May 2017 - kernelnewbies@kernelnewbies.org - Kernelnewbies Mailing Lists

devm_ioremap() in a sysfs show method
by Martin Kaiser May 9, 2017

May 9, 2017

Dear all, I'm trying to create a simple sysfs node that prints the content of a register. The code looks like this static ssize_t my_read_reg(struct device *pdev, struct device_attribute *attr, char *buf) { u32 __iomem *reg; reg = devm_ioremap(pdev, 0x581018C4, 4); return scnprintf(buf, PAGE_SIZE, "0x%02x\n", ioread8(reg)); } Is it ok to use devm_ioremap() on the device that I get here? If so, may I assume that devm_ioremap() re-uses an existing mapping and it's ok to call it for each sysfs access? The physical address that I pass to devm_ioremap() is not page-aligned. This seems to work on arm. Is there a recommended (i.e. more portable) way of doing this? Should I map a larger area and use PAGE_ALIGN()? Thanks for your feedback, Martin

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system tap unable to refer a structure definition
by Gadre Nayan May 7, 2017

May 7, 2017

Hi, I am trying a script to read some headers which are passed from one module to another. c = @cast($frags[0]->f_addr, "volioship_hdr_t", "/root/ngadre/unixvm-cvs/src/common/kernel/vxvm/ioship_cvm.h") printf("Arguments: [Frag[0]->size: %d, Frag[0]->f_addr: %u, Sender: %d, Receiver: %d]\n", $frags[0]->f_size, $frags[0]->f_a ddr, c->iosh_sender, c->iosh_receiver) The header file is locally available on the machine. Error Msg: semantic error: type definition 'volioship_hdr_t' not found in '/root/ngadre/unixvm-cvs/src/common/kernel/vxvm/ioship_cvm.h': operator '@cast' at :46:6 source: c = @cast($frags[0]->f_addr, "volioship_hdr_t", "/root/ngadre/unixvm-cvs/src/common/kernel/vxvm/ioship_cvm.h") How do I make system tap refer to this structure. Thanks

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答复: 1. Kernel version for new drivers (Dushara Jayasinghe)
by Wenwu Xu (许文武) May 3, 2017

