Re: [git pull] scheduler updates for v2.6.24

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To: Gabriel C <nix.or.die@...>, Srivatsa Vaddagiri <vatsa@...>
Cc: Ingo Molnar <mingo@...>, Andrew Morton <akpm@...>, <torvalds@...>, <linux-kernel@...>
Date: Tuesday, October 16, 2007 - 7:31 pm

[ cc'ed Srivatsa ]

On 17/10/2007, Gabriel C <nix.or.die@googlemail.com> wrote:

Gabriel, could you please post a disassembled code for pick_next_task_fair()?
(objdump -d kernel/sched.o and then search for pick_next_task_fair --
copy_and_past)

anyway, my guess is that it's :

                se = pick_next_entity(cfs_rq);
                cfs_rq = group_cfs_rq(se);

'se' _happens_ to be NULL and group_cf_rq(se) does se->my_q and
(according to my calculations) offset(my_q) == 68 (0x44) for x86 32bit
system with CONFIG_SCHEDSTATS=n and CONFIG_FAIR_GROUP_SCHED=y
(according to the config).

that might take place provided put_prev_task_fair() failed for some
reason to insert 'current' (or its corresponding group element) back
into the tree in schedule()... say, due to some inconsistency in
cfs_rq's data.

Srivatsa, that's somewhat similar to another issue that has been
posted earlier today (crash in put_prev_task_fair() -->
__enqueue_task() --> rb_insert_color()) that you are already aware of
...  (/me will continue tomorrow).


-- 
Best regards,
Dmitry Adamushko
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Messages in current thread:
[git pull] scheduler updates for v2.6.24, Ingo Molnar, (Mon Oct 15, 10:17 am)
Re: [git pull] scheduler updates for v2.6.24, Thomas Backlund, (Tue Oct 16, 6:04 am)
Re: [git pull] scheduler updates for v2.6.24, Ingo Molnar, (Tue Oct 16, 6:08 am)
Re: [git pull] scheduler updates for v2.6.24, Ingo Molnar, (Tue Oct 16, 6:12 am)
Re: [git pull] scheduler updates for v2.6.24, Thomas Backlund, (Tue Oct 16, 7:00 am)
Re: [git pull] scheduler updates for v2.6.24, Nick Piggin, (Mon Oct 15, 10:38 pm)
Re: [git pull] scheduler updates for v2.6.24, Ingo Molnar, (Mon Oct 15, 11:04 am)
Re: [git pull] scheduler updates for v2.6.24, Andrew Morton, (Mon Oct 15, 2:35 pm)
Re: [git pull] scheduler updates for v2.6.24, Ingo Molnar, (Mon Oct 15, 2:53 pm)
Re: [git pull] scheduler updates for v2.6.24, Dmitry Adamushko, (Tue Oct 16, 6:38 pm)
Re: [git pull] scheduler updates for v2.6.24, Gabriel C, (Tue Oct 16, 6:13 pm)
Re: [git pull] scheduler updates for v2.6.24, Dmitry Adamushko, (Tue Oct 16, 7:31 pm)
Re: [git pull] scheduler updates for v2.6.24, Gabriel C, (Tue Oct 16, 7:50 pm)