December 2017 - kernelnewbies@kernelnewbies.org

where is __percpu_seg initialized?
by 落痕 March 28, 2018

March 28, 2018

Hi all: I knew the kernel implement the per-cpu variable via __percpu_seg. For example on x86 architecture, it's defined as: #ifdef CONFIG_X86_64 #define __percpu_seg gs #define __percpu_mov_op movq #else #define __percpu_seg fs #define __percpu_mov_op movl #endif But I'm curious where __percpu_seg is initialized?? I fail to find the relative code. Thanks.

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Mailing list
by Farouk Maâboudallah Dec. 31, 2017

Dec. 31, 2017

Hi ! My email is farouk.maaboudallah(a)gmail.com Best regards Sent from my iPhone

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Re: building debug version of klibc
by Anatoly Pugachev Dec. 30, 2017

Dec. 30, 2017

On Sat, Dec 30, 2017 at 2:30 PM, Sam Ravnborg <sam(a)ravnborg.org> wrote: > Hi Anatoly > > On Sat, Dec 30, 2017 at 01:54:05PM +0300, Anatoly Pugachev wrote: >> Hello! >> >> Can someone please help me in building debug version of klibc ? >> >> I've cloned git://git.kernel.org/pub/scm/libs/klibc/klibc.git , but >> failed to build it with debug info >> >> added "-g" to HOSTCFLAGS in Makefile, but > > HOSTCFLAGS is used when building tools running on your build machine. > > Try something like this (untested, whitespace damaged): > > diff --git a/scripts/Kbuild.klibc b/scripts/Kbuild.klibc > index f500d535..3e8124f7 100644 > --- a/scripts/Kbuild.klibc > +++ b/scripts/Kbuild.klibc > @@ -69,7 +69,7 @@ include $(srctree)/scripts/Kbuild.include > KLIBCREQFLAGS := $(call cc-option, -fno-stack-protector, ) \ > $(call cc-option, -fwrapv, ) > KLIBCARCHREQFLAGS := > -KLIBCOPTFLAGS := > +KLIBCOPTFLAGS := -g > KLIBCWARNFLAGS := -W -Wall -Wno-sign-compare -Wno-unused-parameter > KLIBCSHAREDFLAGS := > KLIBCBITSIZE := > > If you use make V=1 then you should be able to see the > full gcc command line, where -g should be included with > theabove fix. Sam, thanks! I did notice that later as well, but I've changed KLIBCCFLAGS to include "-g" and changed strip to echo: mator@ttip:~/klibc$ git diff diff --git a/scripts/Kbuild.klibc b/scripts/Kbuild.klibc index f500d535..40cbfd60 100644 --- a/scripts/Kbuild.klibc +++ b/scripts/Kbuild.klibc @@ -74,7 +74,7 @@ KLIBCWARNFLAGS := -W -Wall -Wno-sign-compare -Wno-unused-parameter KLIBCSHAREDFLAGS := KLIBCBITSIZE := KLIBCLDFLAGS := -KLIBCCFLAGS := +KLIBCCFLAGS := -g # Defaults for arch to override KLIBCARCHINCFLAGS = -I$(KLIBCKERNELOBJ)/arch/$(KLIBCARCH)/include @@ -99,7 +99,7 @@ KLIBCAR := $(AR) klibc-ar = $(KLIBCAR) $(if $(KBUILD_REPRODUCIBLE),$(2),$(1)) KLIBCRANLIB := $(call klibc-ar,s,Ds) -KLIBCSTRIP := $(STRIP) +KLIBCSTRIP := echo KLIBCNM := $(NM) KLIBCOBJCOPY := $(OBJCOPY) KLIBCOBJDUMP := $(OBJDUMP) @@ -126,7 +126,7 @@ KLIBCCPPFLAGS += $(KLIBCDEFS) KLIBCCFLAGS += $(KLIBCCPPFLAGS) $(KLIBCREQFLAGS) $(KLIBCARCHREQFLAGS) \ $(KLIBCOPTFLAGS) $(KLIBCWARNFLAGS) KLIBCAFLAGS += -D__ASSEMBLY__ $(KLIBCCFLAGS) -KLIBCSTRIPFLAGS += --strip-all -R .comment -R .note +#KLIBCSTRIPFLAGS += --strip-all -R .comment -R .note KLIBCLIBGCC_DEF := $(shell $(KLIBCCC) $(KLIBCCFLAGS) --print-libgcc) KLIBCLIBGCC ?= $(KLIBCLIBGCC_DEF) mator@ttip:~/klibc$ this helped me to produce exec with debug info and stack trace: (gdb) file ./usr/kinit/fstype/static/fstype Reading symbols from ./usr/kinit/fstype/static/fstype...done. (gdb) run Starting program: /home/mator/klibc/usr/kinit/fstype/static/fstype Program received signal SIGSEGV, Segmentation fault. __syscall_common () at usr/klibc/arch/sparc64/syscall.S:15 15 st %o0,[%g4] (gdb) bt #0 __syscall_common () at usr/klibc/arch/sparc64/syscall.S:15 #1 0x00000000001010d4 in identify_fs () #2 0x00000000001001f0 in main () PS: added sparclinux@vger , first thread message is http://www.zytor.com/pipermail/klibc/2017-December/003962.html

