Messages in this thread | | | Date | Tue, 05 Feb 2013 18:26:25 -0800 | From | Ben Greear <> | Subject | Re: Question on lockdep and MAX_LOCK_DEPTH |
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On 02/05/2013 05:54 PM, Steven Rostedt wrote: > On Tue, Feb 05, 2013 at 05:10:37PM -0800, Ben Greear wrote: >> I'm debugging something that could be my own bug in my wanlink module (but then >> again, haven't seen this on 3.5 kernels, and my module is >> basically un-changed since then). >> >> I'm using lockdep, and keep seeing "BUG: MAX_LOCK_DEPTH too low". >> I tried changing the depth to 96 from 48, but it still hits. >> >> I also added debug_show_all_locks(); when this error >> case hits. I was assuming that if lockdep depth is large, >> there would be lots of locks held..but that does not >> seem to be the case??
> Perhaps what you want to do is add a: > > lockdep_print_held_locks(current);
Well, here it is..something is calling rcu_read_lock lots and lots, it seems. Any way to get a better idea of where those calls are made?
Showing all locks held in the system: 1 lock held by mingetty/2868: #0: (&tty->atomic_read_lock){+.+...}, at: [<ffffffff8132d503>] n_tty_read+0x28d/0x785 1 lock held by mingetty/2870: #0: (&tty->atomic_read_lock){+.+...}, at: [<ffffffff8132d503>] n_tty_read+0x28d/0x785 1 lock held by mingetty/2872: #0: (&tty->atomic_read_lock){+.+...}, at: [<ffffffff8132d503>] n_tty_read+0x28d/0x785 1 lock held by mingetty/2874: #0: (&tty->atomic_read_lock){+.+...}, at: [<ffffffff8132d503>] n_tty_read+0x28d/0x785 1 lock held by mingetty/2876: #0: (&tty->atomic_read_lock){+.+...}, at: [<ffffffff8132d503>] n_tty_read+0x28d/0x785 1 lock held by mingetty/2878: #0: (&tty->atomic_read_lock){+.+...}, at: [<ffffffff8132d503>] n_tty_read+0x28d/0x785 1 lock held by bash/3337: #0: (&tty->atomic_read_lock){+.+...}, at: [<ffffffff8132d503>] n_tty_read+0x28d/0x785 1 lock held by bash/3369: #0: (&tty->atomic_read_lock){+.+...}, at: [<ffffffff8132d503>] n_tty_read+0x28d/0x785
=============================================
96 locks held by swapper/0/0: #0: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #1: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #2: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #3: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #4: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #5: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #6: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #7: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #8: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #9: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #10: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #11: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #12: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #13: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #14: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #15: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #16: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #17: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #18: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #19: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #20: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #21: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #22: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #23: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #24: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #25: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #26: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #27: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #28: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #29: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #30: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #31: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #32: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #33: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #34: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #35: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #36: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #37: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #38: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #39: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #40: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #41: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #42: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #43: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #44: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #45: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #46: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #47: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #48: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #49: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #50: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #51: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #52: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #53: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #54: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #55: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #56: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #57: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #58: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #59: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #60: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #61: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #62: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #63: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #64: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #65: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #66: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #67: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #68: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #69: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #70: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #71: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #72: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #73: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #74: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #75: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #76: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #77: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #78: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #79: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #80: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #81: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #82: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #83: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #84: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #85: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #86: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #87: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #88: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #89: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #90: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #91: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #92: (rcu_read_lock){.+.+..}, at: [<ffffffff81476836>] rcu_read_lock+0x0/0x6f #93: (&(&wl->cfg_spin_lock)->rlock){..-...}, at: [<ffffffffa07bc4d0>] handle_rcv+0x15d/0x1dd [wanlink] #94: (&wl_threads[q].my_wq){..-...}, at: [<ffffffff810abe4d>] __wake_up+0x1d/0x48 #95: (&p->pi_lock){-.-.-.}, at: [<ffffffff810b09c1>] try_to_wake_up+0x29/0x20b BUG: MAX_LOCK_DEPTH too low, depth: 96 max: 96! turning off the locking correctness validator. Pid: 0, comm: swapper/0 Tainted: G C O 3.7.6+ #6 Call Trace: <IRQ> [<ffffffff810cda86>] __lock_acquire+0xe8d/0xf13 [<ffffffff810cc3e8>] ? mark_lock+0x2d/0x231 [<ffffffff810cdb70>] lock_acquire+0x64/0x81 [<ffffffff810b09c1>] ? try_to_wake_up+0x29/0x20b [<ffffffff81540435>] _raw_spin_lock_irqsave+0x4e/0x60 [<ffffffff810b09c1>] ? try_to_wake_up+0x29/0x20b [<ffffffff810b09c1>] try_to_wake_up+0x29/0x20b [<ffffffff810b0bb0>] default_wake_function+0xd/0xf [<ffffffff810ab34d>] __wake_up_common+0x49/0x7f [<ffffffff810abe64>] __wake_up+0x34/0x48 [<ffffffffa07bbe11>] handleRcvWlp+0xf4d/0xfd5 [wanlink] [<ffffffff810ccf7c>] ? __lock_acquire+0x383/0xf13 [<ffffffffa07bc325>] wp_handle_rcv_pkt+0x1f5/0x243 [wanlink] [<ffffffffa07bc51c>] handle_rcv+0x1a9/0x1dd [wanlink] [<ffffffff814777f5>] deliver_skb+0x58/0x60 [<ffffffff81477d04>] __netif_receive_skb+0x507/0x63c [<ffffffff810100b6>] ? read_tsc+0x9/0x1b [<ffffffff81479b3d>] netif_receive_skb+0x56/0x8b [<ffffffff8147a168>] ? __napi_gro_receive+0xf3/0x102 [<ffffffff81479c55>] napi_skb_finish+0x24/0x57 [<ffffffff8147a39d>] napi_gro_receive+0x91/0x96 [<ffffffffa0218d31>] e1000_receive_skb+0x50/0x5b [e1000e] [<ffffffffa021c00c>] e1000_clean_rx_irq+0x29f/0x341 [e1000e] [<ffffffffa021c5c6>] e1000e_poll+0x7d/0x239 [e1000e] [<ffffffff8147a523>] net_rx_action+0xb2/0x1e2 [<ffffffff8108ee06>] ? __do_softirq+0x6d/0x17b [<ffffffff8108ee44>] __do_softirq+0xab/0x17b [<ffffffff815473bc>] call_softirq+0x1c/0x30 [<ffffffff8100bd46>] do_softirq+0x46/0x9e [<ffffffff8108ec9f>] irq_exit+0x4e/0xcc [<ffffffff8100b635>] do_IRQ+0x97/0xae [<ffffffff81540f72>] common_interrupt+0x72/0x72 <EOI> [<ffffffff81011082>] ? mwait_idle+0x77/0x9f [<ffffffff81011079>] ? mwait_idle+0x6e/0x9f [<ffffffff81011379>] cpu_idle+0x68/0xbc [<ffffffff81522b4c>] rest_init+0x130/0x137 [<ffffffff81522a1c>] ? csum_partial_copy_generic+0x16c/0x16c [<ffffffff81ac3c87>] start_kernel+0x37f/0x38c [<ffffffff81ac373d>] ? repair_env_string+0x58/0x58 [<ffffffff81ac32dd>] x86_64_start_reservations+0xb8/0xbd [<ffffffff81ac33e3>] x86_64_start_kernel+0x101/0x110 BUG: sleeping function called from invalid context at /home/greearb/git/linux-3.7.dev.y/kernel/mutex.c:269 in_atomic(): 0, irqs_disabled(): 0, pid: 2476, name: kwanlink/0 INFO: lockdep is turned off. Pid: 2476, comm: kwanlink/0 Tainted: G C O 3.7.6+ #6 Call Trace: [<ffffffff810ac9b0>] __might_sleep+0x1a2/0x1ab [<ffffffff8153e549>] mutex_lock_nested+0x20/0x3b [<ffffffffa07bd4ac>] do_task+0x6d/0x248 [wanlink] [<ffffffffa07bd7e0>] wl_thread_task+0x159/0x202 [wanlink] [<ffffffffa07bd687>] ? do_task+0x248/0x248 [wanlink] [<ffffffff810a350b>] kthread+0xc2/0xca [<ffffffff810a3449>] ? __init_kthread_worker+0x56/0x56 [<ffffffff8154607c>] ret_from_fork+0x7c/0xb0 [<ffffffff810a3449>] ? __init_kthread_worker+0x56/0x56 BUG: sleeping function called from invalid context at /home/greearb/git/linux-3.7.dev.y/kernel/mutex.c:269
-- Ben Greear <greearb@candelatech.com> Candela Technologies Inc http://www.candelatech.com
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