On Mon, 22 Jun 2015 06:29:33 -0700 Clément Bénier <clement.ben...@openwide.fr> said:
Hey! this and the EFL debugging duplicate a generic https://www.enlightenment.org/docs-efl-debug page. lots and lots of overlap here. I've gone over this series of www wiki changes and fixed up some language, typos and made things a bit more consistent (trust me - wiki pages I wrote have typos too and i need to re-read them a few times, so this is no new problem! :)). The extra pages on EFL on various distros is good. but we now have 3 pages about debugging that have a lot of similar content. This needs some fixing. maybe a bunch of smaller pages we include with page>include stuff? we can pick the sub pages to include in master pages for e vs efl vs generic. basic tutorial - great! it needs review though. formatting of code is inconsistent with other examples and so on. the basic tutorials page is also relying on manual spaces to space out the tutorial items and screenshots. ;) also screenshots here - i was wondering if you can do them with e. at least the titlebar will match/be consistent with the content. :) > cedric pushed a commit to branch master. > > http://git.enlightenment.org/website/www-content.git/commit/?id=14666b3336d583e0d2ee1e4a73348fcb29841304 > > commit 14666b3336d583e0d2ee1e4a73348fcb29841304 > Author: Clément Bénier <clement.ben...@openwide.fr> > Date: Thu Jun 11 09:28:29 2015 +0200 > > Wiki page enlightenment-debugging created > > Signed-off-by: Clément Bénier <clement.ben...@openwide.fr> > Signed-off-by: Pierre Le Magourou <pierre.lemagou...@openwide.fr> > Signed-off-by: Cedric BAIL <ced...@osg.samsung.com> > --- > pages/debugging/enlightenment_debugging.txt | 264 +++++++++++++++++++++++++++ > + pages/docs.txt | 7 + > 2 files changed, 271 insertions(+) > > diff --git a/pages/debugging/enlightenment_debugging.txt > b/pages/debugging/enlightenment_debugging.txt new file mode 100644 > index 0000000..7f953f2 > --- /dev/null > +++ b/pages/debugging/enlightenment_debugging.txt > @@ -0,0 +1,264 @@ > +~~Title: Enlightenment debugging~~ > +==== Enlightenment Debugging === > + > +This tutorial aims at providing a comprehensive and reproducible > documentation +to debug Enlightenment. It is divided in two sections: > + * [[enlightenment_debugging#Debugging_Enlightenment_using_Gdb|Gdb]] > + * [[enlightenment_debugging#Valgrind|Valgrind]] > + > +Before debugging make sure your debug symbols are enabled, if not, go to the > +[[/docs-efl-start#Enable_debug_symbols_Optional|Enable debug symbols]] > +section. > + > + > +=== Debugging Enlightenment using Gdb === > + > +In order to use gdb, we will simulate a crash in Enlightenment. > + > +Start by running Enlightenment on a machine. Then switch to another tty > +(CTRL+ALT+F1 for tty1). > + > +At that point, 2 processes are interesting, enlightenment and > +enlightenment_start. Indeed, enlightenment is traced by enlightenment_start. > + > +Then setup SEGV to segfault enlightenment. > +<code c> > +kill -SIGSEGV $(pidof enlightenment) > +</code> > + > +enlightenment_start will open a pop-up named Enlightenment Error. > +This pop-up indicates that Enlightenment segfaulted and allows to recover or > +log out but also detaches from the child process (enlightenment) and let > +advanced users use gdb to debug it. > +<code bash> > +#gdb on the running enlightenment process > +gdb enlightenment $(pidof enlightenment) > +</code> > + > +After a bit a prompt is available, if you want, you can save the > +traces in a log: > +<code bash> > +#save the traces in log.txt > +set logging file log.txt > +set logging on > +</code> > + > +== Backtrace == > + > +Use the backtrace command to get information about frames to > +know where the segfault is coming from. > + > +<code bash> > +(gdb) bt > +#0 0xb7d539f8 in select () from /lib/tls/libc.so.6 > +#1 0xb7dff66a in _XEnq () from /usr/X11R6/lib/libX11.so.6 > +#2 0xb7dffa7e in _XRead () from /usr/X11R6/lib/libX11.so.6 > +#3 0xb7e01795 in _XReadEvents () from /usr/X11R6/lib/libX11.so.6 > +#4 0xb7defa88 in XNextEvent () from /usr/X11R6/lib/libX11.so.6 > +#5 0x0809b698 in e_alert_show ( > + text=0x80a34f0 "This is very bad. Enlightenment has segfaulted.