On Mon, May 04, 2015 at 06:06:24PM -0400, Chris Metcalf wrote: > On 5/1/2015 5:23 PM, Frederic Weisbecker wrote: > >On Fri, May 01, 2015 at 03:57:51PM -0400, Chris Metcalf wrote: > > > >>For example, booting with only cpu 0 as a housekeeping core (and > >>therefore all watchdogs 1-35 on my 36-core tilegx are parked), and > >>immediately doing "echo 0 > /proc/sys/kernel/watchdog", I see > >>(via SysRq ^O-l) the first parked watchdog, on cpu 1, hung with: > >> > >> frame 0: 0xfffffff7000f2928 lock_hrtimer_base+0xb8/0xc0 > >> frame 1: 0xfffffff7000f2a28 hrtimer_try_to_cancel+0x40/0x170 > >> frame 2: 0xfffffff7000f2a28 hrtimer_try_to_cancel+0x40/0x170 > >> frame 3: 0xfffffff7000f2b98 hrtimer_cancel+0x40/0x68 > >> frame 4: 0xfffffff70014cce0 watchdog_disable+0x50/0x70 > >> frame 5: 0xfffffff70008c2d0 smpboot_thread_fn+0x350/0x438 > >> frame 6: 0xfffffff700084b28 kthread+0x160/0x178 > >Have you tried to do that before your patchset? > > Yes, it works fine. It requires the presence of the parked threads to trigger the issue. > > >>The config does not have NO_HZ_FULL_ALL or NO_HZ_FULL_SYSIDLE > >>set, and does have RCU_FAST_NO_HZ and RCU_NOCB_CPU_ALL. > >> > >>I don't really know how to start debugging this, but I do know that > >>unparking the threads first avoids the issue :-) > >Do you have CONFIG_PROVE_LOCKING=y ? > > There seems to be some skew between the community version, which is throwing a > bunch of errors when I enable PROVE_LOCKING, and our internal version where some > things are not yet upstreamed but PROVE_LOCKING works :-) > > I'll try to set aside some time to reconcile the two to figure it out. Hi Chris, I was digging this thread back up and wondered what happened. It seems like a v11 was going to materialize? Cheers, Don -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
