<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Wed, Sep 25, 2013 at 6:58 PM, Ben Greear <span dir="ltr"><<a href="mailto:greearb@candelatech.com" target="_blank">greearb@candelatech.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="im">On 09/25/2013 03:51 PM, Matt Causey wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
Hello,<br>
<br>
We run wpa_supplicant on embedded machines and have today noticed that the supplicant dies with segmentation fault. We are seeing sporadic timeouts from the<br>
infrastructure as well, which may or may not be related. The only change on our side is that we installed in a very dense RF environment with a large number of<br>
BSSIDs. Are there any details pertaining to BSSID count or beacon count that could cause a segmentation fault? I'll start looking in the code but wanted to<br>
ask first so that hopefully someone can point me in a more useful direction. :-)<br>
<br>
Here is a log snippet. It's got to be abbreviated because in some cases we have over 988 BSSIDs visible from the client:<br>
</blockquote>
<br></div>
Can you get a core dump and backtrace (and maybe more info from gdb once<br>
we see the backtrace?)<br></blockquote><div><br></div><div>OK so I did get some info. It might appear that there is some new Information Element in the beacons in this RF environment that's causing the segfault. Not sure:<br>
<br>sudo gdb wpa_supplicant<br>GNU gdb 6.8<br>Copyright (C) 2008 Free Software Foundation, Inc.<br>License GPLv3+: GNU GPL version 3 or later <<a href="http://gnu.org/licenses/gpl.html">http://gnu.org/licenses/gpl.html</a>><br>
This is free software: you are free to change and redistribute it.<br>There is NO WARRANTY, to the extent permitted by law. Type "show copying"<br>and "show warranty" for details.<br>This GDB was configured as "i686-pc-linux-gnu"...<br>
(gdb) run -s -t -Dnl80211 -onl80211 -ddd -i wlan0 -c /var/tmp/nerf.conf<br>Starting program: /usr/local/sbin/wpa_supplicant -s -t -Dnl80211 -onl80211 -ddd -i wlan0 -c /var/tmp/nerf.conf<br>[Thread debugging using libthread_db enabled]<br>
1380211578.212081: ssid - hexdump_ascii(len=7):<br> 61 73 69 6e 32 38 32 asin282 <br>1380211578.212199: bgscan - hexdump_ascii(len=19):<br> 73 69 6d 70 6c 65 3a 36 30 30 3a 2d 36 36 3a 31 simple:600:-66:1<br>
32 30 30 200 <br></div><div>[removed]<br></div><div>1380211578.212699: private_key_passwd - hexdump_ascii(len=29): [REMOVED]<br>1380211578.335831: nl80211: Scan SSID - hexdump_ascii(len=0): [NULL]<br>
<br>1380211587.924526: * SSID - hexdump_ascii(len=7):<br> 61 73 69 6e 32 38 32 asin282 <br>1380211588.042745: nl80211: Scan SSID - hexdump_ascii(len=0): [NULL]<br>1380211589.147182: * SSID - hexdump_ascii(len=7):<br>
61 73 69 6e 32 38 32 asin282 <br><br>1380211589.247747: nl80211: Scan SSID - hexdump_ascii(len=0): [NULL]<br>1380211590.105423: * SSID - hexdump_ascii(len=7):<br> 61 73 69 6e 32 38 32 asin282 <br>
1380211590.222784: nl80211: Scan SSID - hexdump_ascii(len=0): [NULL]<br>[New Thread 0xb73dc6c0 (LWP 16180)]<br><br>Program received signal SIGSEGV, Segmentation fault.<br>[Switching to Thread 0xb73dc6c0 (LWP 16180)]<br>wpa_bss_get_vendor_ie (bss=0x87c0a40, vendor_type=5304833) at bss.c:912<br>
912 bss.c: No such file or directory.<br> in bss.c<br>(gdb) <br>(gdb) <br>(gdb) <br><br><br>(gdb) bt<br>#0 wpa_bss_get_vendor_ie (bss=0x87c0a40, vendor_type=5304833) at bss.c:912<br>#1 0x08086de9 in wpas_select_network_from_last_scan (wpa_s=0x876f468) at events.c:645<br>
#2 0x08087e23 in _wpa_supplicant_event_scan_results (wpa_s=0x876f468, data=0xa) at events.c:1186<br>#3 0x08087ed3 in wpa_supplicant_event_scan_results (wpa_s=0x87cf000, data=0x0) at events.c:1269<br>#4 0x0808893d in wpa_supplicant_event (ctx=0x876f468, event=EVENT_SCAN_RESULTS, data=0xbffbe438) at events.c:2438<br>
#5 0x08099371 in send_scan_event (drv=0x876ffb8, aborted=142320980, tb=0xbffbed50) at ../src/drivers/driver_nl80211.c:1679<br>#6 0x08099d4b in do_process_drv_event (bss=0x87700ac, cmd=34, tb=0xbffbed50) at ../src/drivers/driver_nl80211.c:2201<br>
#7 0x0809a4fc in process_global_event (msg=0x87734d0, arg=0x876ff00) at ../src/drivers/driver_nl80211.c:2346<br>#8 0xb772c47c in nl_cb_call () from /usr/local/lib/libnl.so.1<br>#9 0xb772cb7a in nl_recvmsgs () from /usr/local/lib/libnl.so.1<br>
#10 0x08055173 in eloop_sock_table_dispatch (table=0x80b8bc8, fds=0x877b2e8) at ../src/utils/eloop.c:393<br>#11 0x08055a08 in eloop_run () at ../src/utils/eloop.c:769<br>#12 0x0808163e in wpa_supplicant_run (global=0x876f388) at wpa_supplicant.c:3322<br>
#13 0x0808cc94 in main (argc=Cannot access memory at address 0x87cefff<br>) at main.c:297<br>(gdb) <br><br><br></div><div> Thoughts?<br><br>--<br></div><div>Matt<br><br></div></div></div></div>