diff --git a/doc/README.backtrace b/doc/README.backtrace new file mode 100755 index 0000000000000000000000000000000000000000..e0af58e17d6304dbb8520709b6995237ee5acde6 --- /dev/null +++ b/doc/README.backtrace @@ -0,0 +1,170 @@ + + +This document is to provide information on how to obtain the backtraces required on the asterisk bug tracker, available at http://bugs.digium.com. +The information is required by developers to help fix problem with bugs of any kind. +Backtraces provide information about what was wrong when a program crashed; in our case, Asterisk. +There are two kind of backtraces (aka 'bt'), which are useful: bt and bt full. + +First of all, when you start Asterisk, you MUST start it with option -g (this tells Asterisk to produce a core file if it crashes). +If you start Asterisk with the safe_asterisk script, it automatically starts using the option -g. + +If you're not sure if Asterisk is running with the -g option, type the following command in your shell: + +debian:/tmp# ps aux | grep asterisk +root 17832 0.0 1.2 2348 788 pts/1 S Aug12 0:00 /bin/sh /usr/sbin/safe_asterisk +root 26686 0.0 2.8 15544 1744 pts/1 S Aug13 0:02 asterisk -vvvg -c +[...] + +The interesting information is located in the last column. + + +After Asterisk crashes, a core file will be "dumped" in your /tmp/ directory +To make sure it's really there, you can just type the following command in your shell: + +debian:/tmp# ls -l /tmp/core.* +-rw------- 1 root root 10592256 Aug 12 19:40 /tmp/core.26252 +-rw------- 1 root root 9924608 Aug 12 20:12 /tmp/core.26340 +-rw------- 1 root root 10862592 Aug 12 20:14 /tmp/core.26374 +-rw------- 1 root root 9105408 Aug 12 20:19 /tmp/core.26426 +-rw------- 1 root root 9441280 Aug 12 20:20 /tmp/core.26462 +-rw------- 1 root root 8331264 Aug 13 00:32 /tmp/core.26647 +debian:/tmp# + +Now that we've verified the core file has been written to disk, the final part is to extract 'bt' from the core file. +Core files are pretty big, don't be scared, it's normal. + +*** NOTE: Don't attach core files on the bug tracker, we only need the bt and bt full. *** + +For extraction, we use a really nice tool, called gdb. To verify that you have gdb installed on your system: + +debian:/tmp# gdb -v +GNU gdb 6.3-debian +Copyright 2004 Free Software Foundation, Inc. +GDB is free software, covered by the GNU General Public License, and you are +welcome to change it and/or distribute copies of it under certain conditions. +Type "show copying" to see the conditions. +There is absolutely no warranty for GDB. Type "show warranty" for details. +This GDB was configured as "i386-linux". +debian:/tmp# + +Which is great, we can continue. If you don't have gdb installed, go install gdb. + +Now load the core file in gdb, as follows: + +debian:/tmp# gdb -se "asterisk" -c /tmp/core.26252 +[...] +(You would see a lot of output here.) +[...] +Reading symbols from /usr/lib/asterisk/modules/app_externalivr.so...done. +Loaded symbols for /usr/lib/asterisk/modules/app_externalivr.so +#0 0x29b45d7e in ?? () +(gdb) + +Now at the gdb prompt, type: bt +You would see output similar to: +(gdb) bt +#0 0x29b45d7e in ?? () +#1 0x08180bf8 in ?? () +#2 0xbcdffa58 in ?? () +#3 0x08180bf8 in ?? () +#4 0xbcdffa60 in ?? () +#5 0x08180bf8 in ?? () +#6 0x180bf894 in ?? () +#7 0x0bf80008 in ?? () +#8 0x180b0818 in ?? () +#9 0x08068008 in ast_stopstream (tmp=0x40758d38) at file.c:180 +#10 0x000000a0 