On Thu, Nov 12, 2009 at 4:16 AM, Jens Axboe <jens.axboe@xxxxxxxxxx> wrote: > So the device isn't mounted, which means that we'll default to 1k > blocks. I think that's a big clue here, as you'll have 4 buffer_heads > pointing to the same page. And one of your oopses is indeed in the > ->b_this_page unroll. > > Can you trigger this if you mount/umount the device first? Yeah. I've reproduced it reading from /dev/sda (the drive the root partition is mounted on) with no second drive attached, too. I'm currently reproducing it with "dd if=/dev/sda of=/dev/sdb", since that reproduces faster and more reproducably than just reading. Here's a trace from one of these: BUG: unable to handle kernel NULL pointer dereference at 000000c0 IP: [<c1097067>] bdevname+0x8/0x13 *pde = 00000000 Oops: 0000 [#1] PREEMPT last sysfs file: /sys/devices/pci0000:00/0000:00:1f.2/host1/target1:0:0/1:0:0:0/model Modules linked in: netconsole atl1c rtc Pid: 151, comm: pdflush Not tainted (2.6.31.6 #17) G31M-ES2L EIP: 0060:[<c1097067>] EFLAGS: 00010246 CPU: 0 EIP is at bdevname+0x8/0x13 EAX: df4ddcf0 EBX: 00000000 ECX: df87fd54 EDX: 00000000 ESI: d5cfa0c0 EDI: 00000000 EBP: 00000001 ESP: df87fd38 DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 Process pdflush (pid: 151, ti=df87e000 task=df8caae0 task.ti=df87e000) Stack: c11582ff 0006d250 00000000 fffffffb 00000002 00000246 c1ae7e80 00011200 <0> 00011210 df83a9e0 c1043b26 df87fd60 00000004 00000101 c101be1c 00000000 <0> 00000000 d5cfa0c0 00000001 c11583e4 00000001 df83aa00 df83aa00 c107d6db Call Trace: [<c11582ff>] ? generic_make_request+0x1cc/0x209 [<c1043b26>] ? mempool_alloc+0x1e/0xd6 [<c101be1c>] ? __do_softirq+0x9b/0xc8 [<c11583e4>] ? submit_bio+0xa8/0xb0 [<c107d6db>] ? bio_alloc_bioset+0x3e/0xa4 [<c107ce92>] ? submit_bh+0x127/0x152 [<c107b117>] ? __block_write_full_page+0x1ff/0x2d8 [<c107eafd>] ? blkdev_get_block+0x0/0x46 [<c107cc5e>] ? block_write_full_page_endio+0xe2/0xec [<c1079ef7>] ? end_buffer_async_write+0x0/0xd4 [<c107eafd>] ? blkdev_get_block+0x0/0x46 [<c107cc72>] ? block_write_full_page+0xa/0xc [<c1079ef7>] ? end_buffer_async_write+0x0/0xd4 [<c104750c>] ? __writepage+0x8/0x1d [<c1047407>] ? write_cache_pages+0x1bf/0x2bc [<c1047504>] ? __writepage+0x0/0x1d [<c1047521>] ? generic_writepages+0x0/0x1f [<c104753d>] ? generic_writepages+0x1c/0x1f [<c1047562>] ? do_writepages+0x22/0x32 [<c1076444>] ? writeback_single_inode+0xad/0x1b2 [<c1076672>] ? generic_sync_sb_inodes+0x129/0x26e [<c1047c80>] ? pdflush+0x0/0x2d [<c1076820>] ? writeback_inodes+0x64/0xb4 [<c1047040>] ? background_writeout+0x5f/0x91 [<c1047bab>] ? __pdflush+0xcf/0x1a4 [<c1047ca9>] ? pdflush+0x29/0x2d [<c1046fe1>] ? background_writeout+0x0/0x91 [<c1047c80>] ? pdflush+0x0/0x2d [<c1026d72>] ? kthread+0x6b/0x70 [<c1026d07>] ? kthread+0x0/0x70 [<c1002f93>] ? kernel_thread_helper+0x7/0x10 Code: 09 56 53 68 f7 09 2e c1 eb 07 56 53 68 90 0a 2e c1 6a 20 55 e8 f0 01 0d 00 83 c4 14 5b 89 e8 5e 5f 5d c3 89 d1 8b 50 48 8b 40 54 <8b> 92 c0 00 00 00 e9 92 ff ff ff 53 89 d3 89 c2 81 e2 ff ff 0f EIP: [<c1097067>] bdevname+0x8/0x13 SS:ESP 0068:df87fd38 CR2: 00000000000000c0 -- Glenn Maynard -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
