Re: How to prevent a module from unloading when in used
On Fri, Jul 18, 2014 at 9:47 AM, Greg KH g...@kroah.com wrote: On Fri, Jul 18, 2014 at 09:43:48AM +0530, Chetan Nanda wrote: On Wed, Jul 16, 2014 at 9:51 PM, Greg KH g...@kroah.com wrote: On Wed, Jul 16, 2014 at 08:57:38PM +0530, Chetan Nanda wrote: On Wed, Jul 16, 2014 at 8:49 PM, Chetan Nanda chetanna...@gmail.com wrote: On Wed, Jul 16, 2014 at 6:39 PM, John de la Garza j...@jjdev.com wrote: On Wed, Jul 16, 2014 at 04:00:18PM +0530, Chetan Nanda wrote: A depends on B, so B is automatically loaded when A is loaded. B module is also directly being used by the user side code via misc interface. . Now when I am unloading module A, via modprobe -r A it is also unloading the module B which is being used by the application and resulting in the kernel crash. You said that A depends on B, right? Why do you have A dependng on B? If it A needs to have B then it makes sense that you can not remove A while B is in use. If A doesn't need B, why not remove the dependency. A is calling few APIs defined by B. But why when user space application is already using module B. (it has already open its device fd) kernel allows to remove it. I tried with doing try_module_get() in the module's open function, it prevent module B unloading but cause thread doing modprobe -r to hang Is there any other way to mark module as busy when being used by user application? Never use try_module_get(), that is racy. What is the user/kernel interface you are using, and why doesn't it automatically increase the module count when userspace opens the interface? It should all be done in a way that your module doesn't need to do anything special. Hi Greg, Thanks for your mail. Module is using misc driver interface to export its functionality to userspace, Need to debug further why module count is not getting incremented automatically when module is open by userspace application via open system call. Are you properly setting the .owner field of your file operations structure to be THIS_MODULE? If not, try fixing that up. If you are, try posting your code for review. greg k-h Hi Greg, Thanks for the hint, indeed that was the issue, .owner field was not set in file operation structure. After setting that, 'modprobe -r A' is hanging. As the module B in use and can't be removed. I am using busybox on embedded Linux, I think this could be a modprobe utility issue. Ideally modprobe should not try to remove the module in used. Thanks, Chetan Nanda ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
hi , question function of net_rx(struct net_device *dev)
hi :
the source code of net_rx(struct net_device *dev) is:
http://lxr.oss.org.cn/source/drivers/net/ethernet/cirrus/cs89x0.c#L670
I can't understand codes about malloc buffer.
##
684 /* Malloc up new buffer. */
685 skb = netdev_alloc_skb(dev, length + 2);
686 if (skb == NULL) {
687 dev-stats.rx_dropped++;
688 return;
689 }
690 skb_reserve(skb, 2);/* longword align L3 header */
##
How to explain 'length + 2' in line of 685? Why add 2 ?
Thank you.
___
Kernelnewbies mailing list
Kernelnewbies@kernelnewbies.org
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: hi , question function of net_rx(struct net_device *dev)
On 7/18/14, lx lxlenovos...@gmail.com wrote:
hi :
the source code of net_rx(struct net_device *dev) is:
http://lxr.oss.org.cn/source/drivers/net/ethernet/cirrus/cs89x0.c#L670
I can't understand codes about malloc buffer.
##
684 /* Malloc up new buffer. */
685 skb = netdev_alloc_skb(dev, length + 2);
686 if (skb == NULL) {
687 dev-stats.rx_dropped++;
688 return;
689 }
690 skb_reserve(skb, 2);/* longword align L3 header */
##
How to explain 'length + 2' in line of 685? Why add 2 ?
That's why it's explained on the line 690.
http://lwn.net/Articles/89597/
Thank you.
___
Kernelnewbies mailing list
Kernelnewbies@kernelnewbies.org
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
--
Regards,
Denis
___
Kernelnewbies mailing list
Kernelnewbies@kernelnewbies.org
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
How to automate checkpatch get_maintainers git send-email of commits range?
Is there script for automated checkpatch.pl get_maintainers.pl git send-email for range of commits? I see none. Would it be welcome to submit such one to kernel tree? -- Andrey Utkin ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Where find Linux Kernel Development Jobs
Hi, What are the best sites, lists, foruns to find Linux Kernel Jobs. No matter the country. Linkedin is still the best place ? Thanks -- Lucas Tanure +55 (19) 988176559 ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
module_param does not work in Ubuntu 13.10 - Kernel 3.10.0-4
Hi Kernelnewbies, Subject : module_param does not work in Ubuntu 13.10 - Kernel 3.10.0-4 For the thread in your mailing list, I would like to suggest the person who posted question that he is not able to pass the parameters to the module in their product. I would like them to check the 'insmod' binary behaviour. If they are using 'busybox'(insmod a softlink to it) for inserting the module with parameters, I would like to suggest them to try with 'insmod' generated out of its source code(compile or available over internet but not the one provided by busybox). I recently faced the same issue, and it turned out to be the issue with the busybox and worked perfectly fine with the insmod I compiled locally. -- Thanks Regards, ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: How to automate checkpatch get_maintainers git send-email of commits range?
On Fri, 2014-07-18 at 15:47 -0700, Joe Perches wrote: On Fri, 2014-07-18 at 18:22 -0400, Theodore Ts'o wrote: and get_maintainers.pl. I think checkpatch Umm, make that get_maintainer... is pretty good about cc'ing mostly the right folk by default. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
