netdev - FW: System Hang while trying to send over TCP socket with very less free m/m

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <BLU141-W7E99313C2CA3BE069EC5DD4120@phx.gbl>
Date:	Wed, 29 Jul 2009 13:54:27 +0530
From:	manu gautam <manugautam25@...mail.com>
To:	<netdev@...r.kernel.org>, LKML <linux-kernel@...r.kernel.org>
Subject: FW: System Hang while trying to send over TCP socket with very less
 free m/m

Hi,

I am running 2.6.12 kernel with kernel PREEMPTION being OFF. 
While sending data over TCP socket I am experiencing system hang. What is happening actually is that the system is low in free memory and the sk_stream_alloc_pskb call in tcp_sendmsg fails and the control goes to "sk_stream_wait_memory" function. Inside this function we are calling schedule_timeout only if "sk_stream_memory_free(sk) && vm_wait" check is false. In my case what happens is that this check is always true and we don't do schedule_timeout which results in the system hang.
With preemption being OFF it becomes a kind of deadlock where the one thread is waiting for the memory to be freed but it is not getting scheduled out. 

I also checked on the latest kernel but there also I dont see any fix for this issue. 

Please excuse me if I have pasted it to some wrong mailing list.
Regards,Manu
_________________________________________________________________
Missed any of the IPL matches ? Catch a recap of all the action on MSN Videos
http://msnvideos.in/iplt20/msnvideoplayer.aspx--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html