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Ticket #2418 (new defect)

Opened 12 years ago

Last modified 12 years ago

fragmentation bug: system crashes when sending packet larger than fragment threshold

Reported by: Assigned to:
Priority: major Milestone:
Component: madwifi: driver Version: trunk
Keywords: fragmentation Cc:
Patch is attached: 1 Pending: 0


My system info:

tung@wlan-proj-5:~$ uname -r

tung@wlan-proj-5:~$ svn info madwifi_source_01/madwifi/
Path: madwifi_source_01/madwifi
URL: //
Repository Root://
Repository UUID: 0192ed92-7a03-0410-a25b-9323aeb14dbd
Revision: 4133
Node Kind: directory
Schedule: normal
Last Changed Author: proski
Last Changed Rev: 4132
Last Changed Date: 2010-06-20 04:27:20 +1000 (Sun, 20 Jun 2010)

tung@wlan-proj-5:~$ lspci
******omit output*********
01:00.0 Network controller: Atheros Communications Inc. AR928X Wireless Network Adapter (PCI-Express) (rev 01)
03:00.0 Ethernet controller: Atheros Communications Atheros AR8132 / L1c Gigabit Ethernet Adapter (rev c0)

tung@wlan-proj-5:~$ modinfo ath_pci | grep version
version:        svn r4132 (trunk)
srcversion:     613E75CA7DE8AB1A1DE9EC3
vermagic:       2.6.32-22-generic SMP mod_unload modversions 586 

This is the bug:

root@wlan-proj-5:~# iwconfig ath0 frag 512
root@wlan-proj-5:~# iwconfig 
lo        no wireless extensions.

wifi0     no wireless extensions.

ath0      IEEE 802.11g  ESSID:"AP605"  
          Mode:Managed  Frequency:2.412 GHz  Access Point: 00:0F:66:90:AD:0D   
          Bit Rate:11 Mb/s   Tx-Power:13 dBm   Sensitivity=1/1  
          Retry:off   RTS thr:off   Fragment thr=512 B   
          Encryption key:1111-1111-11   Security mode:restricted
          Power Management:off
          Link Quality=33/70  Signal level=-60 dBm  Noise level=-93 dBm
          Rx invalid nwid:69797  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

eth5      no wireless extensions.

root@wlan-proj-5:~# ping -c 1 -s 1000
*****system crashes here*********


fragment_patch_01.diff (493 bytes) - added by on 07/23/10 05:20:18.
change the way to allocate memory for fragment packets
fragment_patch_02.diff (0.8 kB) - added by on 07/23/10 05:28:22.
add lock to fix the bug \n Signed-off-by: Tung M Le <>

Change History

07/23/10 05:20:18 changed by

  • attachment fragment_patch_01.diff added.

change the way to allocate memory for fragment packets

07/23/10 05:28:22 changed by

  • attachment fragment_patch_02.diff added.

add lock to fix the bug \n Signed-off-by: Tung M Le <>

07/23/10 05:35:49 changed by

The two patches above fix the bug. At least, the system does not crash anymore. But I do not know which one is the right way to fix this bug. Can anyone give me a detail explanation?