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running queue processes
by Mustafa Hussain May 4, 2015

May 4, 2015

Is there a way to show processes in running queue only form terminal?

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Module compilation error on another machine
by Harsh Jain May 4, 2015

May 4, 2015

Hi All, I am trying to compile simple kernel module. It gives following error. Same module compiles succesfully on another 64 bit ubuntu OS.Any idea what different in environment can cause this. Both machine are ubuntu 12.04. On 32 ubuntu bit compilation fails. In file included from /home/aricent/try5/eudy_misc_driver.c:7:0: include/asm-generic/uaccess.h:41:0: warning: "access_ok" redefined [enabled by default] #define access_ok(type, addr, size) __access_ok((unsigned long)(addr),(size)) ^ In file included from /usr/src/linux-headers-3.13.0-43-generic/arch/x86/include/asm/sections.h:5:0, from /usr/src/linux-headers-3.13.0-43-generic/arch/x86/include/asm/hw_irq.h:26, from include/linux/irq.h:368, from /usr/src/linux-headers-3.13.0-43-generic/arch/x86/include/asm/hardirq.h:5, from include/linux/preempt_mask.h:5, from include/linux/sched.h:25, from include/asm-generic/uaccess.h:9, from /home/aricent/try5/eudy_misc_driver.c:7: /usr/src/linux-headers-3.13.0-43-generic/arch/x86/include/asm/uaccess.h:80:0: note: this is the location of the previous definition #define access_ok(type, addr, size) \ In file included from /home/aricent/try5/eudy_misc_driver.c:7:0: include/asm-generic/uaccess.h:337:1: error: static declaration of ‘clear_user’ follows non-static declaration clear_user(void __user *to, unsigned long n) ^ In file included from /usr/src/linux-headers-3.13.0-43-generic/arch/x86/include/asm/sections.h:5:0, from /usr/src/linux-headers-3.13.0-43-generic/arch/x86/include/asm/hw_irq.h:26, from include/linux/irq.h:368, from /usr/src/linux-headers-3.13.0-43-generic/arch/x86/include/asm/hardirq.h:5, from include/linux/preempt_mask.h:5, from include/linux/sched.h:25, from include/asm-generic/uaccess.h:9, from /home/aricent/try5/eudy_misc_driver.c:7: /usr/src/linux-headers-3.13.0-43-generic/arch/x86/include/asm/uaccess.h:525:28: note: previous declaration of ‘clear_user’ was here unsigned long __must_check clear_user(void __user *mem, unsigned long len); Regards Harsh Jain

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Eudyptula Mail Format Issue
by me storage May 4, 2015

May 4, 2015

Hi All, I has been participating in this challenge from 8 months. I submitted 5 tasks. Today i submitted my task06 results third time , but intently it's giving reply that "the format is *base64,* So please change and resend it again" So can any please tell me what happened ? because i followed the same approach as previous tasks. Thanks.

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Imx6Q IPU-1/IPU2 Memory Map clarification
by sanjeev sharma May 1, 2015

May 1, 2015

Hello All, I am working on 3.14 kernel for Nitrogen6x Board and during dealing with IPU, I have realized that as per Table 2-1 (System memory map) of the i.MX6 (Q) Reference Manual(Rev2,06/2014) IPU-1 base address is 0x0260_0000 but device Tree Node defined in imx6qdl.dtsi for IPU-1 i.e alias of IPU0 is at @02400000 and for IPU-2 base address is defined at 0x02A0_0000 as per Table 2-1 (System memory map) of the i.MX6 (Q) Reference Manual but device Tree Node defined in imx6q.dtsi for IPU-2 i.e alias of IPU1 is at @02800000. Why Device Tree node for the IPU starting before actual memory map address. Is anyone know the reason behind it ? Thanks in Advance ! Sanjeev Sharma

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Re:execve error
by Avinash Sridharan April 30, 2015

