Summary:	DAHLIN-00340: race condition after upgrading to kernel 3.16.2
Reporter:	Thomas B. Clark (tbclark3)	Labels:
Date Opened:	2014-09-14 11:57:46	Date Closed:	2014-09-17 16:31:36
Priority:	Blocker	Regression?
Status:	Closed/Complete	Components:	dahdi (the module)
Versions:	2.10.0	Frequency of Occurrence	Constant
Related Issues:
Environment:	fedora 20 64-bit, wct1_xxp	Attachments:	( 0) 0001-dahdi-Fix-failure-to-read-write-on-kernel-3.16.patch ( 1) dahdi-Fix-failure-to-read-write-on-kernel-3.16-v2.patch
Description:	The dahdi modules load successfully.  However, starting Asterisk results in a race condition that writes the following error at the rate of about 1GB/minute [Sep 14 09:48:16] WARNING[21296] chan_dahdi.c: Read failed with -1: Invalid argument It brings my system to a crawl in about 30 seconds. Downgrading to kernel 3.15.10 resolves the issue. I do not see any other clues in the log.
Comments:	By: Shaun Ruffell (sruffell) 2014-09-15 10:36:46.231-0500 More people are hitting this: http://thread.gmane.org/gmane.comp.telephony.pbx.asterisk.user/281306 By: Shaun Ruffell (sruffell) 2014-09-16 17:16:18.546-0500 I think I see what the offending change in the kernel is. Notes are the comment  of the attached [^0001-dahdi-Fix-failure-to-read-write-on-kernel-3.16.patch]. By: Shaun Ruffell (sruffell) 2014-09-16 17:19:51.645-0500 Thomas, care to confirm this patch works for you as well? By: Thomas B. Clark (tbclark3) 2014-09-16 20:23:35.950-0500 The patch works.  Thanks! By: Shaun Ruffell (sruffell) 2014-09-17 09:52:49.037-0500 Thanks for checking Thomas. Ok, I updated the patch slightly [^dahdi-Fix-failure-to-read-write-on-kernel-3.16-v2.patch] to hopefully make it more clear. I expect it will be in the next release of DAHDI. By: Russ Meyerriecks (rmeyerriecks) 2014-09-17 16:30:56.952-0500 Patch has been committed to master http://git.asterisk.org/gitweb/?p=dahdi/linux.git;a=commitdiff;h=b9a8000bbd1b6120f22627c105a2c2194dcc793d