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building debug version of klibc
by Anatoly Pugachev Dec. 30, 2017

Dec. 30, 2017

Hello! Can someone please help me in building debug version of klibc ? I've cloned git://git.kernel.org/pub/scm/libs/klibc/klibc.git , but failed to build it with debug info added "-g" to HOSTCFLAGS in Makefile, but $ make -j KLIBCKERNELSRC=`pwd`/../linux-2.6/usr still strips every debug symbol , and i'm failed to change scripts/Kbuild.klibc and Makefile to remove strip usage klibc$ find . -name fstype | xargs file ./usr/kinit/fstype: directory ./usr/kinit/fstype/static/fstype: ELF 64-bit MSB executable, SPARC V9, relaxed memory ordering, version 1 (SYSV), statically linked, stripped ./usr/kinit/fstype/shared/fstype: ELF 64-bit MSB executable, SPARC V9, relaxed memory ordering, version 1 (SYSV), statically linked, interpreter /lib/klibc-M67ne2AU3wnuYln_9h2L1vfH5J0.so, stripped I started to get segfault in fstype: linux-2.6$ make install ... DEPMOD 4.15.0-rc5-00149-g5aa90a845892 sh ./arch/sparc/boot/install.sh 4.15.0-rc5-00149-g5aa90a845892 arch/sparc/boot/zImage \ System.map "/boot" run-parts: executing /etc/kernel/postinst.d/apt-auto-removal 4.15.0-rc5-00149-g5aa90a845892 /boot/vmlinuz-4.15.0-rc5-00149-g5aa90a845892 run-parts: executing /etc/kernel/postinst.d/initramfs-tools 4.15.0-rc5-00149-g5aa90a845892 /boot/vmlinuz-4.15.0-rc5-00149-g5aa90a845892 update-initramfs: Generating /boot/initrd.img-4.15.0-rc5-00149-g5aa90a845892 Segmentation fault run-parts: executing /etc/kernel/postinst.d/zz-update-grub 4.15.0-rc5-00149-g5aa90a845892 /boot/vmlinuz-4.15.0-rc5-00149-g5aa90a845892 Dec 30 12:51:06 ttip kernel: fstype[162686]: segfault at 38 ip 000000008001069c (rpc 0000000080004820) sp 000007feffdf53a1 error 1 in klibc-g_9mplOvk_73CeIA8YN-t9vhxyc.so[80000000+14000] linux-2.6$ gdb -q -c core.164896 [New LWP 164896] Core was generated by `/usr/lib/klibc/bin/fstype /dev/vdiska2'. Program terminated with signal SIGSEGV, Segmentation fault. #0 0x000000008001069c in ?? () linux-2.6$ $ find /usr -name fstype | xargs file /usr/lib/klibc/bin/fstype: ELF 64-bit MSB executable, SPARC V9, relaxed memory ordering, version 1 (SYSV), statically linked, interpreter /lib/klibc-g_9mplOvk_73CeIA8YN-t9vhxyc.so, stripped linux-2.6# file -s /dev/vdiska2 /dev/vdiska2: Linux rev 1.0 ext4 filesystem data, UUID=f2eda779-5310-4af2-b48a-b43db51c0961 (needs journal recovery) (extents) (64bit) (large files) (huge files) $ dpkg -S /usr/lib/klibc/bin/fstype klibc-utils: /usr/lib/klibc/bin/fstype $ dpkg -l klibc-utils ||/ Name Version Architecture Description +++-==================================-======================-======================-========================================================================= ii klibc-utils 2.0.4-10 sparc64 small utilities built with klibc for early boot $ apt show klibc-utils Package: klibc-utils Version: 2.0.4-10 Priority: optional Section: libs Source: klibc Maintainer: maximilian attems <maks(a)debian.org> Installed-Size: 522 kB Depends: libklibc (= 2.0.4-10) Breaks: initramfs-tools (<< 0.123~) Homepage: https://git.kernel.org/cgit/libs/klibc/klibc.git Download-Size: 107 kB APT-Manual-Installed: no APT-Sources: http://ftp.ports.debian.org/debian-ports unstable/main sparc64 Packages Description: small utilities built with klibc for early boot This package contains a collection of programs that are linked against klibc. These duplicate some of the functionality of a regular Linux toolset, but are typically much smaller than their full-function counterparts. They are intended for inclusion in initramfs images and embedded systems.

