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Add developer documentation for WPA_TRACE

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Jouni Malinen 2009-12-23 23:35:33 +02:00
parent 96603e4fe1
commit 3e82a2ed62
1 changed files with 72 additions and 1 deletions
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73
doc/testing_tools.doxygen
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@ -4,7 +4,8 @@
[ \ref eapol_test "eapol_test" |
\ref preauth_test "preauth_test" |
\ref driver_test "driver_test" |
\ref unit_tests "Unit tests" ]
\ref unit_tests "Unit tests" |
\ref wpa_trace "Tracing code" ]
%wpa_supplicant source tree includes number of testing and development
tools that make it easier to test the programs without having to setup
@ -289,4 +290,74 @@ make run-tests
This make target builds and runs each test and terminates with zero
exit code if all tests were completed successfully.
\section wpa_trace Tracing code for developer debuggin
%wpa_supplicant and hostapd can be built with tracing code that will
track and analyze memory allocations and other resource registrations
and certain API uses. If incorrect use is detected, a backtrace of the
call location (and/or allocation location) is shown. This can also be
used to detect certain categories of memory leaks and report them
automatically when the program is terminated. The report will also
include information about forgotten eloop events.
The trace code can be enabled with CONFIG_WPA_TRACE=y build
option. More verbose backtrace information can be generated if libbfd
is available and the binaries are not stripped of symbol
information. This is enabled with CONFIG_WPA_TRACE_BFD=y.
For example, a memory leak (forgotten os_free() call) would show up
like this when the program is terminated:
\verbatim
MEMLEAK[0x82d200]: len 128
WPA_TRACE: memleak - START
[0]: ./wpa_supplicant(os_malloc+0x59) [0x41a5e9]
os_malloc() ../src/utils/os_unix.c:359
[1]: ./wpa_supplicant(os_zalloc+0x16) [0x41a676]
os_zalloc() ../src/utils/os_unix.c:418
[2]: ./wpa_supplicant(wpa_supplicant_init+0x38) [0x48b508]
wpa_supplicant_init() wpa_supplicant.c:2315
[3]: ./wpa_supplicant(main+0x2f3) [0x491073]
main() main.c:252
WPA_TRACE: memleak - END
MEMLEAK: total 128 bytes
\endverbatim
Another type of error that can be detected is freeing of memory area
that was registered for some use and is still be referenced:
\verbatim
WPA_TRACE: Freeing referenced memory - START
[2]: ./wpa_supplicant(os_free+0x5c) [0x41a53c]
os_free() ../src/utils/os_unix.c:411
[3]: ./wpa_supplicant(wpa_supplicant_remove_iface+0x30) [0x48b380]
wpa_supplicant_remove_iface() wpa_supplicant.c:2259
[4]: ./wpa_supplicant(wpa_supplicant_deinit+0x20) [0x48b3e0]
wpa_supplicant_deinit() wpa_supplicant.c:2430
[5]: ./wpa_supplicant(main+0x357) [0x4910d7]
main() main.c:276
WPA_TRACE: Freeing referenced memory - END
WPA_TRACE: Reference registration - START
[1]: ./wpa_supplicant [0x41c040]
eloop_trace_sock_add_ref() ../src/utils/eloop.c:94
[2]: ./wpa_supplicant(wpa_supplicant_ctrl_iface_deinit+0x17) [0x473247]
wpa_supplicant_ctrl_iface_deinit() ctrl_iface_unix.c:436
[3]: ./wpa_supplicant [0x48b21c]
wpa_supplicant_cleanup() wpa_supplicant.c:378
wpa_supplicant_deinit_iface() wpa_supplicant.c:2155
[4]: ./wpa_supplicant(wpa_supplicant_remove_iface+0x30) [0x48b380]
wpa_supplicant_remove_iface() wpa_supplicant.c:2259
[5]: ./wpa_supplicant(wpa_supplicant_deinit+0x20) [0x48b3e0]
wpa_supplicant_deinit() wpa_supplicant.c:2430
[6]: ./wpa_supplicant(main+0x357) [0x4910d7]
main() main.c:276
WPA_TRACE: Reference registration - END
Aborted
\endverbatim
This type of error results in showing backtraces for both the location
where the incorrect freeing happened and the location where the memory
area was marked referenced.
*/