May 3, 2017

-----邮件原件----- 发件人: kernelnewbies-bounces(a)kernelnewbies.org [mailto:kernelnewbies-bounces@kernelnewbies.org] 代表 kernelnewbies-request(a)kernelnewbies.org 发送时间: 2017年5月3日 0:00 收件人: kernelnewbies(a)kernelnewbies.org 主题: Kernelnewbies Digest, Vol 78, Issue 2 Send Kernelnewbies mailing list submissions to kernelnewbies(a)kernelnewbies.org To subscribe or unsubscribe via the World Wide Web, visit https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies or, via email, send a message with subject or body 'help' to kernelnewbies-request(a)kernelnewbies.org You can reach the person managing the list at kernelnewbies-owner(a)kernelnewbies.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Kernelnewbies digest..." Today's Topics: 1. Kernel version for new drivers (Dushara Jayasinghe) 2. Re: Kernel version for new drivers (Greg KH) 3. Re: Kernel version for new drivers (Dushara Jayasinghe) 4. Regarding The Eudyptula Challenge (Anil Nair) 5. Re: Regarding The Eudyptula Challenge (valdis.kletnieks(a)vt.edu) 6. Re: Regarding The Eudyptula Challenge (Thomas Bracht Laumann Jespersen) ---------------------------------------------------------------------- Message: 1 Date: Tue, 2 May 2017 09:05:18 +1000 From: Dushara Jayasinghe <dushara(a)successful.com.au> Subject: Kernel version for new drivers To: Kernelnewbies(a)kernelnewbies.org Message-ID: <e1398814-a396-cfa0-42e7-883ea420288f(a)successful.com.au> Content-Type: text/plain; charset=utf-8; format=flowed Hi all, Not sure if this has been covered elsewhere. I'm working on a sama5d2 based device where the kernel supported by the hardware vendor is 4.4. Any drivers we develop and test are based on this version of the kernel. Do the kernel maintainers accept drivers for older (but maintained) versions of the kernel? Is there some general policy regarding this or is it a question that I need to ask the maintainer of the subsystem that the driver belongs to? Thanks. DJ ------------------------------ Message: 2 Date: Mon, 1 May 2017 18:03:25 -0700 From: Greg KH <greg(a)kroah.com> Subject: Re: Kernel version for new drivers To: Dushara Jayasinghe <dushara(a)successful.com.au> Cc: Kernelnewbies(a)kernelnewbies.org Message-ID: <20170502010325.GA6311(a)kroah.com> Content-Type: text/plain; charset=us-ascii On Tue, May 02, 2017 at 09:05:18AM +1000, Dushara Jayasinghe wrote: > Hi all, > > Not sure if this has been covered elsewhere. I'm working on a sama5d2 > based device where the kernel supported by the hardware vendor is 4.4. > Any drivers we develop and test are based on this version of the kernel. > Do the kernel maintainers accept drivers for older (but maintained) > versions of the kernel? Nope, for the simple reason that we can't go back in time and add them to old releases :) > Is there some general policy regarding this or is it a question that I > need to ask the maintainer of the subsystem that the driver belongs > to? Have you read the stable_kernel_rules.txt file in the Documentation directory for what type of patch is allowed in the stable kernel releases? It should answer this question. Also look at the development_process/ "book" in the tree, that should help out. In short, you always have to add new features to the latest development verison of the kernel. hope this helps, greg k-h ------------------------------ Message: 3 Date: Tue, 2 May 2017 14:44:23 +1000 From: Dushara Jayasinghe <dushara(a)successful.com.au> Subject: Re: Kernel version for new drivers To: Greg KH <greg(a)kroah.com> Cc: kernelnewbies(a)kernelnewbies.org Message-ID: <2d8eb17d-7fc6-da7f-071f-8901de65189a(a)successful.com.au> Content-Type: text/plain; charset=UTF-8; format=flowed On 2/05/2017 11:03 AM, Greg KH wrote: > In short, you always have to add new features to the latest > development verison of the kernel. > > hope this helps, > It does. Thanks. ------------------------------ Message: 4 Date: Tue, 2 May 2017 10:20:21 +0530 From: Anil Nair <anilcoll90(a)gmail.com> Subject: Regarding The Eudyptula Challenge To: kernelnewbies <kernelnewbies(a)kernelnewbies.org> Message-ID: <CAHkwNTmW4a8iAJyQZKu1Be4qSx%3DxT7eWCt%2B3v2BSL5iQ6mO5TA(a)mail.gmail.com> Content-Type: text/plain; charset=UTF-8 Hi All, Is the following challenge working, http://eudyptula-challenge.org/. I tried mailing little(a)eudyptula-challenge.org 2 to 3 times but there was no reply. Other than the instructions mentioned in http://eudyptula-challenge.org, is there anything that i am missing? -- -- Regards, Anil Nair ------------------------------ Message: 5 Date: Tue, 02 May 2017 01:40:35 -0400 From: valdis.kletnieks(a)vt.edu Subject: Re: Regarding The Eudyptula Challenge To: Anil Nair <anilcoll90(a)gmail.com> Cc: kernelnewbies <kernelnewbies(a)kernelnewbies.org> Message-ID: <42469.1493703635(a)turing-police.cc.vt.edu> Content-Type: text/plain; charset="us-ascii" On Tue, 02 May 2017 10:20:21 +0530, Anil Nair said: > Other than the instructions mentioned in > http://eudyptula-challenge.org, is there anything that i am missing? You're missing the fact that the challenge has been overwhelmed by entrants, and that it can take as much as a few weeks for them to get around to dealing with your submission. -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 486 bytes Desc: not available Url : http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20170502… ------------------------------ Message: 6 Date: Tue, 2 May 2017 15:59:13 +0200 From: Thomas Bracht Laumann Jespersen <laumann.thomas(a)gmail.com> Subject: Re: Regarding The Eudyptula Challenge To: valdis.kletnieks(a)vt.edu Cc: Anil Nair <anilcoll90(a)gmail.com>, kernelnewbies <kernelnewbies(a)kernelnewbies.org> Message-ID: <CAN%3D42sxC4EfJKe2pAtaUh04ynrwXGMM6YpV9Z%3DjPzCwsDsW%3DvQ(a)mail.gmail.com> Content-Type: text/plain; charset=UTF-8 On 2 May 2017 at 07:40, <valdis.kletnieks(a)vt.edu> wrote: > > On Tue, 02 May 2017 10:20:21 +0530, Anil Nair said: > > Other than the instructions mentioned in > > http://eudyptula-challenge.org, is there anything that i am missing? > > You're missing the fact that the challenge has been overwhelmed by entrants, > and that it can take as much as a few weeks for them to get around to dealing > with your submission. Little also announced some time back that the challenge would be closed for new entrants after 20k entrants (at that point there were 19k), so it might be closed already? But yeah, be patient, sometimes little is busy - but he'll get back to you eventually. > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies(a)kernelnewbies.org > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > ------------------------------ _______________________________________________ Kernelnewbies mailing list Kernelnewbies(a)kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies End of Kernelnewbies Digest, Vol 78, Issue 2 ********************************************