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ReviewRequest of a booklet on System Concepts
by Rishi Agrawal Dec. 26, 2017

Dec. 26, 2017

Hi All, I have written this booklet http://sys.readthedocs.io/en/latest/ explaining some concepts related to "glibc and system calls ". This will be useful for the newbies who are learning Linux System Programming. I request the members of the group to kindly review it once and let me know if anything is incorrect or can be written and explained in a better way. If someone wants to add more contents he/she can surely do by raising a "pull request" in the github repo. My apologies if this is not the right group for it as I do not know of any other group with this level of expertise. -- Regards, Rishi Agrawal A simple act of caring creates an endless ripple. Be the change that you wish to see in the world. Be thoroughly used up when you die, for the harder you work, the more you live.

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Unable to compile linux-kernel pulled from nf-next tree
by Harsha Sharma Dec. 19, 2017

Dec. 19, 2017

Hello, I'm working on a task in netfilter and trying to compile linux-kernel pulled from nf-next tree. https://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next.git but fail with these errors. make-- Kernel: arch/x86/boot/bzImage is ready (#4) MODPOST 4905 modules fs/ufs/ufs.o: Invalid argument scripts/Makefile.modpost:92: recipe for target '__modpost' failed make[1]: *** [__modpost] Error 1 Makefile:1211: recipe for target 'modules' failed make: *** [modules] Error 2 sudo make modules_install install-- cp: cannot stat 'net/nsh/nsh.ko': No such file or directory At main.c:291: - SSL error:02001002:system library:fopen:No such file or directory: bss_file.c:175 - SSL error:2006D080:BIO routines:BIO_new_file:no such file: bss_file.c:178 sign-file: /lib/modules/4.14.0-rc8+/kernel/net/nsh/nsh.ko: No such file or directory scripts/Makefile.modinst:36: recipe for target 'net/nsh/nsh.ko' failed make[2]: *** [net/nsh/nsh.ko] Error 1 Makefile:1232: recipe for target '_modinst_' failed make[1]: *** [_modinst_] Error 2 Makefile:527: recipe for target '__build_one_by_one' failed make: *** [__build_one_by_one] Error 2 Any help will be appreciated. Thanks. Regards, Harsha Sharma

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Device driver over network
by Max Ruttenberg Dec. 19, 2017

