Home » Mailing list archives » linux-kernel » 2010 » August » 30

Possible regression with skb_clone() in 2.6.36

Previous thread: [PATCH] Bluetooth: Simplify L2CAP Streaming mode sending by Gustavo F. Padovan on Monday, August 30, 2010 - 4:10 pm. (1 message)

Next thread: Re: [PATCH v2] GPIO: add support for 74HC164 serial-in/parallel-out 8-bit shift register by David Brownell on Monday, August 30, 2010 - 4:43 pm. (5 messages)
[view original message]
From: Gustavo F. Padovan
Subject: Possible regression with skb_clone() in 2.6.36
Date: Monday, August 30, 2010 - 4:10 pm

I've been experiencing some problems when running the L2CAP Streaming mode in
2.6.36. The system quickly runs in an Out Of Memory condition and crash. That
wasn't happening before, so I think we may have a regression here (I didn't find
where yet). The crash log is below.

The following patch does not fix the regression, but shows that removing the
skb_clone() call from l2cap_streaming_send() makes the problem goes away. The
patch is good anyway since it saves memory and time when sending Streaming mode
packets.


[ 5066.137533] Bluetooth: L2CAP ver 2.15
[ 5066.137873] Bluetooth: L2CAP socket layer initialized
[ 5066.545179] Bluetooth: RFCOMM TTY layer initialized
[ 5066.545879] Bluetooth: RFCOMM socket layer initialized
[ 5066.546582] Bluetooth: RFCOMM ver 1.11
[ 5092.268021] l2test invoked oom-killer: gfp_mask=0x4d0, order=0, oom_adj=0, oom_score_adj=0
[ 5092.268872] Pid: 3897, comm: l2test Not tainted 2.6.36-rc3 #5
[ 5092.269863] Call Trace:
[ 5092.270265]  [<ffffffff8138b6a6>] ? _raw_spin_unlock+0x26/0x30
[ 5092.270878]  [<ffffffff810c0827>] T.427+0x77/0x1e0
[ 5092.271874]  [<ffffffff811b85e7>] ? security_real_capable_noaudit+0x37/0x60
[ 5092.272956]  [<ffffffff810c0e3a>] out_of_memory+0x2ca/0x2f0
[ 5092.273894]  [<ffffffff810c3d43>] __alloc_pages_nodemask+0x693/0x6b0
[ 5092.274871]  [<ffffffff810ea3e6>] cache_alloc_refill+0x2d6/0x5c0
[ 5092.275864]  [<ffffffff810ea805>] __kmalloc+0x135/0x150
[ 5092.276876]  [<ffffffff8130f2ae>] __alloc_skb+0x6e/0x150
[ 5092.277865]  [<ffffffff810d3a00>] ? might_fault+0x40/0x90
[ 5092.278652]  [<ffffffff8130ace2>] sock_alloc_send_pskb+0x1c2/0x320
[ 5092.278927]  [<ffffffff810d3a00>] ? might_fault+0x40/0x90
[ 5092.279864]  [<ffffffff81312add>] ? memcpy_fromiovec+0x6d/0x90
[ 5092.280864]  [<ffffffff8130ae50>] sock_alloc_send_skb+0x10/0x20
[ 5092.281867]  [<ffffffffa00e600f>] l2cap_create_iframe_pdu+0x9f/0x2c0 [l2cap]
[ 5092.282865]  [<ffffffffa00e84b9>] l2cap_sock_sendmsg+0x5d9/0x910 [l2cap]
[ 5092.283932]  [<ffffffff8138ba3c>] ? ...
[ message continues ]
[view original message]
From: Gustavo F. Padovan
Subject: Re: Possible regression with skb_clone() in 2.6.36
Date: Monday, September 20, 2010 - 9:10 pm

I did some progress and found that this really fix the bug. We are fine
here then. :)

-- 
Gustavo F. Padovan
ProFUSION embedded systems - http://profusion.mobi
--


[ message continues ]
Previous thread: [PATCH] Bluetooth: Simplify L2CAP Streaming mode sending by Gustavo F. Padovan on Monday, August 30, 2010 - 4:10 pm. (1 message)

Next thread: Re: [PATCH v2] GPIO: add support for 74HC164 serial-in/parallel-out 8-bit shift register by David Brownell on Monday, August 30, 2010 - 4:43 pm. (5 messages)