\nThis > + is not meant to happen and is likely a > + sign of a\nbug in Enlightenment > + or the libraries it relies on.\n\nYou can gdb attach to this process > + now to try"...) > + at e_alert.c:136 > +#6 0x0808f706 in e_sigseg_act (x=11, info=0x80a9fb0, data=0x80aa030) > + at e_signals.c:54 > +#7 <signal handler called> > +#8 0xb7d539f8 in select () from /lib/tls/libc.so.6 > +#9 0xb7f814ee in _ecore_main_select (timeout=0) > + at ecore_main.c:338 > +#10 0xb7f819ba in _ecore_main_loop_iterate_internal (once_only=0) > + at ecore_main.c:575 > +#11 xb7f81a2b in ecore_main_loop_begin () at ecore_main.c:79 > +#12 0x08059bb3 in main (argc=1, argv=0xbffff144) at e_main.c:551 > +</code> > + > +As you can see in the stack trace, gdb finds the segfault in libc and pops > to the +main function in e_main. But it doesn't seem credible to have a bug > in libc or +x, the important thing is Enlightenment has its own segfault > handler which is +very explicit on frame 5. > + > +The e_sigseg_act() function at frame 6 is called directly from the kernel > when +the program segfaults, meaning enlightenment causes the > +segfault. So, the > +segfault comes from the select function (a libc function) at frame 8 called > in +_e_core_main_select_function at frame 9. > + > +== Go in a frame == > + > +So, the reason of segfault seems to be at frame 9, when //select// function > is +called. Let's go to frame 9: > + > +<code bash> > +fr 9 > +#9 0xb7f814ee in _ecore_main_select (timeout=0) at ecore_main.c:338 > +338 ret = select(max_fd + 1, &rfds, &wfds, &exfds, t); > +(gdb) l > +333 } > +334 } > +335 #ifndef WIN32 > +336 if (_ecore_signal_count_get()) return -1; > +337 #endif > +338 ret = select(max_fd + 1, &rfds, &wfds, &exfds, t); > +339 if (ret < 0) > +340 { > +341 if (errno == EINTR) return -1; > +342 } > +</code> > + > +The first command **//fr 9//** gives useful information: name of the file, > +number of the line, the function called, ... > +The second command **//l//** lists the code around the called function. > +Another useful command allows to print the variables, the parameters, helping > +you to find out the problem, a wrong parameter, a null pointer,... > + > +<code bash> > +(gdb) p ret > +$1 = -4 > +(gdb) p rfds > +$2 = {__fds_bits = {1280, 0 <repeats 31 times>}} > +(gdb) p wfds > +$3 = {__fds_bits = {0 <repeats 32 times>}} > +(gdb) p exfds > +$4 = {__fds_bits = {0 <repeats 32 times>}} > +</code> > + > +Gdb is important to start debugging, it will help you to resize the problem > +even if sometimes is not enough. > + > +---- > + > +=== Valgrind === > + > +Valgrind aims at finding memory problems but for that Enlightenment needs to > be run +through Valgrind. > + > +== Prerequisites == > + > +This tutorial will present 3 different ways to run enlightenment through > valgrind: > + * remote debugging > + * Xephyr invocation > + * Xinit invocation > + > +The easiest way is certainly Xephyr because it allows to target a window on a > +X server host, sadly Xephyr doesn't yet support OpenGL and any issue that may > +be related to it will need to use the Xinit version. > + > +== Remote Debugging == > + > +Enlightenment_start launcher will handle > +setting up environment variables, paths, and launching any other required > +services before Enlightenment starts. > +Fortunately, there are some options in enlightenment_start that allow to run > +Enlightenment through valgrind: > + > +<code bash> > +$enlightenment_start --help > +Options: > + -valgrind[=MODE] > + Run enlightenment from inside valgrind, mode is OR of: > + 1 = plain valgrind to catch crashes (default) > + 2 = trace children (thumbnailer, efm slaves, ...) > + 4 = check leak > + 8 = show reachable after processes finish. > + all = all of above > + -massif > + Run enlightenment from inside massif valgrind tool. > + -callgrind > + Run enlightenment from inside callgrind valgrind tool. > + -valgrind-log-file=<FILENAME> > + Save valgrind log to file, see valgrind's --log-f > +</code> > + > +First of all, get the ip address of your host machine and connect to it, then > +on the distant machine, launch X: > + > +<code bash> > +#launch X on tty1 > +sudo X -ac :1 & > +</code> > + > +For