April 30, 2015

Are you passing the arguments to execve correctly? Usually the EFAULT error occurs, cause the argument format to execve is not correct and the kernel is unable to interpret the executable that needs to be launched, or the parameters that need to be passed to the new process. Just an example: http://www.linuxquestions.org/questions/programming-9/execve-alwayse-produc… On Thu, Apr 23, 2015 at 9:00 AM <kernelnewbies-request(a)kernelnewbies.org> wrote: > Send Kernelnewbies mailing list submissions to > kernelnewbies(a)kernelnewbies.org > > To subscribe or unsubscribe via the World Wide Web, visit > http://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. How can I fetch the files likely directory > /usr/src/kernels/<kernel version> from kernel source tree? > (tianlilai) > 2. execve error (Rohith) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 23 Apr 2015 17:59:56 +0800 > From: tianlilai <laitianli2015(a)outlook.com> > Subject: How can I fetch the files likely directory > /usr/src/kernels/<kernel version> from kernel source tree? > To: kernelnewbies(a)kernelnewbies.org > Message-ID: <BLU436-SMTP88F0913B3897AE70E7C950A9ED0(a)phx.gbl> > Content-Type: text/plain; charset="utf-8"; format=flowed > > > Hi,I have built the kernel source tree and running in PC mechine.Now I > want to fetch the files likely directory /usr/src/kernels/<kernel > version> from this kernel source tree.How can I do? Thanks very much! > > > > > ------------------------------ > > Message: 2 > Date: Thu, 23 Apr 2015 17:55:22 +0530 > From: Rohith <itsnotrohit(a)gmail.com> > Subject: execve error > To: kernelnewbies(a)kernelnewbies.org > Message-ID: > < > CABsTBT6S0vRNFo0bxxBcWDx3k8JMpzbYyKbbUB8oxT-W%2B8Tr-A(a)mail.gmail.com> > Content-Type: text/plain; charset="utf-8" > > Hi all, > > I'm facing a strange issue with execve. It fails with -EFAULT > intermittently. I found that whenever it failed the stack allocated to the > process is in the last page of the CONFIG_TASK_SIZE. > > For example, if CONFIG_TASK_SIZE is set to 0x4000_0000, the process would > fail in execve if the stack happens to be in the page: > > 3ffdf000-40000000 rw-p 00000000 00:00 0 [stack] > > I tried changing CONFIG_TASK_SIZE=0x30000000 and the process this time > fails at the end 0x30000000 address. > > I also found that the execve seem to use the largest stack address > (STACK_TOP_MAX, function __bprm_mm_init(), fs/exec.c) while copying > argv/envp to the new process space. > > I don't know how to debug further. I feel that the user process stack > should never be allocated at the CONFIG_TASK_SIZE? Any idea or suggestion > on how to debug further, please tell me. > > thanks, > rohit >

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[PATCH] .gitignore: Simplify Git ignoring generated directories.
by Robert P. J. Day April 29, 2015

April 29, 2015

Signed-off-by: Robert P. J. Day <rpjday(a)crashcourse.ca> --- am i correct in assuming that this change, first of all, makes it clear that only directories are involved and, also, that one can simply ignore all directories with the name "generated"? diff --git a/.gitignore b/.gitignore index 4ad4a98..9301b0c 100644 --- a/.gitignore +++ b/.gitignore @@ -68,9 +68,8 @@ Module.symvers # # Generated include files # -include/config -include/generated -arch/*/include/generated +include/config/ +generated/ # stgit generated dirs patches-* rday -- ======================================================================== Robert P. J. Day Ottawa, Ontario, CANADA http://crashcourse.ca Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday ========================================================================

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4.1-rc1 fails with O3 optimization
by Andev April 28, 2015

April 28, 2015

Hello Newbies, I usually compile my kernel with an unsupported O3 option(why not? :). Today after running the latest 4.1-rc1 kernel with O3, I got a boot failure. This is the first time this has happened for me. If someone is interested in debugging this, please read on. Can you try to reproduce this bug? If yes, can you also bisect this? I am a bit swamped right now and can try to reproduce this only on Wednesday. If you are interested, apply the following patch, compile and see if the kernel boots. Thanks! diff --git a/Makefile b/Makefile index 14c722f..05950ca 100644 --- a/Makefile +++ b/Makefile @@ -297,8 +297,8 @@ CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; \ HOSTCC = gcc HOSTCXX = g++ -HOSTCFLAGS = -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 -fomit-frame-pointer -std=gnu89 -HOSTCXXFLAGS = -O2 +HOSTCFLAGS = -Wall -Wmissing-prototypes -Wstrict-prototypes -O3 -fomit-frame-pointer -std=gnu89 +HOSTCXXFLAGS = -O3 ifeq ($(shell $(HOSTCC) -v 2>&1 | grep -c "clang version"), 1) HOSTCFLAGS += -Wno-unused-value -Wno-unused-parameter \ @@ -616,7 +616,7 @@ KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,) ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE KBUILD_CFLAGS += -Os $(call cc-disable-warning,maybe-uninitialized,) else -KBUILD_CFLAGS += -O2 +KBUILD_CFLAGS += -O3 endif -- Andev