in ?? () +#11 0x000000a0 in ?? () +#12 0x00000000 in ?? () +#13 0x407513c3 in confcall_careful_stream (conf=0x8180bf8, filename=0x8181de8 "Zap/pseudo-1324221520") at app_meetme.c:262 +#14 0x40751332 in streamconfthread (args=0x8180bf8) at app_meetme.c:1965 +#15 0xbcdffbe0 in ?? () +#16 0x40028e51 in pthread_start_thread () from /lib/libpthread.so.0 +#17 0x401ec92a in clone () from /lib/libc.so.6 +(gdb) + + +The bt's output is the informations that we need on the bug tracker. + +Now do a bt full as follows: +(gdb) bt full +#0 0x29b45d7e in ?? () +No symbol table info available. +#1 0x08180bf8 in ?? () +No symbol table info available. +#2 0xbcdffa58 in ?? () +No symbol table info available. +#3 0x08180bf8 in ?? () +No symbol table info available. +#4 0xbcdffa60 in ?? () +No symbol table info available. +#5 0x08180bf8 in ?? () +No symbol table info available. +#6 0x180bf894 in ?? () +No symbol table info available. +#7 0x0bf80008 in ?? () +No symbol table info available. +#8 0x180b0818 in ?? () +No symbol table info available. +#9 0x08068008 in ast_stopstream (tmp=0x40758d38) at file.c:180 +No locals. +#10 0x000000a0 in ?? () +No symbol table info available. +#11 0x000000a0 in ?? () +No symbol table info available. +#12 0x00000000 in ?? () +No symbol table info available. +#13 0x407513c3 in confcall_careful_stream (conf=0x8180bf8, filename=0x8181de8 "Zap/pseudo-1324221520") at app_meetme.c:262 + f = (struct ast_frame *) 0x8180bf8 + trans = (struct ast_trans_pvt *) 0x0 +#14 0x40751332 in streamconfthread (args=0x8180bf8) at app_meetme.c:1965 +No locals. +#15 0xbcdffbe0 in ?? () +No symbol table info available. +#16 0x40028e51 in pthread_start_thread () from /lib/libpthread.so.0 +No symbol table info available. +#17 0x401ec92a in clone () from /lib/libc.so.6 +No symbol table info available. +(gdb) + + +We also need gdb's output. +That output gives more details compared to the simple "bt". So we recommend that you use bt full instead of bt. +But, if you could include both, we appreciate that. + +The final "extraction" would the to know all traces by all threads. Even if asterisk runs on the same thread for each calls, it could have some new threads created. +To make sure we have the correct informations, just do: +(gdb) thread apply all bt + +Thread 1 (process 26252): +#0 0x29b45d7e in ?? () +#1 0x08180bf8 in ?? () +#2 0xbcdffa58 in ?? () +#3 0x08180bf8 in ?? () +#4 0xbcdffa60 in ?? () +#5 0x08180bf8 in ?? () +#6 0x180bf894 in ?? () +#7 0x0bf80008 in ?? () +#8 0x180b0818 in ?? () +#9 0x08068008 in ast_stopstream (tmp=0x40758d38) at file.c:180 +#10 0x000000a0 in ?? () +#11 0x000000a0 in ?? () +#12 0x00000000 in ?? () +#13 0x407513c3 in confcall_careful_stream (conf=0x8180bf8, filename=0x8181de8 "Zap/pseudo-1324221520") at app_meetme.c:262 +#14 0x40751332 in streamconfthread (args=0x8180bf8) at app_meetme.c:1965 +#15 0xbcdffbe0 in ?? () +#16 0x40028e51 in pthread_start_thread () from /lib/libpthread.so.0 +#17 0x401ec92a in clone () from /lib/libc.so.6 +(gdb) + + +That output tell us crucial informations for threads. + +Now, just create a output.txt and dump your "bt full" (and/or "bt") AND with "thread apply all bt". + +Note: Please ATTACH your output, DO NOT paste it as a note. + +And you're ready for upload on bug tracker. + + +Questions or comments regarding this documentation, feel free to pass by #asterisk-bugs on FreeNode. \ No newline at end of file