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答复: Kernelnewbies Digest, Vol 78, Issue 2
by Wenwu Xu (许文武) May 3, 2017

May 3, 2017

1. Kernel version for new drivers (Dushara Jayasinghe) -----邮件原件----- 发件人: kernelnewbies-bounces(a)kernelnewbies.org [mailto:kernelnewbies-bounces@kernelnewbies.org] 代表 kernelnewbies-request(a)kernelnewbies.org 发送时间: 2017年5月3日 0:00 收件人: kernelnewbies(a)kernelnewbies.org 主题: Kernelnewbies Digest, Vol 78, Issue 2 Send Kernelnewbies mailing list submissions to kernelnewbies(a)kernelnewbies.org To subscribe or unsubscribe via the World Wide Web, visit https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies or, via email, send a message with subject or body 'help' to kernelnewbies-request(a)kernelnewbies.org You can reach the person managing the list at kernelnewbies-owner(a)kernelnewbies.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Kernelnewbies digest..." Today's Topics: 1. Kernel version for new drivers (Dushara Jayasinghe) 2. Re: Kernel version for new drivers (Greg KH) 3. Re: Kernel version for new drivers (Dushara Jayasinghe) 4. Regarding The Eudyptula Challenge (Anil Nair) 5. Re: Regarding The Eudyptula Challenge (valdis.kletnieks(a)vt.edu) 6. Re: Regarding The Eudyptula Challenge (Thomas Bracht Laumann Jespersen) ---------------------------------------------------------------------- Message: 1 Date: Tue, 2 May 2017 09:05:18 +1000 From: Dushara Jayasinghe <dushara(a)successful.com.au> Subject: Kernel version for new drivers To: Kernelnewbies(a)kernelnewbies.org Message-ID: <e1398814-a396-cfa0-42e7-883ea420288f(a)successful.com.au> Content-Type: text/plain; charset=utf-8; format=flowed Hi all, Not sure if this has been covered elsewhere. I'm working on a sama5d2 based device where the kernel supported by the hardware vendor is 4.4. Any drivers we develop and test are based on this version of the kernel. Do the kernel maintainers accept drivers for older (but maintained) versions of the kernel? Is there some general policy regarding this or is it a question that I need to ask the maintainer of the subsystem that the driver belongs to? Thanks. DJ ------------------------------ Message: 2 Date: Mon, 1 May 2017 18:03:25 -0700 From: Greg KH <greg(a)kroah.com> Subject: Re: Kernel version for new drivers To: Dushara Jayasinghe <dushara(a)successful.com.au> Cc: Kernelnewbies(a)kernelnewbies.org Message-ID: <20170502010325.GA6311(a)kroah.com> Content-Type: text/plain; charset=us-ascii On Tue, May 02, 2017 at 09:05:18AM +1000, Dushara Jayasinghe wrote: > Hi all, > > Not sure if this has been covered elsewhere. I'm working on a sama5d2 > based device where the kernel supported by the hardware vendor is 4.4. > Any drivers we develop and test are based on this version of the kernel. > Do the kernel maintainers accept drivers for older (but maintained) > versions of the kernel? Nope, for the simple reason that we can't go back in time and add them to old releases :) > Is there some general policy regarding this or is it a question that I > need to ask the maintainer of the subsystem that the driver belongs > to? Have you read the stable_kernel_rules.txt file in the Documentation directory for what type of patch is allowed in the stable kernel releases? It should answer this question. Also look at the development_process/ "book" in the tree, that should help out. In short, you always have to add new features to the latest development verison of the kernel. hope this helps, greg k-h ------------------------------ Message: 3 