On Mon, 2011-05-02 at 11:56 +0200, Jean-Michel Hautbois wrote: > 2011/5/2 Jean-Michel Hautbois <jhautb...@gmail.com>: > > 2011/4/30 Philippe Gerum <r...@xenomai.org>: > >> On Fri, 2011-04-29 at 18:08 +0200, Jean-Michel Hautbois wrote: > >>> 2011/4/29 Philippe Gerum <r...@xenomai.org>: > >>> > On Thu, 2011-04-28 at 10:33 +0200, Jean-Michel Hautbois wrote: > >>> >> 2011/4/27 Philippe Gerum <r...@xenomai.org>: > >>> >> > On Wed, 2011-04-27 at 20:42 +0200, Jean-Michel Hautbois wrote: > >>> >> >> Hi list, > >>> >> >> > >>> >> >> I am currently using a Xenomai port on a linux 2.6.35.11 linux > >>> >> >> kernel > >>> >> >> and the adeos-ipipe-2.6.35.7-powerpc-2.12-01.patch. > >>> >> >> I am facing a scheduling issue on a P2020 (dual core PowerPC), and I > >>> >> >> get the following message : > >>> >> >> > >>> >> >> Badness at arch/powerpc/mm/mmu_context_nohash.c:209 > >>> >> >> NIP: c0018d20 LR: c039b94c CTR: c00343e4 > >>> >> >> REGS: ecfadce0 TRAP: 0700 Tainted: G W (2.6.35.11) > >>> >> >> MSR: 00021000 <ME,CE> CR: 24000488 XER: 00000000 > >>> >> >> TASK = ec5220d0[496] 'sipaq' THREAD: ecfac000 CPU: 1 > >>> >> >> GPR00: 00000001 ecfadd90 ec5220d0 ec5df340 ec58a700 00000000 > >>> >> >> ffffffff 00000003 > >>> >> >> GPR08: c04a2d98 00000007 c04a2d98 0067e000 0002f385 1007f1f8 > >>> >> >> c04a5b40 ecfac040 > >>> >> >> GPR16: c04a5b40 c04deb80 c04a2120 c04a2d98 c04a5b40 c04d008c > >>> >> >> ecfac000 00029000 > >>> >> >> GPR24: c04d0000 c04d1e6c 00000001 ec58a700 eceaf390 c04d1e78 > >>> >> >> c0b23b40 ec5df340 > >>> >> >> NIP [c0018d20] switch_mmu_context+0x80/0x438 > >>> >> >> LR [c039b94c] schedule+0x774/0x7dc > >>> >> >> Call Trace: > >>> >> >> [ecfadd90] [44000484] 0x44000484 (unreliable) > >>> >> >> [ecfadde0] [c039b94c] schedule+0x774/0x7dc > >>> >> >> [ecfade50] [c039cb98] do_nanosleep+0xc8/0x114 > >>> >> >> [ecfade80] [c0059bf8] hrtimer_nanosleep+0xd8/0x158 > >>> >> >> [ecfadf10] [c0059d48] sys_nanosleep+0xd0/0xd4 > >>> >> >> [ecfadf40] [c0013c0c] ret_from_syscall+0x0/0x3c > >>> >> >> --- Exception: c01 at 0xffa6cc4 > >>> >> >> LR = 0xffa6cb0 > >>> >> >> Instruction dump: > >>> >> >> 40a2fff0 4c00012c 2f800000 409e0128 813b018c 2f830000 39290001 > >>> >> >> 913b018c > >>> >> >> 419e0020 8003018c 7c000034 5400d97e <0f000000> 8123018c 3929ffff > >>> >> >> 9123018c > >>> >> >> > >>> >> >> Do you have a clue on how to start debugging it ? > >>> >> > > >>> >> > Yes, but that can't be easily summarized here. In short, we have a > >>> >> > serious problem with the sharing of the MMU context between the Linux > >>> >> > and Xenomai schedulers in the SMP case on powerpc. > >>> >> > >>> >> OK, good to know that it is a known issue. If there is a thread with > >>> >> some thoughts about it, I am interested ;). > >>> >> > >>> >> >> It is happening quite randomly... :). > >>> >> > > >>> >> > Does disabling CONFIG_XENO_HW_UNLOCKED_SWITCH clear this issue? > >>> >> > > >>> >> > >>> >> Well, yes and no. It starts well, but when booting the kernel I get : > >>> > > >>> > > >>> > The mm switch issue was specifically addressed by this patch, which is > >>> > part of 2.12-01: > >>> > http://git.denx.de/?p=ipipe-2.6.git;a=commit;h=c14a47630d62d0328de1957636dceb1d498f7048 > >>> > > >>> > However, it the last 2.6.35 patch issued was based on 2.6.35.7, not > >>> > 2.6.35.11, so there is still the possibility that something went wrong > >>> > while you forward ported this code. > >>> > > >>> > - Please check that mmu_context_nohash.c does contain the fix above as > >>> > it should > >>> > >>> It is ok, I have the fix. > >> > >> Does 2.6.35.7-2.12-02 exhibit the issue as well? > > > > It doesn't seem to exhibit the issue... I didn't try during a long > > time though... > > > >>> > >>> > - Please try Richard's suggestion, i.e. moving to 2.6.36, which may give > >>> > us more hints. > >>> > >>> It is better. I don't have the badness on mmu context anymore. > >>> This gives some hints ;). > >>> > >> > >> Yes and no. The mmu management code involved was untouched between > >> 2.6.35 and 2.6.36, so I still don't get why this activity counter gets > >> trashed yet. > >> > >>> >> Badness at kernel/lockdep.c:2327 > >>> >> NIP: c006e554 LR: c006e53c CTR: 000186a0 > >>> > > >>> > Adeos sometimes conflicts with the vanilla IRQ state tracer. I'll have a > >>> > look at this. Disable CONFIG_TRACE_IRQFLAGS. > >>> > >>> Yes, but I *want* to have the CONFIG_TRACE_IRQFLAGS on. I just wanted > >>> to tell that I had the problem, in order to be sure it is known ;). > >>> > >> > >> Sure, but one issue at a time. > >> > >>> JM > >> > >> -- > >> Philippe. > >> > > OK, the badness disappears, but the 2.6.36 kernel seems more stable > than 2.6.35 with this patch.
What does "more stable" mean? Do you have lockups, any issue reported in the kernel log? Any weird Xenomai behavior? -- Philippe. _______________________________________________ Xenomai-core mailing list Xenomai-core@gna.org https://mail.gna.org/listinfo/xenomai-core
