Query about: ARM11 MPCore: preemption/task migration cache coherency
From: George G. Davis <hidden>
Date: 2012-06-05 04:06:56
Hello, On May 9, 2012, at 5:11 AM, bill4carson wrote:
Hi, All I'm using ARM11 MPCore on linux-2.6.34, unfortunately I have random panic/segment fault with task migration. I noticed a patch set [ARM11 MPCore: preemption/task migration cache coherency fixups] to fix such issues in here:
http://lists.infradead.org/pipermail/linux-arm-kernel/2011-October/069851.html It seems there is no follow ups, is there official patch to fix such issues?
Apologies for the delayed reply. Yes, I believe those patches are still needed for ARM11 MPCore, even when not using PREEMPT. I vaguely recall at least two cases where problems occurred w/o those patches, 1) LTP stress would randomly fail, and 2) parallel module loading would invariably oops with a random fault, with results similar to what you've reported later in this thread. The most reliable test case to reproduce the failure was the parallel module loading. LTP stress test runs took a long time to trigger the errors. I'm dusting off the patches and trying to resurrect the test cases to see if I can reproduce the errors on latest kernel.org. I'll followup with results in a day or so. FWIW, I've got LTP stress running on latest kernel.org now but probably should have resurrected the parallel module loading test case instead, as LTP stress may take awhile to reproduce the error, if at all. -- Regards, George
thanks -- Love each day! --bill