Date: Tue, 2 May 2017 14:44:23 +1000 From: Dushara Jayasinghe <dushara(a)successful.com.au> Subject: Re: Kernel version for new drivers To: Greg KH <greg(a)kroah.com> Cc: kernelnewbies(a)kernelnewbies.org Message-ID: <2d8eb17d-7fc6-da7f-071f-8901de65189a(a)successful.com.au> Content-Type: text/plain; charset=UTF-8; format=flowed On 2/05/2017 11:03 AM, Greg KH wrote: > In short, you always have to add new features to the latest > development verison of the kernel. > > hope this helps, > It does. Thanks. ------------------------------ Message: 4 Date: Tue, 2 May 2017 10:20:21 +0530 From: Anil Nair <anilcoll90(a)gmail.com> Subject: Regarding The Eudyptula Challenge To: kernelnewbies <kernelnewbies(a)kernelnewbies.org> Message-ID: <CAHkwNTmW4a8iAJyQZKu1Be4qSx%3DxT7eWCt%2B3v2BSL5iQ6mO5TA(a)mail.gmail.com> Content-Type: text/plain; charset=UTF-8 Hi All, Is the following challenge working, http://eudyptula-challenge.org/. I tried mailing little(a)eudyptula-challenge.org 2 to 3 times but there was no reply. Other than the instructions mentioned in http://eudyptula-challenge.org, is there anything that i am missing? -- -- Regards, Anil Nair ------------------------------ Message: 5 Date: Tue, 02 May 2017 01:40:35 -0400 From: valdis.kletnieks(a)vt.edu Subject: Re: Regarding The Eudyptula Challenge To: Anil Nair <anilcoll90(a)gmail.com> Cc: kernelnewbies <kernelnewbies(a)kernelnewbies.org> Message-ID: <42469.1493703635(a)turing-police.cc.vt.edu> Content-Type: text/plain; charset="us-ascii" On Tue, 02 May 2017 10:20:21 +0530, Anil Nair said: > Other than the instructions mentioned in > http://eudyptula-challenge.org, is there anything that i am missing? You're missing the fact that the challenge has been overwhelmed by entrants, and that it can take as much as a few weeks for them to get around to dealing with your submission. -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 486 bytes Desc: not available Url : http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20170502… ------------------------------ Message: 6 Date: Tue, 2 May 2017 15:59:13 +0200 From: Thomas Bracht Laumann Jespersen <laumann.thomas(a)gmail.com> Subject: Re: Regarding The Eudyptula Challenge To: valdis.kletnieks(a)vt.edu Cc: Anil Nair <anilcoll90(a)gmail.com>, kernelnewbies <kernelnewbies(a)kernelnewbies.org> Message-ID: <CAN%3D42sxC4EfJKe2pAtaUh04ynrwXGMM6YpV9Z%3DjPzCwsDsW%3DvQ(a)mail.gmail.com> Content-Type: text/plain; charset=UTF-8 On 2 May 2017 at 07:40, <valdis.kletnieks(a)vt.edu> wrote: > > On Tue, 02 May 2017 10:20:21 +0530, Anil Nair said: > > Other than the instructions mentioned in > > http://eudyptula-challenge.org, is there anything that i am missing? > > You're missing the fact that the challenge has been overwhelmed by entrants, > and that it can take as much as a few weeks for them to get around to dealing > with your submission. Little also announced some time back that the challenge would be closed for new entrants after 20k entrants (at that point there were 19k), so it might be closed already? But yeah, be patient, sometimes little is busy - but he'll get back to you eventually. > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies(a)kernelnewbies.org > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > ------------------------------ _______________________________________________ Kernelnewbies mailing list Kernelnewbies(a)kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies End of Kernelnewbies Digest, Vol 78, Issue 2 ********************************************