Dec. 19, 2017

Hi all, I have two compute nodes on a machine that are both running embedded Linux. The nodes are connected to each other over Ethernet. The both have an i2c bus. Node A has a thermal sensor. Node B has three fans. Right now I have a user space application running on node B that uses ssh to read from node A's thermal sensor and then adjust the fan speeds accordingly. I am wondering if there's away instead to have a hwmon driver running on Node B for the thermal monitor running on node A. This way I could get rid of the user space application and replace it with something a little bit more standard like thermald. Is this something that people have done? Maybe if not this specifically, how about a driver for a device over the network? -- Max Ruttenberg, Member of the Technical Staff Emu Technology 270 W 39th St. #1302 New York, NY 10018

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Facing problem with mutt for replying or sending mails to linux kernel mailing list
by Pravin Shedage Dec. 18, 2017

Dec. 18, 2017

Hi Everyone, Sending mail from mutt failed Error: *SMTP session failed: 501 5.5.4 https://support.google.com/mail/?p=helo <https://support.google.com/mail/?p=helo> a67sm14180316pgc.5 - gsmtp* I follow the instructions from https://kernelnewbies.org/FirstKernelPatch http://elixir.free-electrons.com/linux/latest/source/Documentation/process/… to setup environments and send patch to linux kernel for review. Mutt able to fetch mail from my gmail mail box but sending mail fails with following error: *SSL/TLS connection using TLS1.2 (ECDHE-RSA/AES-128-GCM/AEAD)-- Mutt: Compose [Approx. msg size: 0.1K Atts: 1]-------------------------------------------------------------------------------------------SMTP session failed: 501 5.5.4 https://support.google.com/mail/?p=helo <https://support.google.com/mail/?p=helo> a67sm14180316pgc.5 - gsmtp* krishna@krishna-pc:~$ *tail -f /var/log/mail.log* Dec 9 01:01:03 krishna-pc sm-msp-queue[15372]: unable to qualify my own domain name (krishna-pc) -- using short name Dec 9 01:20:01 krishna-pc sm-msp-queue[16297]: My unqualified host name (krishna-pc) unknown; sleeping for retry Dec 9 09:32:48 krishna-pc sm-mta[2043]: starting daemon (8.15.2): SMTP+queueing@00:10:00 Dec 9 09:32:49 krishna-pc sm-msp-queue[1325]: unable to qualify my own domain name (krishna-pc) -- using short name Dec 9 09:40:01 krishna-pc sm-msp-queue[3338]: My unqualified host name (krishna-pc) unknown; sleeping for retry krishna@krishna-pc:~$ *Following are my configuration which is setup on * krishna@krishna-pc:~$ *lsb_release -a* No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 16.04.3 LTS Release: 16.04 Codename: xenial krishna@krishna-pc:~$ *uname -a* Linux krishna-pc 4.10.0-42-generic #46~16.04.1-Ubuntu SMP Mon Dec 4 15:57:59 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux krishna@krishna-pc:~$ krishna@krishna-pc:~$ *cat ~/.muttrc* set sendmail="/usr/bin/esmtp" set realname = "Pravin Shedge" set from = "pravin.shedge4linux(a)gmail.com" set use_from = yes set envelope_from = yes set edit_headers = yes set smtp_url = 'smtps://pravin.shedge4linux@gmail.com@smtp.gmail.com' set smtp_pass = '****' set imap_user = 'pravin.shedge4linux(a)gmail.com' set imap_pass = '****' set folder = 'imaps://imap.gmail.com/' set spoolfile = +INBOX set ssl_force_tls = yes #set ssl_starttls = yes # ## G to get mail #bind index G imap-fetch-mail set editor = "vi" set edit_headers = yes # See the headers when editing set charset = UTF-8 # value of $LANG; also fallback for send_charset set send_charset="us-ascii:utf-8" set record="" set postponed="+[Gmail]/Drafts" set mbox="imaps://imap.gmail.com/[Gmail]/All Mail" set trash="imaps://imap.gmail.com/[Gmail]/Trash" # Sender, email address, and sign-off line must match # unset use_domain # because joe@localhost is just embarrassing #set include=ask-yes #set print=ask-yes #set postpone=ask-yes #set postponed = "imaps://imap.gmail.com/[Gmail]/Drafts" #set