Hi all, I think that my bloated kernel managed to create way too many entries in the dependency table. If that sounds right, I can send a patch to increase those. Attached /proc/lock_stat as requested as well. [ 1078.462898] BUG: MAX_LOCKDEP_ENTRIES too low! [ 1078.462898] turning off the locking correctness validator. [ 1078.463109] Please attach the output of /proc/lock_stat to the bug report [ 1078.463968] CPU: 1 PID: 26372 Comm: trinity-child16 Tainted: G W 3.13.0-rc 4-next-20131218-sasha-00014-gf6be483-dirty #4160 [ 1078.463968] ffff8801bb9b8c10 ffff8801bb34d788 ffffffff8439598c ffff8801bb34d788 [ 1078.464297] ffff8801bb9b8bd8 ffff8801bb34d798 ffffffff8118e681 ffff8801bb34d838 [ 1078.465304] ffffffff81193a7a ffff8801bb34d7b8 00000000810b4214 ffff8800cc1d83c0 [ 1078.466442] Call Trace: [ 1078.470111] [] dump_stack+0x52/0x7f [ 1078.470111] [] T.1062+0x31/0xb0 [ 1078.470111] [] check_prev_add+0x4ba/0x550 [ 1078.470111] [] ? kvm_clock_read+0x24/0x50 [ 1078.470121] [] ? kvm_clock_read+0x24/0x50 [ 1078.470121] [] validate_chain+0x6c3/0x7b0 [ 1078.470121] [] ? sched_clock_cpu+0x108/0x120 [ 1078.470121] [] __lock_acquire+0x4ad/0x580 [ 1078.470121] [] lock_acquire+0x182/0x1d0 [ 1078.470121] [] ? tcp_sendmsg+0x2c/0xd50 [ 1078.470121] [] lock_sock_nested+0x8a/0xa0 [ 1078.470121] [] ? tcp_sendmsg+0x2c/0xd50 [ 1078.470121] [] ? sched_clock+0x1d/0x30 [ 1078.470121] [] tcp_sendmsg+0x2c/0xd50 [ 1078.470121] [] ? sched_clock_cpu+0x108/0x120 [ 1078.470121] [] ? get_lock_stats+0x2a/0x60 [ 1078.470121] [] ? put_lock_stats+0xe/0x30 [ 1078.470121] [] ? inet_sendmsg+0x178/0x1f0 [ 1078.470121] [] ? delay_tsc+0xfa/0x120 [ 1078.470121] [] inet_sendmsg+0x1d3/0x1f0 [ 1078.470121] [] ? inet_recvmsg+0x200/0x200 [ 1078.470121] [] ? kvm_clock_read+0x24/0x50 [ 1078.470121] [] sock_sendmsg+0x90/0xc0 [ 1078.470121] [] ? kvm_clock_read+0x24/0x50 [ 1078.470121] [] ? kvm_clock_read+0x24/0x50 [ 1078.470121] [] ? sched_clock+0x1d/0x30 [ 1078.470121] [] ? sched_clock_local+0x25/0x90 [ 1078.470121] [] kernel_sendmsg+0x41/0x60 [ 1078.470121] [] sock_no_sendpage+0x96/0xb0 [ 1078.470121] [] ? inet_sendpage+0x198/0x240 [ 1078.470121] [] tcp_sendpage+0x34/0x80 [ 1078.470121] [] ? __const_udelay+0x29/0x30 [ 1078.470121] [] ? __rcu_read_unlock+0x44/0xb0 [ 1078.470121] [] inet_sendpage+0x1ff/0x240 [ 1078.470121] [] ? inet_release+0x1d0/0x1d0 [ 1078.470121] [] ? mark_held_locks+0x109/0x140 [ 1078.470121] [] kernel_sendpage+0x1b/0x30 [ 1078.470121] [] sock_sendpage+0x33/0x40 [ 1078.470121] [] pipe_to_sendpage+0x78/0x80 [ 1078.470121] [] splice_from_pipe_feed+0x8c/0x140 [ 1078.470121] [] ? direct_splice_actor+0x40/0x40 [ 1078.470121] [] ? pipe_lock+0x1d/0x20 [ 1078.470121] [] ? direct_splice_actor+0x40/0x40 [ 1078.470121] [] __splice_from_pipe+0x44/0x80 [ 1078.470121] [] ? direct_splice_actor+0x40/0x40 [ 1078.470121] [] ? direct_splice_actor+0x40/0x40 [ 1078.470121] [] splice_from_pipe+0x51/0x70 [ 1078.470121] [] ? rw_verify_area+0xcc/0x100 [ 1078.470121] [] generic_splice_sendpage+0x15/0x20 [ 1078.470121] [] do_splice+0x19c/0x310 [ 1078.470121] [] SyS_splice+0xb9/0x110 [ 1078.470121] [] tracesys+0xdd/0xe2 Thanks, Sasha