2011/5/2 Jean-Michel Hautbois <[email protected]>: > 2011/4/30 Philippe Gerum <[email protected]>: >> On Fri, 2011-04-29 at 18:08 +0200, Jean-Michel Hautbois wrote: >>> 2011/4/29 Philippe Gerum <[email protected]>: >>> > On Thu, 2011-04-28 at 10:33 +0200, Jean-Michel Hautbois wrote: >>> >> 2011/4/27 Philippe Gerum <[email protected]>: >>> >> > 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. _______________________________________________ Xenomai-core mailing list [email protected] https://mail.gna.org/listinfo/xenomai-core