header_cache = "~/.mutt/cache/headers" #set message_cachedir = "~/.mutt/cache/bodies" #set certificate_file = "~/.mutt/certificates" #set move = no #set imap_keepalive = 900 #set imap_passive krishna@krishna-pc:~$ krishna@krishna-pc:~$* cat .gitconfig* [user] email = pravin.shedge4linux(a)gmail.com name = Pravin Shedge [sendemail] smtpencryption = tls smtpserver = smtp.gmail.com smtpuser = pravin.shedge4linux(a)gmail.com smtpserverport = 587 smtppass = "****" krishna@krishna-pc:~$* cat ~/.esmtprc* identity "pravin.shedge4linux(a)gmail.com" hostname smtp.gmail.com:587 username "pravin.shedge4linux(a)gmail.com" password "****" starttls required krishna@krishna-pc:~$ *tail -f /var/log/syslog* Dec 9 10:40:01 krishna-pc CRON[4755]: (smmsp) CMD (test -x /etc/init.d/sendmail && test -x /usr/share/sendmail/sendmail && test -x /usr/lib/sm.bin/sendmail && /usr/share/sendmail/sendmail cron-msp) Dec 9 10:44:30 krishna-pc systemd-timesyncd[609]: Timed out waiting for reply from [2001:67c:1560:8003::c7]:123 (ntp.ubuntu.com) Dec 9 10:45:01 krishna-pc CRON[4831]: (root) CMD (command -v debian-sa1 > /dev/null && debian-sa1 1 1) krishna@krishna-pc:~$ krishna@krishna-pc:~$* cat /etc/resolv.conf* # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8) # DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN nameserver 127.0.1.1 search photonmax3g.wifi krishna@krishna-pc:~$ krishna@krishna-pc:~$* ip addr* 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: enp2s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN group default qlen 1000 link/ether 00:26:2d:74:82:d3 brd ff:ff:ff:ff:ff:ff 3: wlp4s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000 link/ether 90:4c:e5:56:c5:a0 brd ff:ff:ff:ff:ff:ff 5: enx001e101f0000: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 00:1e:10:1f:00:00 brd ff:ff:ff:ff:ff:ff inet 192.168.1.100/24 brd 192.168.1.255 scope global dynamic enx001e101f0000 valid_lft 86387sec preferred_lft 86387sec inet6 fe80::8fff:8915:878b:1b6b/64 scope link valid_lft forever preferred_lft forever krishna@krishna-pc:~$ cat /etc/resolv.conf # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8) # DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN nameserver 127.0.1.1 search photonmax3g.wifi krishna@krishna-pc:~$* cat /etc/hosts* 127.0.0.1 localhost 127.0.0.1 krishna-pc # The following lines are desirable for IPv6 capable hosts ::1 ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters krishna@krishna-pc:~$ Do I missing something ? Please let me know.... Thanks & Regards PraviN +919156991946

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submitting a patch for a stable tree
by Martin Kaiser Dec. 18, 2017

Dec. 18, 2017

Dear all, I tried to submit a patch for 4.14 that was already accepted upstream and is in linux-next and the 4.15-rcs. To understand how this should be done, I looked at https://www.kernel.org/doc/html/v4.14/process/stable-kernel-rules.html and tried to follow Option 2. It looks like I didn't get it right. I started with a tree that contains the patch and ran git format-patch -1 <commit id> and then git send-email --to stable(a)verg.kernel.org \ --cc <the original maintainer and reviewers> \ --annotate <patch file> I added the upstream commit id above the original commit message and a tag line Cc: <stable(a)vger.kernel.org> # 4.14.x to the patch and sent it out. Is there anything that's wrong or missing? Is there a mailing list archive for stable(a)vger.kernel.org where I can have a look at correct submissions and check that my submission made it to the list? Thanks for your help, Martin

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why this field is taskstats. ac_sched is specifically aligned as 8?
by Shiyao MA Dec. 15, 2017

Dec. 15, 2017

Hi, http://elixir.free-electrons.com/linux/latest/source/include/uapi/linux/tas… Why the field is taskstats. ac_sched aligned as 8 ? -- Best, Shiyao

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