On Wed, May 20 2009, Zhang, Yanmin wrote: > On Tue, 2009-05-19 at 08:20 +0200, Jens Axboe wrote: > > On Tue, May 19 2009, Zhang, Yanmin wrote: > > > On Mon, 2009-05-18 at 14:19 +0200, Jens Axboe wrote: > > > > Hi, > > > > > > > > This is the fourth version of this patchset. Chances since v3: > > > > > > > > - Dropped a prep patch, it has been included in mainline since. > > > > > > > > - Add a work-to-do list to the bdi. This is struct bdi_work. Each > > > > wb thread will notice and execute work on bdi->work_list. The arguments > > > > are which sb (or NULL for all) to flush and how many pages to flush. > > > > > > > > - Fix a bug where not all bdi's would end up on the bdi_list, so potentially > > > > some data would not be flushed. > > > > > > > > - Make wb_kupdated() pass on wbc->older_than_this so we maintain the same > > > > behaviour for kupdated flushes. > > > > > > > > - Have the wb thread flush first before sleeping, to avoid losing the > > > > first flush on lazy register. > > > > > > > > - Rebase to newer kernels. > > > I'm attaching two patches - apply #1 to -rc6, and then #2 is a roll-up > > of the patch series that you can apply next. > Jens, > > I run into 2 issues with kernel 2.6.30-rc6+BDI_Flusher_V4. Below is one. > > Tue May 19 00:00:00 CST 2009 > BUG: unable to handle kernel NULL pointer dereference at 00000000000001d8 > IP: [<ffffffff803f3c4c>] generic_make_request+0x10a/0x384 > PGD 0 > Oops: 0000 [#1] SMP > last sysfs file: /sys/block/sdb/stat > CPU 0 > Modules linked in: igb > Pid: 1445, comm: bdi-8:16 Not tainted 2.6.30-rc6-bdiflusherv4 #1 X8DTN > RIP: 0010:[<ffffffff803f3c4c>] [<ffffffff803f3c4c>] generic_make_request+0x10a/0x384 > RSP: 0018:ffff8800bd04da60 EFLAGS: 00010206 > RAX: 0000000000000000 RBX: ffff8801be45d500 RCX: 00000000038a0df8 > RDX: 0000000000000008 RSI: 0000000000000576 RDI: ffff8801bf408680 > RBP: ffff8801be45d500 R08: ffffe20001ee8140 R09: ffff8800bd04da98 > R10: 0000000000000000 R11: ffff8800bd72eb40 R12: ffff8801be45d500 > R13: ffff88005f51f310 R14: 0000000000000008 R15: ffff8800b15a5458 > FS: 0000000000000000(0000) GS:ffffc20000000000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b > CR2: 00000000000001d8 CR3: 0000000000201000 CR4: 00000000000006e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > Process bdi-8:16 (pid: 1445, threadinfo ffff8800bd04c000, task ffff8800bd1b75f0) > Stack: > 0000000000000008 ffffffff8027a613 00000000848dc000 ffffffffffffffff > ffff8800a8190f50 ffffffff00000012 ffff8800a81938e0 ffffc2000000001b > 0000000000000000 0000000000000000 ffffe200026f9c30 0000000000000000 > Call Trace: > [<ffffffff8027a613>] ? mempool_alloc+0x59/0x10f > [<ffffffff803f3f70>] ? submit_bio+0xaa/0xb1 > [<ffffffff802c6a3f>] ? submit_bh+0xe3/0x103 > [<ffffffff802c92ea>] ? __block_write_full_page+0x1fb/0x2f2 > [<ffffffff802c7d6a>] ? end_buffer_async_write+0x0/0xfb > [<ffffffff8027e8d2>] ? __writepage+0xa/0x25 > [<ffffffff8027f036>] ? write_cache_pages+0x21c/0x338 > [<ffffffff8027e8c8>] ? __writepage+0x0/0x25 > [<ffffffff8027f195>] ? do_writepages+0x27/0x2d > [<ffffffff802c22c1>] ? __writeback_single_inode+0x159/0x2b3 > [<ffffffff8071e52a>] ? thread_return+0x3e/0xaa > [<ffffffff8027f267>] ? determine_dirtyable_memory+0xd/0x1d > [<ffffffff8027f2dd>] ? get_dirty_limits+0x1d/0x255 > [<ffffffff802c27bc>] ? generic_sync_wb_inodes+0x1b4/0x220 > [<ffffffff802c3130>] ? wb_do_writeback+0x16c/0x215 > [<ffffffff802c323e>] ? bdi_writeback_task+0x65/0x10d > [<ffffffff8024cc06>] ? autoremove_wake_function+0x0/0x2e > [<ffffffff8024cb27>] ? bit_waitqueue+0x10/0xa0 > [<ffffffff80289257>] ? bdi_start_fn+0x0/0xba > [<ffffffff802892c6>] ? bdi_start_fn+0x6f/0xba > [<ffffffff8024c860>] ? kthread+0x54/0x80 > [<ffffffff8020c97a>] ? child_rip+0xa/0x20 > [<ffffffff8024c80c>] ? kthread+0x0/0x80 > [<ffffffff8020c970>] ? child_rip+0x0/0x20 > > The panic happened at the beginging of a mmap randrw after a mmap randwrite. > > It's triggered in __generic_make_request => bdev_get_queue(bio->bi_bdev), > because ???bio->bi_bdev->bd_disk is equal to NULL. > > The callchain is: > ???bdi_writeback_task => > wb_do_writeback => > ???generic_sync_wb_inodes => > ???__writeback_single_inode => > ... > ???__block_write_full_page => > ???submit_bh => > submit_bio=> > ???generic_make_request Wow, that is really odd. Can you pass the details of the test you ran? -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
