On 2010-06-11 10:55, Ingo Molnar wrote: > > * Jens Axboe <jaxboe@xxxxxxxxxxxx> wrote: > >> On 2010-06-11 10:32, Ingo Molnar wrote: >>> >>> * Jens Axboe <jaxboe@xxxxxxxxxxxx> wrote: >>> >>>> 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@xxxxxx> >>>>>> Date : 2010-06-05 06:15 (4 days old) >>>>> >>>>> This seems to have been introduced by >>>>> >>>>> commit 7cbaef9c83e58bbd4bdd534b09052b6c5ec457d5 >>>>> Author: Ingo Molnar <mingo@xxxxxxx> >>>>> 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@xxxxxxx> >>>>> >>>>> 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. >>> >>> Hm, it's still not entirely fixed, as of 2.6.35-rc2-00131-g7908a9e. With some >>> configs i get bad spinlock warnings during bootup: >>> >>> [ 28.968013] initcall net_olddevs_init+0x0/0x82 returned 0 after 93750 usecs >>> [ 28.972003] calling b44_init+0x0/0x55 @ 1 >>> [ 28.976009] bus: 'pci': add driver b44 >>> [ 28.976374] sda: >>> [ 28.978157] BUG: spinlock bad magic on CPU#1, async/0/117 >>> [ 28.980000] lock: 7e1c5bbc, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0 >>> [ 28.980000] Pid: 117, comm: async/0 Not tainted 2.6.35-rc2-tip-01092-g010e7ef-dirty #8183 >>> [ 28.980000] Call Trace: >>> [ 28.980000] [<41ba6d55>] ? printk+0x20/0x24 >>> [ 28.980000] [<4134b7b7>] spin_bug+0x7c/0x87 >>> [ 28.980000] [<4134b853>] do_raw_spin_lock+0x1e/0x123 >>> [ 28.980000] [<41ba92ca>] ? _raw_spin_lock_irqsave+0x12/0x20 >>> [ 28.980000] [<41ba92d2>] _raw_spin_lock_irqsave+0x1a/0x20 >>> [ 28.980000] [<4133476f>] blkiocg_update_io_add_stats+0x25/0xfb >>> [ 28.980000] [<41335dae>] ? cfq_prio_tree_add+0xb1/0xc1 >>> [ 28.980000] [<41337bc7>] cfq_insert_request+0x8c/0x425 >>> [ 28.980000] [<41ba9271>] ? _raw_spin_unlock_irqrestore+0x17/0x23 >>> [ 28.980000] [<41ba9271>] ? _raw_spin_unlock_irqrestore+0x17/0x23 >>> [ 28.980000] [<41329225>] elv_insert+0x107/0x1a0 >>> [ 28.980000] [<41329354>] __elv_add_request+0x96/0x9d >>> [ 28.980000] [<4132bb8c>] ? drive_stat_acct+0x9d/0xc6 >>> [ 28.980000] [<4132dd64>] __make_request+0x335/0x376 >>> [ 28.980000] [<4132c726>] generic_make_request+0x336/0x39d >>> [ 28.980000] [<410ad422>] ? kmem_cache_alloc+0xa1/0x105 >>> [ 28.980000] [<41089285>] ? mempool_alloc_slab+0xe/0x10 >>> [ 28.980000] [<41089285>] ? mempool_alloc_slab+0xe/0x10 >>> [ 28.980000] [<41089285>] ? mempool_alloc_slab+0xe/0x10 >>> [ 28.980000] [<41089347>] ? mempool_alloc+0x57/0xe2 >>> [ 28.980000] [<4132c804>] submit_bio+0x77/0x8f >>> [ 28.980000] [<410d2cbc>] ? bio_alloc_bioset+0x37/0x94 >>> [ 28.980000] [<410ceb90>] submit_bh+0xc3/0xe2 >>> [ 28.980000] [<410d1474>] block_read_full_page+0x249/0x259 >>> [ 28.980000] [<410d31fb>] ? blkdev_get_block+0x0/0xc6 >>> [ 28.980000] [<41087bfa>] ? add_to_page_cache_locked+0x94/0xb5 >>> [ 28.980000] [<410d3d92>] blkdev_readpage+0xf/0x11 >>> [ 28.980000] [<41088823>] do_read_cache_page+0x7d/0x11a >>> [ 28.980000] [<410d3d83>] ? blkdev_readpage+0x0/0x11 >>> [ 28.980000] [<410888f4>] read_cache_page_async+0x16/0x1b >>> [ 28.980000] [<41088904>] read_cache_page+0xb/0x12 >>> [ 28.980000] [<410e80e1>] read_dev_sector+0x2a/0x63 >>> [ 28.980000] [<410e92e8>] adfspart_check_ICS+0x2e/0x166 >>> [ 28.980000] [<41ba6d55>] ? printk+0x20/0x24 >>> [ 28.980000] [<410e8d23>] rescan_partitions+0x196/0x3e4 >>> [ 28.980000] [<41ba7dc7>] ? __mutex_unlock_slowpath+0x98/0x9f >>> [ 28.980000] [<410e92ba>] ? adfspart_check_ICS+0x0/0x166 >>> [ 28.980000] [<410d4277>] __blkdev_get+0x1e7/0x292 >>> [ 28.980000] [<4133a201>] ? kobject_put+0x14/0x16 >>> [ 28.980000] [<410d432c>] blkdev_get+0xa/0xc >>> [ 28.980000] [<410e81fb>] register_disk+0x94/0xe5 >>> [ 28.980000] [<413326c6>] ? blk_register_region+0x1b/0x20 >>> [ 28.980000] [<41332815>] add_disk+0x57/0x95 >>> [ 28.980000] [<41331fc6>] ? exact_match+0x0/0x8 >>> [ 28.980000] [<4133233f>] ? exact_lock+0x0/0x11 >>> [ 28.980000] [<41643848>] sd_probe_async+0x108/0x1be >>> [ 28.980000] [<41048865>] async_thread+0xf5/0x1e6 >>> [ 28.980000] [<4102cbcb>] ? default_wake_function+0x0/0xd >>> [ 28.980000] [<41048770>] ? async_thread+0x0/0x1e6 >>> [ 28.980000] [<410433df>] kthread+0x5f/0x64 >>> [ 28.980000] [<41043380>] ? kthread+0x0/0x64 >>> [ 28.980000] [<41002cc6>] kernel_thread_helper+0x6/0x10 >>> [ 29.264071] async/1 used greatest stack depth: 2336 bytes left >>> [ 29.267020] bus: 'ssb': add driver b44 >>> [ 29.267072] initcall b44_init+0x0/0x55 returned 0 after 281250 usecs >>> [ 29.267076] calling init_nic+0x0/0x16 @ 1 >>> >>> Caused by the same blkiocg_update_io_add_stats() function. Bootlog and config >>> attached. Reproducible on that sha1 and with that config. >> >> I think I see it, the internal CFQ blkg groups are not properly >> initialized... Will send a patch shortly. > > Cool - can test it with a short turnaround, the bug is easy to reproduce. Thanks, I need to ensure what the best way to solve it is. The problem is that if you have BLK_CGROUP set but don't enable the CFQ cgroup stuff, then you end up calling the real update functions but CFQ has not initialized them. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
