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gerrit.osmocom.org / libosmocore / 843a84c42550e71322332d9d31c4842d73241112
commit843a84c42550e71322332d9d31c4842d73241112[log] [tgz]
authorPau Espin Pedrol <pespin@sysmocom.de>Wed Nov 03 17:31:47 2021 +0100
committerPau Espin Pedrol <pespin@sysmocom.de>Wed Nov 03 17:43:19 2021 +0100
tree514d990e0135d89c76e96cfe1cc3807deb30bff9
parent36c69ed2564c5b7b4c9c52d278a2426e126c17e9 [diff]
logging: Fix double lock of log_tgt_mutex

Recent commit introduced the "blocking-io" param to "log stderr" VTY
command, which calls log_target_file_switch_to_{stream,wqueue}.
The VTY command already locks the log_tgt_mutex mutex, since it has to
access the tgt list. However, the functions mention above also want to
lock the same mutex in order to log information. Let's drop the logging
to avoid the double lock, and update its documentation to mention it
must be called with the lock already held, as documented on other
similar functions.

The issue can be spotted when running osmo-trx-uhd:
"""
(gdb) bt
 #0  0x00007ffff75d7600 in __lll_lock_wait () from /usr/lib/libpthread.so.0
 #1  0x00007ffff75d0503 in pthread_mutex_lock () from /usr/lib/libpthread.so.0
 #2  0x00007ffff66314fb in log_tgt_mutex_lock_impl () at /git/libosmocore/src/logging.c:130
 #3  0x00007ffff6638e74 in log_check_level (subsys=8, subsys@entry=-1, level=level@entry=3) at /git/libosmocore/src/logging.c:1510
 #4  0x00007ffff6639c91 in log_target_file_switch_to_wqueue (target=target@entry=0x611000000320) at /git/libosmocore/src/logging.c:1186
 #5  0x00007ffff68565d3 in cfg_log_stderr (self=<optimized out>, vty=0x6140000018a0, argc=0, argv=<optimized out>) at /git/libosmocore/src/vty/logging_vty.c:859
 #6  0x00007ffff683db3d in cmd_execute_command_strict (vline=0x60b0000dfe80, vty=vty@entry=0x6140000018a0, cmd=cmd@entry=0x0) at /git/libosmocore/src/vty/command.c:2768
 7  0x00007ffff683e396 in config_from_file (vty=vty@entry=0x6140000018a0, fp=fp@entry=0x615000036400) at /git/libosmocore/src/vty/command.c:2880
 8  0x00007ffff684cedb in vty_read_config_filep (confp=confp@entry=0x615000036400, priv=priv@entry=0x0) at /git/libosmocore/src/vty/vty.c:1529
 9  0x00007ffff684ebfc in vty_read_config_file (file_name=0x7fffffffe7d8 "/build/new/conf/osmo-trx-uhd.cfg", priv=0x0) at /git/libosmocore/src/vty/vty.c:1920
 10 0x0000555555565270 in main (argc=3, argv=0x7fffffffe3c8) at /git/osmo-trx/Transceiver52M/osmo-trx.cpp:652
"""

Debugged by rebuilding libosmocore with "LOG_MTX_DEBUG 1":
"""
/libosmocore/src/logging.c:1510 [log_check_level] lock
/libosmocore/src/logging.c:1522 [log_check_level] unlock
/libosmocore/src/vty/logging_vty.c:844 [cfg_log_stderr] lock
/libosmocore/src/logging.c:1510 [log_check_level] lock
"""
Fixes: b72867f0e68c96ca25e1f9929ce92be0a802db6b
Related: OS#4311
Change-Id: Idb4215fa2f364e28c0bb73fb9975b6c9f50a46f6
1 file changed
tree: 514d990e0135d89c76e96cfe1cc3807deb30bff9
  1. contrib/
  2. debian/
  3. doc/
  4. include/
  5. m4/
  6. src/
  7. tapset/
  8. tests/
  9. utils/
  10. .gitignore
  11. .gitreview
  12. .mailmap
  13. configure.ac
  14. COPYING
  15. Doxyfile.codec.in
  16. Doxyfile.coding.in
  17. Doxyfile.core.in
  18. Doxyfile.ctrl.in
  19. Doxyfile.gb.in
  20. Doxyfile.gsm.in
  21. Doxyfile.vty.in
  22. git-version-gen
  23. libosmocodec.pc.in
  24. libosmocoding.pc.in
  25. libosmocore.pc.in
  26. libosmoctrl.pc.in
  27. libosmogb.pc.in
  28. libosmogsm.pc.in
  29. libosmosim.pc.in
  30. libosmousb.pc.in
  31. libosmovty.pc.in
  32. Makefile.am
  33. osmo-release.mk
  34. osmo-release.sh
  35. README.md
  36. TODO-RELEASE
README.md

libosmocore - set of Osmocom core libraries

This repository contains a set of C-language libraries that form the core infrastructure of many Osmocom Open Source Mobile Communications projects.

Historically, a lot of this code was developed as part of the OpenBSC project, but which are of a more generic nature and thus useful to (at least) other programs that we develop in the sphere of Free Software / Open Source mobile communications.

There is no clear scope of it. We simply move all shared code between the various Osmocom projects in this library to avoid code duplication.

The libosmocore.git repository build multiple libraries:

  • libosmocore contains some general-purpose functions like select-loop abstraction, message buffers, timers, linked lists
  • libosmovty contains routines related to the interactive command-line interface called VTY
  • libosmogsm contains definitions and helper code related to GSM protocols
  • libosmoctrl contains a shared implementation of the Osmocom control interface
  • libosmogb contains an implementation of the Gb interface with its NS/BSSGP protocols
  • libosmocodec contains an implementation of GSM voice codecs
  • libosmocoding contains an implementation of GSM channel coding
  • libosmosim contains infrastructure to interface SIM/UICC/USIM cards

Homepage

The official homepage of the project is https://osmocom.org/projects/libosmocore/wiki/Libosmocore

GIT Repository

You can clone from the official libosmocore.git repository using

git clone git://git.osmocom.org/libosmocore.git

There is a cgit interface at https://git.osmocom.org/libosmocore/

Documentation

Doxygen-generated API documentation is generated during the build process, but also available online for each of the sub-libraries at https://ftp.osmocom.org/api/latest/libosmocore/

Mailing List

Discussions related to libosmocore are happening on the openbsc@lists.osmocom.org mailing list, please see https://lists.osmocom.org/mailman/listinfo/openbsc for subscription options and the list archive.

Please observe the Osmocom Mailing List Rules when posting.

Contributing

Our coding standards are described at https://osmocom.org/projects/cellular-infrastructure/wiki/Coding_standards

We us a gerrit based patch submission/review process for managing contributions. Please see https://osmocom.org/projects/cellular-infrastructure/wiki/Gerrit for more details

The current patch queue for libosmocore can be seen at https://gerrit.osmocom.org/#/q/project:libosmocore+status:open