getting , instead (null), the proper value (I assume it should be a method name) Regards, Kevin

Re: Network subsystem and suggestions

. A bit outdated, but still part of it is relevant and well written. 2) Linux Kernel Networking - Implementation and Theory By Rami Rosen, 2014 http://www.apress.com/9781430261964 An up-to-date in depth book. Regards, Kevin Wilson On Wed, Oct 29, 2014 at 8:00 PM, valdis.kletni...@vt.edu wrote

build a kernel over a mounted NFS partition

Hi, I have a question regarding building a kernel over a mounted NFS partition. I can arrange such a setup, where an NFS server with 1Gb nic will be connected to a very strong server (but where I do not have enough stoage for putting a kernel + it object files). The question is - does it worth it

viewing pr_debug messages

I am using journalctl -kf or journalctl -k to see kernel log messages. However, messages of pr_debug are not shown by this commands. Is there some way to view pr_debug kernel messages with journalctl -k ? regards, Kevin ___ Kernelnewbies mailing

Re: Userspace agent crash and kernel module

Kevin On Tue, Nov 18, 2014 at 1:19 PM, Kevin Wilson wkev...@gmail.com wrote: Hi, I want to write a kernel module which interacts with a userspace daemon. There are cases when the userspace daemon can terminate by some signals. There are also cases where the userspace daemon can crash (in some

Re: Userspace agent crash and kernel module

Kevin On Tue, Nov 18, 2014 at 1:19 PM, Kevin Wilson wkev...@gmail.com wrote: Hi, I want to write a kernel module which interacts with a userspace daemon. There are cases when the userspace daemon can terminate by some signals. There are also cases where the userspace daemon can crash (in some

question about pr_info (newbie)

Hi, I have the following very simply kernel module. The module_init() method has one call to pr_info(Hello world!\n). However, when I run insmod helloWorld.ko I get TWO messages in the kernel log and not one, as I expected: .. Dec 29 11:24:40 kv kernel: [67479.245642] Hello world! Dec 29

Question about ixgbe and ixgbevf

Hi, I have an x86_64 machine (F21) on which ixgbevf is not loaded. I notices that when running modprobe ixgbevf max_vfs = 10 (or any other number), this triggers loading of ixgbevf driver. I will appreciate if someone can exaplain the implementation details of how does this happen. I could not

opening a BUG in kernel bugzilla (https://bugzilla.kernel.org/)

Hi all, Can we open a BUG in kernel bugzilla (https://bugzilla.kernel.org/) against a kernel image which was found on an image which was built from most recent build of Linus tree (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git) but is not reproducible (yet) against the

bitops for handling 32 bits

Hi all, Is there a kernel API for handling 32 bits ? I see a macro like BIT(nr) http://lxr.free-electrons.com/source/include/linux/bitops.h#L6 #define BIT(nr) (1UL (nr)) and also #define BIT_ULL(nr) (1ULL (nr)) However, these macros are using 64 bit semantics, so

Preceding a method call with (void)

Hi all, I intend to send a patch to the kernel, and my question is about preceding a method with (void). In several OpenSource UserSpace projects, I encountered usage of preceding a method invocation with (void). For example: (void) myFunc(param1); I did not encounter such cases in the kernel

getting warning when a method parameter in a kernel module is not used

Hi, When a method parameter in a kernel module is not used, we do not get any warning (as opposed to a variable which is not used). Is there any compilation flag which enables getting warning in such a case ? Regards, Kevin ___ Kernelnewbies mailing

taskstats in kernel and in userspace

Hi, According to http://lxr.free-electrons.com/source/kernel/taskstats.c there is a netlink interface for taskstats. It is not new, it is at least from kernel 3.7 Is there a netlink based utility which uses it ? Regards, Kevin ___ Kernelnewbies mailing

git tags (RC kernels ) and kernel versions (www.kernel.org)

I want to be able to work with git commands with the Linux kernel versions according to what I see in www.kernel.org, and I encounter a difficulty. The following example demonstrates the difficulty I encounter. I see under: https://www.kernel.org/pub/linux/kernel/v4.x/ 13 sub version of the 4.1

Re: Identifying whether a pci device is x1, x4, x8 or x16

Thanks, Bjorn! This worked for me. Is there a way that "lspci -vvvnn" will return only info about a given bdf (like :02:00.0, which is what ethtool -i eth4 returns in the "bus-info" field. Regards, Kevin On Tue, Jun 14, 2016 at 4:06 PM, Bjørn Mork <bj...@mork.no> w

