Re: 2.6.35-rc2-git2: Reported regressions from 2.6.34

Jens Axboe
2010-06-09T07:53:22Z

On 2010-06-09 03:53, Linus Torvalds wrote:
>> Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=16129
>> Subject : BUG: using smp_processor_id() in preemptible [00000000] code: jbd2/sda2
>> Submitter : Jan Kreuzer <kontrollator@gmx.de>
>> Date : 2010-06-05 06:15 (4 days old)
>
> This seems to have been introduced by
>
> commit 7cbaef9c83e58bbd4bdd534b09052b6c5ec457d5
> Author: Ingo Molnar <mingo@elte.hu>
> Date: Sat Nov 8 17:05:38 2008 +0100
>
> sched: optimize sched_clock() a bit
>
> sched_clock() uses cycles_2_ns() needlessly - which is an irq-disabling
> variant of __cycles_2_ns().
>
> Most of the time sched_clock() is called with irqs disabled already.
> The few places that call it with irqs enabled need to be updated.
>
> Signed-off-by: Ingo Molnar <mingo@elte.hu>
>
> and this seems to be one of those calling cases that need to be updated.
>
> Ingo? The call trace is:
>
> BUG: using smp_processor_id() in preemptible [00000000] code: jbd2/sda2-8/337
> caller is native_sched_clock+0x3c/0x68
> Pid: 337, comm: jbd2/sda2-8 Not tainted 2.6.35-rc1jan+ #4
> Call Trace:
> [<ffffffff812362c5>] debug_smp_processor_id+0xc9/0xe4
> [<ffffffff8101059d>] native_sched_clock+0x3c/0x68
> [<ffffffff8101043d>] sched_clock+0x9/0xd
> [<ffffffff81212d7a>] blk_rq_init+0x97/0xa3
> [<ffffffff81214d71>] get_request+0x1c4/0x2d0
> [<ffffffff81214ea6>] get_request_wait+0x29/0x1a6
> [<ffffffff81215537>] __make_request+0x338/0x45b
> [<ffffffff812147c2>] generic_make_request+0x2bb/0x330
> [<ffffffff81214909>] submit_bio+0xd2/0xef
> [<ffffffff811413cb>] submit_bh+0xf4/0x116
> [<ffffffff81144853>] block_write_full_page_endio+0x89/0x96
> [<ffffffff81144875>] block_write_full_page+0x15/0x17
> [<ffffffff8119b00a>] ext4_writepage+0x356/0x36b
> [<ffffffff810e1f91>] __writepage+0x1a/0x39
> [<ffffffff810e32a6>] write_cache_pages+0x20d/0x346
> [<ffffffff810e3406>] generic_writepages+0x27/0x29
> [<ffffffff811ca279>] journal_submit_data_buffers+0x110/0x17d
> [<ffffffff811ca986>] jbd2_journal_commit_transaction+0x4cb/0x156d
> [<ffffffff811d0cba>] kjournald2+0x147/0x37a
>
> (from the bugzilla thing)

This should be fixed by commit 28f4197e which was merged on friday.

>> Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=16122
>> Subject : 2.6.35-rc1: WARNING at fs/fs-writeback.c:1142 __mark_inode_dirty+0x103/0x170
>> Submitter : Larry Finger <Larry.Finger@lwfinger.net>
>> Date : 2010-06-04 13:18 (5 days old)
>
> Jens?

Looking into this one.

--
Jens Axboe