On Tue, Jun 21, 2011 at 02:38:34PM +0530, Santosh Shilimkar wrote: > Russell, > > On 6/20/2011 8:24 PM, Santosh Shilimkar wrote: >> On 6/20/2011 7:53 PM, Russell King - ARM Linux wrote: >>> So, as loops_per_jiffy is not local to this function, the compiler has >>> to write out that zero value, before calling calibrate_delay_converge(), >>> and loops_per_jiffy only becomes non-zero _after_ >>> calibrate_delay_converge() >>> has returned. This opens the window and allows the spinlock debugging >>> code to explode. >>> >>> This patch closes the window completely, by only writing to >>> loops_per_jiffy >>> only when we have a real value for it. >>> >>> This allows me to boot 3.0.0-rc3 on Versatile Express (4 CPU) whereas >>> without this it fails with spinlock lockup and rcu problems. >>> >>> init/calibrate.c | 14 ++++++++------ >>> 1 files changed, 8 insertions(+), 6 deletions(-) >>> >> I am away from my board now. Will test this change. > Have tested your change and it seems to fix the crash I > was observing. Are you planning to send this fix for rc5? Yes. I think sending CPUs into infinite loops in the spinlock code is definitely sufficiently serious that it needs to go to Linus ASAP. It'd be nice to have a tested-by line though. >> btw, the online-active race is still open even with this patch close >> and should be fixed. >> > The only problem remains is waiting for active mask before > marking CPU online. Shall I refresh my patch with only > this change then ? I already have that as a separate change. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