Re: Identifying whether a pci device is x1, x4, x8 or x16

other (there are PCI Gen 1, and not so common but I think that PCI Gen4 are arriving) ? Regards, Kevin On Wed, Jun 15, 2016 at 12:46 AM, John Chludzinski <john.chludzin...@vivaldi.net> wrote: > Try: lshw > > > On 2016-06-14 08:40, Kevin Wilson wrote: >> >> Hi all, &

swap test for cgroups

Hi, I had tried to perform the following test according to: http://lxr.free-electrons.com/source/Documentation/cgroups/memcg_test.txt#L211 mkdir /sys/fs/cgroup/memory/group1 echo $$ > /sys/fs/cgroup/memory/group1/cgroup.procs echo 40M > /sys/fs/cgroup/memory/group1/memory.limit_in_bytes Run a

/sys/devices/system/node/node0 and /sys/devices/system/node1

Hello, Just wonder: I one server I see /sys/devices/system/node/node0 while on a different server I see /sys/devices/system/node/node1 Is this configurable ? what determines whether a machine has only node 0 or only node 1 or both (or more)? Regards, Kevin

Re: initrd and messages in the kernel log

and all messages after (till next boot) are not from initrd but from /lib/modules and/or /boot/vmlinuz? Thanks, Kevin On Fri, Jan 20, 2017 at 10:50 AM, Greg KH <g...@kroah.com> wrote: > On Fri, Jan 20, 2017 at 10:33:46AM +0200, Kevin Wilson wrote: >> Hello, >> Question

initrd and messages in the kernel log

Hello, Question: in the boot process on my machine (Ubuntu 14), the standard Ubuntu initrd image is used. In that process of bootstrapping from initrd, several kernel modules from the initrd module are used. I believe that some of these modules are printing module messages using the standard

Catching invoking a new process by the audit subsyetm

Hi, Is it possible to catch invoking a new process by the audit subsyetm? Regards, Kevin ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

Sending a patch with git-email and a gmail account

Hi, I tried to send a patch with git-email account following tutorials I found on the web. I got and error saying "Unable to initialize SMTP..." I saw that many others get this error. I tried many solutions, but the only thing that worked was by going the gmail account setting, to "Sign-in &

building af_packet as a kernel module

Hello, I have tried to set CONFIG_PACKET=m in kernel 4.11 and rebuilt the kernel and rebooted. I am using Ubuntu 16.04. After reboot, the af_packet.ko kernel module is loaded: lsmod shows: af_packet 45056 2 But I cannot remove it: rmmod af_packet rmmod: ERROR: Module af_packet is

Re: minimum commit id length when fixing a patch

its ID should show a unique patch (at least for kernel git trees, which is primarily where I use it) Regards, Kevin On Thu, Jun 8, 2017 at 1:46 PM, Bjørn Mork <bj...@mork.no> wrote: > Kevin Wilson <wkev...@gmail.com> writes: > >> Thanks, Bjorn. >> >> I added i

Re: minimum commit id length when fixing a patch

Wed Jun 7 16:26:15 2017 +0300 IB/mlx4: Bump driver version Does it work for you ? Regards, Kevin On Tue, Jun 6, 2017 at 11:57 PM, Bjørn Mork <bj...@mork.no> wrote: > Kevin Wilson <wkev...@gmail.com> writes: > >> Hi, >> I want to send a patch to LKML f

minimum commit id length when fixing a patch

Hi, I want to send a patch to LKML fixing something wrong which was caused by other patch. Form what I understand, it is a good practice to mention the commit title and the commit ID. A commit ID is very long. My question is: when mentioning in my commit log the patch that caused the problem,

Numa node 0 is missing from /sys/devices/system/node , only Numa node 1 is shown

Hi, I have Ubuntu 14.04.5 LTS on x86_64 machine. I am using the kernel as shipped with the distro, no modification whatsoever. After fresh reboot I do see Numa node 1 but there is no Numa node 0 under: /sys/devices/system/node What can be the reason for this ? lscpu shows two sockets but only

specifying in the kernel command line

Hello, I have an x86_64 host with 4GB of Physical RAM running Fedora 25. I have a question about hugepages allocation on this host. In: https://www.kernel.org/doc/Documentation/vm/hugetlbpage.txt I see that you can use "hugepages=N" kernel parameter (in grub) for specifying the number of