Messages in this thread | | | Date | Wed, 02 Jun 2010 18:13:43 +0530 | From | David John <> | Subject | Re: [2.6.35-rc1 BUG]: Calling sched_clock causes stack trace with DEBUG_PREEMPT |
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On 06/01/2010 03:53 PM, Jens Axboe wrote: > On Tue, Jun 01 2010, David John wrote: >> On 06/01/2010 12:15 PM, David John wrote: >>> Hi, >>> >>> I get stack traces like the following: >>> >>> BUG: using smp_processor_id() in preemptible [00000000] code: init/1 >>> caller is native_sched_clock+0x37/0x6d >>> Pid: 1, comm: init Not tainted 2.6.35-rc1 #99 >>> Call Trace: >>> [<ffffffff811c422b>] debug_smp_processor_id+0xd3/0xec >>> [<ffffffff81008a1e>] native_sched_clock+0x37/0x6d >>> [<ffffffff811a7bfd>] blk_rq_init+0x92/0x9e >>> [<ffffffff811a7f2e>] get_request+0x1c8/0x27e >>> [<ffffffff811a8011>] get_request_wait+0x2d/0x13c >>> [<ffffffff810306ee>] ? get_parent_ip+0x11/0x42 >>> [<ffffffff81411ea6>] ? add_preempt_count+0xad/0xb1 >>> [<ffffffff811a83b3>] __make_request+0x293/0x3b8 >>> [<ffffffff81099737>] ? mempool_alloc_slab+0x10/0x12 >>> [<ffffffff811a6bc4>] generic_make_request+0x187/0x1ea >>> [<ffffffff810306ee>] ? get_parent_ip+0x11/0x42 >>> [<ffffffff811a6ce5>] submit_bio+0xbe/0xc7 >>> [<ffffffff810f1f37>] submit_bh+0xef/0x111 >>> [<ffffffff810f4865>] block_read_full_page+0x1ec/0x20c >>> [<ffffffff810f6815>] ? blkdev_get_block+0x0/0x5e >>> [<ffffffff81411de6>] ? sub_preempt_count+0x92/0xa5 >>> [<ffffffff810a0500>] ? __lru_cache_add+0x73/0x93 >>> [<ffffffff810f6e81>] blkdev_readpage+0x13/0x15 >>> [<ffffffff8109f981>] __do_page_cache_readahead+0x161/0x194 >>> [<ffffffff8109f9d0>] ra_submit+0x1c/0x20 >>> [<ffffffff8109fc5f>] ondemand_readahead+0x1bb/0x1ce >>> [<ffffffff810973c9>] ? rcu_read_unlock+0xe/0x29 >>> [<ffffffff8109fd46>] page_cache_sync_readahead+0x38/0x3a >>> [<ffffffff810993c2>] generic_file_aio_read+0x24d/0x57f >>> [<ffffffff810cf973>] ? __mem_cgroup_try_charge+0x78/0x46c >>> [<ffffffff810d2aa0>] do_sync_read+0xc6/0x103 >>> [<ffffffff810306ee>] ? get_parent_ip+0x11/0x42 >>> [<ffffffff810adca5>] ? handle_mm_fault+0x7cb/0x7e5 >>> [<ffffffff810f69c5>] ? block_ioctl+0x32/0x36 >>> [<ffffffff81189fcc>] ? selinux_file_permission+0x57/0xae >>> [<ffffffff81184524>] ? security_file_permission+0x11/0x13 >>> [<ffffffff810d34af>] vfs_read+0xa6/0x103 >>> [<ffffffff810d35c2>] sys_read+0x45/0x69 >>> [<ffffffff810029ab>] system_call_fastpath+0x16/0x1b >>> >>> Since with commit 9195291e you call 'set_start_time_ns' from >>> 'blk_rq_init' which in turn calls 'sched_clock' with preempt enabled. >>> There are other calls to sched_clock in blk-cgroup.c. Maybe they should >>> be checked as well? >>> >>> Regards, >>> David. >>> >> >> I see this has been reported. Never mind. > > This should fix it for now, if you have time to test, then that would > not hurt.
Yes, this works.
Thanks, David.
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