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Why does the kernel hang with this use of netlink sockets?
by Akshay Narayan May 2, 2017

May 2, 2017

I have written a kernel module and userspace program which use a netlink socket to communicate (full source here: https://github.com/ akshayknarayan/netlink-test). The kernel module periodically multicasts a message, and the userspace program listens on the socket. Relevant source snippets: Kernel module: 43 res = nlmsg_multicast( 44 nl_sk, // @sk: netlink socket to spread messages to 45 skb_out, // @skb: netlink message as socket buffer 46 0, // @portid: own netlink portid to avoid sending to yourself 47 MYMGRP, // @group: multicast group id 48 GFP_KERNEL // @flags: allocation flags 49 ); 50 if (res < 0) { 51 printk(KERN_INFO "Error while sending to user: %d\n", res); 52 } else { 53 mod_timer(&timer, jiffies + msecs_to_jiffies(1)); 54 printk(KERN_INFO "Send ok\n"); 55 } Userspace program: 39 void nl_recv(int sock) { ... 54 ret = recvmsg(sock, &msg, 0); 55 if (ret < 0) 56 printf("ret < 0.\n"); 57 else 58 printf("received message payload: %s\n", (char*) NLMSG_DATA((struct nlmsghdr *) &buffer)); 59 } 60 61 int main(int argc, char *argv[]) { ... 69 while (1) { 70 nl_recv(nls); 71 sleep(1); 72 count++; 73 } If the call to sleep is removed, there is no issue. However, with the call, on kernel 4.10 the kernel hangs after the kernel module is loaded. There's no relevant information in /var/log/syslog after reboot. It seems that some netlink buffer is getting filled, but in this case I would expect nlmsg_multicast to return ENOBUFS. Thanks, Akshay

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Regarding The Eudyptula Challenge
by Anil Nair May 2, 2017

May 2, 2017

Hi All, Is the following challenge working, http://eudyptula-challenge.org/. I tried mailing little(a)eudyptula-challenge.org 2 to 3 times but there was no reply. Other than the instructions mentioned in http://eudyptula-challenge.org, is there anything that i am missing? -- -- Regards, Anil Nair

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Kernel version for new drivers
by Dushara Jayasinghe May 2, 2017

May 2, 2017

Hi all, Not sure if this has been covered elsewhere. I'm working on a sama5d2 based device where the kernel supported by the hardware vendor is 4.4. Any drivers we develop and test are based on this version of the kernel. Do the kernel maintainers accept drivers for older (but maintained) versions of the kernel? Is there some general policy regarding this or is it a question that I need to ask the maintainer of the subsystem that the driver belongs to? Thanks. DJ

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endian patches
by Tobin C. Harding May 1, 2017

May 1, 2017

Should [drivers/staging/*] patches to endian code be tested on hardware before submission? During recent development of ks7010 driver, and from watching patch review on devel(a)linuxdriverproject.org, I formed the opinion that patches fixing endian issues need to be tested on hardware before they can be *guaranteed* to be correct. Is this opinion well founded? thanks, Tobin.

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