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Re: 4.1-rc1 fails with O3 optimization
by leo kirotawa April 28, 2015

April 28, 2015

that .config you sent is for 4.0-rc2, is that right? here is the diff after a make oldconfig [1] [1] http://pastebin.com/4Lfs2it0 On Tue, Apr 28, 2015 at 12:35 PM, Andev <debiandev(a)gmail.com> wrote: > On Tue, Apr 28, 2015 at 9:03 AM, leo kirotawa <kirotawa(a)gmail.com> wrote: >> I could boot it using qemu. So what's the point? > > Could you try the attached config and see if it boots? > >> >> On Tue, Apr 28, 2015 at 2:41 AM, Andev <debiandev(a)gmail.com> wrote: >>> >>> On Mon, Apr 27, 2015 at 9:00 PM, Bobby Powers <bobbypowers(a)gmail.com> >>> wrote: >>> > Hello, >>> > >>> > Andev wrote: >>> >> I usually compile my kernel with an unsupported O3 option(why not? :). >>> > >>> > Because there have been publications that show on major benchmarks, >>> > the effects of -O3 are indistinguishable from noise: >>> > http://people.cs.umass.edu/~emery/pubs/Stabilizer-UMass-CS-TR2011-43.pdf >>> > >>> > Have you noticed that -O3 provides any performance benefits over -O2? >>> > >>> >>> Look here: http://www.spinics.net/lists/kernel/msg1962561.html >>> >>> Btw, this will help uncover problems in either gcc or the kernel for >>> sure. So no harm in trying! >>> >>> -- >>> Andev >>> >>> _______________________________________________ >>> Kernelnewbies mailing list >>> Kernelnewbies(a)kernelnewbies.org >>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies >> >> >> >> >> -- >> >> ---------------------------------------------- >> Leônidas S. Barbosa (Kirotawa) >> blog: corecode.wordpress.com > > > > -- > Andev -- ---------------------------------------------- Leônidas S. Barbosa (Kirotawa) blog: corecode.wordpress.com

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Is it all right for Netfilter modules to use control buffers (skb->cb)?
by Alberto Leiva April 28, 2015

April 28, 2015

Hi I was assuming yes, since I've seen at least one module doing this. An example is nf_defrag_ipv6 (ipv6_defrag() calls nf_ct_frag6_gather() which calls NFCT_FRAG6_CB()). What confuses me is that the IPv6 subsystem seems to have its own control buffer: - ipv6_rcv() calls IP6CB(): http://lxr.free-electrons.com/source/net/ipv6/ip6_input.c?v=3.17#L102 - then it calls the netfilter chain, which might include nf_defrag_ipv6: http://lxr.free-electrons.com/source/net/ipv6/ip6_input.c?v=3.17#L186 - then ip6_rcv_finish() comes into play, which calls dst_input(), which might well call ip6_input(), which calls ip6_input_finish(). - ip6_input_finish() once again dereferences the IPv6 version of the control buffer: http://lxr.free-electrons.com/source/net/ipv6/ip6_input.c?v=3.17#L219 If Netfilter modules are allowed to wash out control buffers, how does the IPv6 private data seems to be surviving the Netfilter chain? Thanks

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Trying to write/read value at PCI BAR address from Kernel Space
by Robert Clove April 28, 2015

April 28, 2015

Hi, I am trying to write and read PCI BAR address but not getting the expected output. I am using the ioremap api to get the address. Any leads will be fruit full. Regards

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