On Wed, Aug 28, 2013 at 8:56 AM, Dan Mick <dan.m...@inktank.com> wrote: > Another developer just noticed this in testing; anyone have any ideas? >
btrfs_ioctl_start_sync() calls btrfs_attach_transaction_barrier() which further calls start_transaction() with "type == TRANS_ATTACH". In start_transaction(), sb_start_intwrite() is called when (type & __TRANS_FREEZABLE) is true. but (TRANS_ATTACH & __TRANS_FREEZABLE) is false. So we see the bad bad unlock balance bug. Yan, Zheng > On 08/22/2013 05:40 PM, Sage Weil wrote: >> >> I just noticed that there is a locking imbalance warning with sb_internal >> in the transaction commit code. I believe this has only started appearing >> recently (after I merged -rc5 into my testing tree), but I'm working on >> confirming that. The error is >> >> <4>[27034.835134] ===================================== >> <4>[27034.839854] [ BUG: bad unlock balance detected! ] >> <4>[27034.844576] 3.11.0-rc5-ceph-00061-g546140d #1 Not tainted >> <4>[27034.849992] ------------------------------------- >> <4>[27034.854713] ceph-osd/30797 is trying to release lock (sb_internal) >> at: >> <4>[27034.861304] [<ffffffffa0148fd8>] >> btrfs_commit_transaction_async+0x1c8/0x2c0 [btrfs] >> <4>[27034.868994] but there are no more locks to release! >> <4>[27034.873887] >> <4>[27034.873887] other info that might help us debug this: >> <4>[27034.880448] no locks held by ceph-osd/30797. >> <4>[27034.884733] >> <4>[27034.884733] stack backtrace: >> <4>[27034.889123] CPU: 0 PID: 30797 Comm: ceph-osd Not tainted >> 3.11.0-rc5-ceph-00061-g546140d #1 >> <4>[27034.897421] Hardware name: Dell Inc. PowerEdge R410/01V648, BIOS >> 1.6.3 02/07/2011 >> <4>[27034.904938] ffffffffa0148fd8 ffff88020baf9c68 ffffffff81642d85 >> 0000000000000007 >> <4>[27034.912411] ffff88021b32deb0 ffff88020baf9c98 ffffffff810ab89e >> ffff88020cff8000 >> <4>[27034.919883] 0000000000000246 ffff88020aaeddd0 ffffffffa0148fd8 >> ffff88020baf9ce8 >> <4>[27034.927358] Call Trace: >> <4>[27034.929836] [<ffffffffa0148fd8>] ? >> btrfs_commit_transaction_async+0x1c8/0x2c0 [btrfs] >> <4>[27034.937790] [<ffffffff81642d85>] dump_stack+0x46/0x58 >> <4>[27034.942951] [<ffffffff810ab89e>] >> print_unlock_imbalance_bug+0xfe/0x110 >> <4>[27034.949599] [<ffffffffa0148fd8>] ? >> btrfs_commit_transaction_async+0x1c8/0x2c0 [btrfs] >> <4>[27034.957552] [<ffffffff810aeafe>] lock_release+0x15e/0x220 >> <4>[27034.963069] [<ffffffffa0148fff>] >> btrfs_commit_transaction_async+0x1ef/0x2c0 [btrfs] >> <4>[27034.970850] [<ffffffff810af6f5>] ? >> trace_hardirqs_on_caller+0x105/0x1d0 >> <4>[27034.977587] [<ffffffffa0177907>] btrfs_ioctl_start_sync+0x47/0xc0 >> [btrfs] >> <4>[27034.984499] [<ffffffffa017c575>] btrfs_ioctl+0xe55/0x1af0 [btrfs] >> <4>[27034.990700] [<ffffffff8164ab2b>] ? _raw_spin_unlock+0x2b/0x40 >> <4>[27034.996552] [<ffffffff810b40b5>] ? do_futex+0xa45/0xbb0 >> <4>[27035.001885] [<ffffffff8119cf0c>] ? fget_light+0x3c/0x130 >> <4>[27035.007302] [<ffffffff811922a6>] do_vfs_ioctl+0x96/0x560 >> <4>[27035.012720] [<ffffffff8119cf6e>] ? fget_light+0x9e/0x130 >> <4>[27035.018137] [<ffffffff8119cf0c>] ? fget_light+0x3c/0x130 >> <4>[27035.023556] [<ffffffff81192801>] SyS_ioctl+0x91/0xb0 >> <4>[27035.028628] [<ffffffff813338fe>] ? >> trace_hardirqs_on_thunk+0x3a/0x3f >> <4>[27035.035089] [<ffffffff81653782>] system_call_fastpath+0x16/0x1b >> >> This is presumably some breakage in the freeze locking dance that goes on >> with async commits (btrfs_commit_transaction_async caller takes the freeze >> semaphore, do_async_commit releases it), but it's not obvious to me what >> broke yet. Unless this rings any bells for anyone, I'll go ahead and >> bisect. >> >> Thanks! >> sage >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in >> the body of a message to majord...@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
