After my system got stuck with 3.7.0-rc2 as reported in http://marc.info/?l=linux-kernel&m=135142236520624 LOCKDEP seem to blame XFS, because it found 2 possible deadlocks. But after these locking issues where fixed, my system got stuck again with 3.7.0-rc6 as reported in http://marc.info/?l=linux-kernel&m=135344072325490 Dave Chinner thinks its an issue within md, that it gets stuck and that will then prevent any further xfs activity, and that I should report it to the raid mailing list. The issue seems to be that multiple processes (kswapd0, xfsaild/md4 and flush-9:4) get stuck in md_super_wait() like this: [<ffffffff816b1224>] schedule+0x24/0x60 [<ffffffff814f9dad>] md_super_wait+0x4d/0x80 [<ffffffff8105ca30>] ? __init_waitqueue_head+0x60/0x60 [<ffffffff81500753>] bitmap_unplug+0x173/0x180 [<ffffffff810b6acf>] ? write_cache_pages+0x12f/0x420 [<ffffffff810b6700>] ? set_page_dirty_lock+0x60/0x60 [<ffffffff814e8eb8>] raid1_unplug+0x98/0x110 [<ffffffff81278a6d>] blk_flush_plug_list+0xad/0x240 [<ffffffff81278c13>] blk_finish_plug+0x13/0x50 The full hung-tasks stack traces and the output from SysRq+W can be found at http://marc.info/?l=linux-kernel&m=135344072325490 or in the LKML thread 'Hang in XFS reclaim on 3.7.0-rc3'. I tried to understand how this could happen, but I don't see anything wrong. Only that md_super_wait() looks like an open coded version of __wait_event() and could be replaced by using it. http://marc.info/?l=linux-raid&m=135283030027665 looks like the same issue, but using ext4 instead of xfs. My setup wrt. md is two normal sata disks on a normal ahci controller (AMD SB850 southbridge). Both disks are divided into 4 partitions and each one assembled into a separate raid1. One (md5) is used for swap, the others hold xfs filesystems for /boot/ (md4), / (md6) and /home/ (md7). I will try to provide any information you ask, but I can't reproduce the hang on demand so gathering more information about that state is not so easy, but I will try. Thanks for looking into this, Torsten -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