example, If you want to check leak and save traces in a log file : > + > +<code bash> > +export DISPLAY=:1 > +enlightenment_start -valgrind=4 -valgrind-log-file=log.txt > +</code> > + > +At that point, Enlightenment should have started on your host machine. If the > +session is closed then the summary of valgrind should look like : > + > +<code bash> > +==1488== > +==1488== HEAP SUMMARY: > +==1488== in use at exit: 4,479,487 bytes in 24,302 blocks > +==1488== total heap usage: 336,239 allocs, 311,937 frees, 88,068,674 bytes > allocated +==1488== > +==1488== LEAK SUMMARY: > +==1488== definitely lost: 825 bytes in 15 blocks > +==1488== indirectly lost: 39 bytes in 2 blocks > +==1488== possibly lost: 384 bytes in 1 blocks > +==1488== still reachable: 4,478,239 bytes in 24,284 blocks > +==1488== suppressed: 0 bytes in 0 blocks > +==1488== Rerun with --leak-check=full to see details of leaked memory > +==1488== > +==1488== For counts of detected and suppressed errors, rerun with: -v > +==1488== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0) > +</code> > + > +== Valgrind Invocation - xinit == > + > +Create a file called .xinitrc-debug in your home with the following content: > + > +<code bash> > +#!/bin/sh > + > +ulimit -c unlimited > + > +log_file="$HOME/enlightenment-xinit-debug-valgrind.log" > +#path of you installation > +enlightenment_install_path=/usr/local > + > +#set vars > +LD_LIBRARY_PATH="$enlightenment_install_path/lib" > +PATH="$enlightenment_install_path/bin:$PATH" > + > +#log to file > +echo "using installation at $enlightenment_install_path" > +echo "LD_LIBRARY_PATH=$LD_LIBRARY_PATH" > $log_file > +echo "PATH=$enlightenment_install_path/bin: ... " >> $log_file > + > +#start e with valgrind > +$enlightenment_install_path/bin/enlightenment_start -valgrind 2>&1 | tee -a > "$log_file" +</code> > + > +You can now start a debugging session, after X was closed if it is not the > +case log out: > + > +<code bash> > +/usr/bin/xinit ~/.xinitrc-debug -- :1 -nolisten tcp > +</code> > + > +== Valgrind Invocation - Xephyr == > + > +Xephyr is a display server implementing the X11 display server protocol which > +targets a window on a X Server host. So, for this it is important that X is > +launched, you can even do it in your usual window manager under X. > + > +Of course, you need to install Xephyr. > + > +<code bash> > +Xephyr -ac -br -noreset -screen 800x600 :1 > +</code> > + *ac: disable access control restrictions > + *br: create root window with black background > + *noreset: don't reset after last client exists > + *screen 800x600: Specify screen characteristics > + > +A black screen should now be displayed, and the interesting thing for us is > +that you can launch a window manager on it with valgrind in addition: > + > +<code bash> > +DISPLAY=:1 enlightenment_start -valgrind > +</code> > diff --git a/pages/docs.txt b/pages/docs.txt > index 813ebe0..4d44943 100644 > --- a/pages/docs.txt > +++ b/pages/docs.txt > @@ -25,6 +25,13 @@ course you can use stable packages for your distribution > as well. > * [[docs/efl/start|Get started with EFL]] > * [[docs/efl/advanced/start|Advanced EFL Topics]] > > +Go check the current available version of EFL on each distro/platform: > +[[https://phab.enlightenment.org/w/packaging_status/|Table of current > version of EFL]] + > +=== Debugging === > + > + * [[debugging/enlightenment_debugging|Enlightenment debugging]] > + > ---- > > ==== API Documentation ==== > > -- > > -- ------------- Codito, ergo sum - "I code, therefore I am" -------------- The Rasterman (Carsten Haitzler) ras...@rasterman.com ------------------------------------------------------------------------------ Monitor 25 network devices or servers for free with OpManager! OpManager is web-based network management software that monitors network devices and physical & virtual servers, alerts via email & sms for fault. Monitor 25 devices for free with no restriction. Download now http://ad.doubleclick.net/ddm/clk/292181274;119417398;o _______________________________________________ enlightenment-devel mailing list enlightenment-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/enlightenment-devel
