Bug 12409

Summary:	NULL pointer dereference at get_stats()
Product:	Networking	Reporter:	Rafael J. Wysocki (rjw)
Component:	IPV4	Assignee:	Stephen Hemminger (stephen)
Status:	RESOLVED DOCUMENTED
Severity:	normal	CC:	alan
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	2.6.28	Subsystem:
Regression:	Yes	Bisected commit-id:
Attachments:	debug patch to print driver

Description Rafael J. Wysocki 2009-01-10 15:38:07 UTC

Subject    : [2.6.28] NULL pointer dereference at get_stats()
Submitter  : Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Date       : 2008-12-30 12:53
References : http://marc.info/?l=linux-kernel&m=123064167008695&w=4
Handled-By : Frederik Deweerdt <frederik.deweerdt@xprog.eu>

This entry is being used for tracking a regression from 2.6.27.  Please don't
close it until the problem is fixed in the mainline.

Comment 1 Thomas Gleixner 2009-01-14 05:30:12 UTC

This happens in the networking code:

EIP is at get_stats+0x1d/0x48
...
[<c05bcc0f>] dev_seq_show+0x1c/0x77

EIP is at get_stats+0x1d/0x48
...
 [<c05c571a>] rtnl_fill_ifinfo+0x2c9/0x498

Reassigning to networking

Comment 2 Stephen Hemminger 2009-01-14 12:18:53 UTC

Created attachment 19798 [details]
debug patch to print driver

Comment 3 Stephen Hemminger 2009-01-14 12:19:05 UTC

Some network driver has incorrectly cleared the get_stats function pointer.
We need more information to figure out which driver is involved.
See attached patch which will print error.

Because things are done in differently in 2.6.29, this will no longer happen.